首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9216篇
  免费   691篇
  国内免费   541篇
耳鼻咽喉   12篇
儿科学   51篇
妇产科学   12篇
基础医学   619篇
口腔科学   94篇
临床医学   844篇
内科学   150篇
皮肤病学   6篇
神经病学   450篇
特种医学   586篇
外科学   4172篇
综合类   1473篇
预防医学   221篇
眼科学   260篇
药学   516篇
  7篇
中国医学   863篇
肿瘤学   112篇
  2024年   34篇
  2023年   207篇
  2022年   273篇
  2021年   377篇
  2020年   360篇
  2019年   264篇
  2018年   279篇
  2017年   315篇
  2016年   344篇
  2015年   357篇
  2014年   812篇
  2013年   711篇
  2012年   720篇
  2011年   682篇
  2010年   654篇
  2009年   519篇
  2008年   413篇
  2007年   409篇
  2006年   408篇
  2005年   297篇
  2004年   294篇
  2003年   296篇
  2002年   214篇
  2001年   172篇
  2000年   120篇
  1999年   152篇
  1998年   88篇
  1997年   87篇
  1996年   83篇
  1995年   78篇
  1994年   64篇
  1993年   59篇
  1992年   43篇
  1991年   26篇
  1990年   16篇
  1989年   24篇
  1988年   19篇
  1987年   20篇
  1986年   29篇
  1985年   28篇
  1984年   15篇
  1983年   11篇
  1982年   16篇
  1981年   10篇
  1980年   10篇
  1979年   12篇
  1978年   6篇
  1977年   6篇
  1976年   5篇
  1971年   3篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
81.
目的:研究刺腰夹脊联合推拿(四指推脊柱调整手法)对腰椎间盘突出症(LDH)患者腰椎功能及疼痛程度的影响。方法:将100例LDH患者纳入研究。将其遵循随机信封法等分成联合组及对照组。对照组实施腰椎牵引联合常规推拿治疗,联合组则实施针刺腰夹脊联合推拿(四指推脊柱调整手法)治疗。评价两组疗效,治疗前后疼痛程度,治疗前后腰椎功能,治疗前后血清炎症因子水平。结果:联合组治疗总有效率优于对照组(P<0.05)。治疗后联合组及对照组的PRI评分均低于治疗前,且联合组低于对照组(均P<0.05)。治疗后联合组腰椎最大活动度及肌力正常百分比均高于对照组(均P<0.05)。治疗后联合组血清白细胞介素-1(IL-1)、白细胞介素-6(IL-6)及肿瘤坏死因子-α(TNF-α)水平均低于对照组(均P<0.05)。结论:针刺腰夹脊联合推拿(四指推脊柱调整手法)可显著改善LDH患者腰椎功能,同时可减轻患者疼痛,缓解炎症反应,值得临床应用。  相似文献   
82.
目的:观察脊柱定点旋转复位手法治疗对腰椎间盘突出症(LDH)患者腰椎活动度及活动度对称性的疗效。方法:选择被诊断为LDH的住院患者613例,给予脊柱定点旋转复位法为主的手法治疗,2次/周,共3周,分别在治疗前及1个疗程后观察LDH患者疼痛VAS评分,腰椎屈曲、背伸、左右侧旋、左右侧屈活动度以及左右侧屈和左右侧旋两侧对称性的变化。结果:手法治疗后,LDH患者的VAS评分显著下降(P<0.01),腰椎6个方向的活动度均显著改善(P<0.01),两侧侧屈和侧旋运动的关节活动度的对称性显著增加(P<0.01)。结论:腰椎的关节活动度以及两侧运动的对称性可作为评价脊柱手法疗效评价的客观量化指标。脊柱定点旋转复位法改善了腰椎关节的灵活性以及运动时的左右对称性,可促进脊柱力学平衡的恢复。  相似文献   
83.
Background contextSurgical adverse event (AE) monitoring is imprecise, of uncertain validity, and tends toward underreporting. Reports focus on specific procedures rather than outcomes in the context of presenting diagnosis. Specific intraoperative (intraop) or postoperative (postop) AEs that may be independently associated with degenerative spondylolisthesis (DS) have never been reported.PurposeThe primary purpose was to assess the AE profile of surgically treated patients with L4–L5 DS. The secondary goal was to identify potential risk factors that correlate with those AEs.Study design/settingProspective cohort and academic quaternary spine center.Patient sampleNinety-two patients with L4–L5 DS were treated surgically, discharged from Vancouver General Hospital between January 1, 2009 and December 31, 2010.Outcome measuresIncidence rates and odds ratios.MethodsProspective AE data were analyzed using univariate analyses, forward selection regression models, and Spearman correlation coefficients. Results were compared with outcomes reported in the Spine Patient Outcomes Research Trial.ResultsNo AEs were seen in 57.6% of patients, one AE in 17.4%, and two or more AEs in 17.4%. Dural tears (6.5%) and intraop bone-implant interface failure requiring revision (3.3%) were the most common intraop AEs. Postoperatively, the most frequent AEs were urinary tract infection (10.9%), delirium (5.4%), neuropathic pain (4.4%), deep wound infection (3.3%), and superficial wound infection (3.3%). The odds of an intraop AE increased by 9% (95% confidence interval [CI] 1–18) per year of age at admission. Adjusted Charlson comorbidity index (CCI) did not correlate with number of AEs experienced. The odds of postop delirium correlated with CCI (odds ratio [OR] 3.39, 95% CI 1.12–10.24) and dural tear (OR 35.84, 95% CI 1.72–747.45). Length of stay was statistically significant and was influenced by two or more AEs, CCI, postop loss of correction, cerebrospinal fluid leak, deep wound infection, noninfected wound drainage, and gender.ConclusionsRisk of intraop AEs, but not postop AEs, increased with increasing age. Having multiple comorbidities does not predispose to more AEs. Infections predominate among the postop AEs. Patients at increased risk of delirium or of having an increased length of hospital stay may more easily be predicted. Studies specifically designed to prospectively assess AEs have the potential to more accurately identify postop AE rates.  相似文献   
84.
Background contextProspective registries have emerged as a feasible way to capture real-world care across large patient populations. However, the proven validity of more robust and cumbersome patient-reported outcomes instruments (PROis) must be balanced with what is feasible to apply in large-scale registry efforts.PurposeTo determine the relative validity and responsiveness of common PROis in accurately determining effectiveness of lumbar fusion for degenerative lumbar spondylolisthesis in registry efforts.Study designProspective cohort study.Patient sampleFifty-eight patients undergoing transforaminal lumbar interbody fusion (TLIF) for degenerative lumbar spondylolisthesisOutcome measuresPatient-reported outcome measures for pain (numeric rating scale for back and leg pain [NRS-BP, NRS-LP]), disability (Oswestry Disability Index [ODI]), general health (Short Form [SF]-12), quality of life (QOL) (EuroQol five dimensions [EQ-5D]), and depression (Zung depression scale [ZDS]) were assessed.MethodsFifty-eight patients undergoing primary TLIF for lumbar spondylolisthesis were entered into an institutional registry and prospectively followed for 2 years. Baseline and 2-year patient-reported outcomes were assessed. To assess the validity of PROis to discriminate between effective and noneffective improvements, receiver operating characteristic curves were generated for each outcomes instrument. An area under the curve (AUC) of ≥0.80 was considered an accurate discriminator. The difference between standardized response means (SRMs) in patients reporting meaningful improvement versus not was calculated to determine the relative responsiveness of each instrument.ResultsFor pain and disability, ODI had AUC=0.94, suggesting it as an accurate discriminator of meaningful improvement. Oswestry Disability Index was most responsive to postoperative improvement (SRM difference: 2.18), followed by NRS-BP and NRS-LP. For general health and QOL, SF-12 physical component score (AUC: 0.90), ZDS (AUC: 0.89), and SF-12 mental component score (AUC: 0.85) were all accurate discriminators of meaningful improvement, however, EQ-5D was most accurate (AUC: 0.97). EuroQol five dimensions was also most responsive (SRM difference: 2.83).ConclusionsFor pain and disability, ODI was the most valid and responsive measure of effectiveness of lumbar fusion. Numeric rating scale-BP and NRS-LP should not be used as substitutes for ODI in measuring effectiveness of care in registry efforts. For health-related QOL, EQ-5D was the most valid and responsive measure of improvement, however, SF-12 and ZDS are valid alternatives with less responsiveness.  相似文献   
85.
86.

Background context

Magnetic resonance imaging (MRI) is frequently used in the evaluation of degenerative conditions in the lumbar spine. The relative interrater and intrarater agreements of MRI findings across different pathologic conditions are underexplored, as most studies are focused on specific findings.

Purpose

The purpose of this study was to characterize the interrater and intrarater agreements of MRI findings used to assess the degenerative lumbar spine.

Study design

A retrospective diagnostic study at a large academic medical center was undertaken with a panel of orthopedic surgeons and musculoskeletal radiologists to assess lumbar MRIs using standardized criteria.

Patient sample

Seventy-five subjects who underwent routine lumbar spine MRI at our institution were included.

Outcome measures

Each MRI study was assessed for 10 lumbar degenerative findings using standardized criteria. Lumbar vertebral levels were assessed independently, where applicable, for a total of 52 data points collected per study.

Methods

T2-weighted axial and sagittal MRI sequences were presented in random order to the four reviewers (two orthopedic spine surgeons and two musculoskeletal radiologists) independently to determine interrater agreement. The first 10 studies were reevaluated at the end to determine intrarater agreement. Images were assessed using standardized and pilot-tested criteria to assess disc degeneration, stenosis, and other degenerative changes. Interrater and intrarater absolute percent agreements were calculated. To highlight the most clinically important MRI disagreements, a modified agreement analysis was also performed (in which disagreements between the lowest two severity grades for applicable conditions were ignored). Fleiss kappa coefficients for interrater agreement were determined.

Results

The overall absolute and modified interrater agreements were 76.9% and 93.5%, respectively. The absolute and modified intrarater agreements were 81.3% and 92.7%, respectively. Average Fleiss kappa coefficient was 0.431, suggesting moderate overall agreement. However, when stratified by condition, absolute interrater agreement ranged from 65.1% to 92.0%. Disc hydration, disc space height, and bone marrow changes exhibited the lowest absolute interrater agreements. The absolute intrarater agreement had a narrower range, from 74.5% to 91.5%. Fleiss kappa coefficients ranged from fair-to-substantial agreement (0.282–0.618).

Conclusions

Even in a study using standardized evaluation criteria, there was significant variability in the interrater and intrarater agreements of MRI in assessing different degenerative conditions of the lumbar spine. Clinicians should be aware of the condition-specific diagnostic limitations of MRI interpretation.  相似文献   
87.
Background contextAlthough multiple mechanisms of device attachment to the spinous processes exist, there is a paucity of data regarding lumbar spinous process morphology and peak failure loads.PurposeUsing an in vitro human cadaveric spine model, the primary objective of the present study was to compare the peak load and mechanisms of lumbar spinous process failure with variation in spinous process hole location and pullout direction. A secondary objective was to provide an in-depth characterization of spinous process morphology.Study designBiomechanical and anatomical considerations in lumbar spinous process fixation using an in vitro human cadaveric model.MethodsA total of 12 intact lumbar spines were used in the current investigation. The vertebral segments (L1–L5) were randomly assigned to one of five treatment groups with variation in spinous process hole placement and pullout direction: (1) central hole placement with superior pullout (n=10), (2) central hole placement with inferior pullout (n=10), (3) inferior hole placement with inferior pullout (n=10), (4) superior hole placement with superior pullout (n=10), and (5) intact spinous process with superior pullout (n=14). A 4-mm diameter pin was placed through the hole followed by pullout testing using a material testing system. As well, the bone mineral density (BMD) (g/cm3) was measured for each segment. Data were quantified in terms of anatomical dimensions (mm), peak failure loads (newtons [N]), and fracture mechanisms, with linear regression analysis to identify relationships between anatomical and biomechanical data.ResultsBased on anatomical comparisons, there were significant differences between the anteroposterior and cephalocaudal dimensions of the L5 spinous process versus L1–L4 (p<.05). Statistical analysis of peak load at failure of the four reconstruction treatments and intact condition demonstrated no significant differences between treatments (range, 350–500 N) (p>.05). However, a significant linear correlation was observed between peak failure load and anteroposterior and cephalocaudal dimensions (p<.05). Correlation between BMD and peak spinous processes failure load was approaching statistical significance (p=.08). 30 of 54 specimens failed via direct pullout (plow through), whereas 8 of 54 specimens demonstrated spinous process fracture. The remaining cases failed via plow through followed by fracture of the spinous process (16 of 54; 29%).ConclusionsThe present study demonstrated that variation in spinous process hole placement did not significantly influence failure load. However, there was a strong linear correlation between peak failure load and the anteroposterior and cephalocaudal anatomical dimensions. From a clinical standpoint, the findings of the present study indicate that attachment through the spinous process provides a viable alternative to attachment around the spinous processes. In addition, the anatomical dimensions of the lumbar spinous processes have a greater influence on biomechanical fixation than either hole location or BMD.  相似文献   
88.
Background contextThere is a persistent trend for more outpatient lumbar discectomies in the United States.PurposeTo investigate the characteristics of the patients selected for ambulatory procedures.Study designRetrospective cohort study.Patient sampleForty-seven thousand one hundred twenty-five patients who underwent outpatient and 102,592 patients undergoing inpatient lumbar discectomies and were were registered in the State Ambulatory Surgery Database (SASD) and State Inpatient Database (SID), respectively, for New York, California, Florida, and North Carolina from 2005 to 2008.Outcome measuresRate of outpatient procedures, 30-day readmissions, and hospital charges.MethodsWe performed a retrospective cohort study involving patients who underwent outpatient and inpatient lumbar discectomies and were registered in SASD and SID, respectively, for New York, California, Florida, and North Carolina from 2005 to 2008. Logistic regression models were used to demonstrate the association of socioeconomic factors with the odds of undergoing an outpatient procedure.ResultsMale gender (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.03–1.08), private insurance (OR, 1.93; 95% CI, 1.86–2.01), lower Charlson Comorbidity Index (OR, 4.04; 95% CI, 3.17–5.16), and higher volume hospitals (OR, 1.06; 95% CI, 1.04–1.08) were significantly associated with outpatient procedures. Higher income (OR, 0.83; 95% CI, 0.81–0.85), older age (OR, 0.996; 95% CI, 0.995–0.997), coverage by Medicaid (OR, 0.89; 95% CI, 0.83–0.96), African Americans (OR, 0.65; 95% CI, 0.60–0.70), and other minority races were associated with decreased odds of outpatient procedures. The rate of 30-day postoperative readmissions was higher among inpatients. Institutional charges were significantly lower for outpatient lumbar discectomies. The median charge for inpatient surgery was $24,273 as compared with $11,339 for the outpatient setting (p<.0001).ConclusionsAccess to ambulatory lumbar discectomies appears to be more common for younger, white, male patients, with private insurance and less comorbidities, in the setting of higher volume hospitals. Further investigation is needed in the direction of mapping these disparities for appropriate resource utilization.  相似文献   
89.
Background contextPrior studies on the impact of obesity on spine surgery outcomes have focused mostly on lumbar fusions, do not examine lumbar discectomies or decompressions, and have shown mixed results regarding complications. Differences in sample sizes and body mass index (BMI) thresholds for the definition of the obese versus comparison cohorts could account for the inconsistencies in the literature.PurposeThe purpose of the study was to analyze whether different degrees of obesity influence the complication rates in patients undergoing lumbar spine surgery.Study design/settingThis was a retrospective cohort analysis of prospectively collected data using the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database from 2005 to 2010.Patient samplePatients in the de-identified, risk-adjusted, and multi-institutional ACS NSQIP database undergoing lumbar anterior fusion, posterior fusion, transforaminal lumbar interbody fusion/posterior lumbar interbody fusion (TLIF/PLIF), discectomy, or decompression were included.Outcome measuresPrimary outcome measures were 30-day postsurgical complications, including pulmonary embolism and deep vein thrombosis, death, system-specific complications (wound, pulmonary, urinary, central nervous system, and cardiac), septic complications, and having one or more complications overall. Secondary outcomes were time spent in the operating room, blood transfusions, length of stay, and reoperation within 30 days.MethodsPatients undergoing lumbar anterior fusion, posterior fusion, TLIF/PLIF, discectomy, or decompression in the ACS NSQIP, 2005 to 2010, were categorized into four BMI groups: nonobese (18.5–29.9 kg/m2), Obese I (30–34.9 kg/m2), Obese II (35–39.9 kg/m2), and Obese III (greater than or equal to 40 kg/m2). Obese I to III patients were compared with patients in the nonobese category using chi-square test and analysis of variance. Multivariate linear/logistic regression models were used to adjust for preoperative risk factors.ResultsData were available for 10,387 patients undergoing lumbar surgery. Of these, 4.5% underwent anterior fusion, 17.9% posterior fusion, 6.3% TLIF/PLIF, 40.7% discectomy, and 30.5% decompression. Among all patients, 25.6% were in the Obese I group, 11.5% Obese II, and 6.9% Obese III. On multivariate analysis, Obese I and III had a significantly increased risk of urinary complications, and Obese II and III patients had a significantly increased risk of wound complications. Only Obese III patients, however, had a statistically increased risk of having increased time spent in the operating room, an extended length of stay, pulmonary complications, and having one or more complications (all p<.05).ConclusionsPatients with high BMI appear to have higher complication rates after lumbar surgery than patients who are nonobese. However, the complication rates seem to increase substantially for Obese III patients. These patients have longer times spent in the operating room, extended hospitals stays, and an increased risk for wound, urinary, and pulmonary complications and for having at least one or more complications overall. Surgeons should be aware of the increased risk of multiple complications for patients with BMI greater than or equal to 40 kg/m2.  相似文献   
90.
Background contextLumbar interbody fusion (LIF) techniques have been used for years to treat a number of pathologies of the lower back. These procedures may use an anterior, posterior, or combined surgical approach. Each approach is associated with a unique set of complications, but the exact prevalence of complications associated with each approach remains unclear.PurposeTo investigate the rates of perioperative complications of anterior lumbar interbody fusion (ALIF), posterior/transforaminal lumbar interbody fusion (P/TLIF), and LIF with a combined anterior-posterior interbody fusion (APF).Study design/settingRetrospective review of national data from a large administrative database.Patient samplePatients undergoing ALIF, P/TLIF, or APF.Outcome measuresPerioperative complications, length of stay (LOS), total costs, and mortality.MethodsThe Nationwide Inpatient Sample database was queried for patients undergoing ALIF, P/TLIF, or APF between 2001 and 2010 as identified via International Classification of Diseases, ninth revision codes. Univariate analyses were carried out comparing the three cohorts in terms of the outcomes of interest. Multivariate analysis for primary outcomes was carried out adjusting for overall comorbidity burden, race, gender, age, and length of fusion. National estimates of annual total number of procedures were calculated based on the provided discharge weights. Geographic distribution of the three cohorts was also investigated.ResultsAn estimated total of 923,038 LIFs were performed between 2001 and 2010 in the United States. Posterior/transforaminal lumbar interbody fusions accounted for 79% to 86% of total LIFs between 2001 and 2010, ALIFs for 10% to 15%, and APF decreased from 10% in 2002 to less than 1% in 2010. On average, P/TLIF patients were oldest (54.55 years), followed by combined approach (47.23 years) and ALIF (46.94 years) patients (p<.0001). Anterior lumbar interbody fusion, P/TLIF, and combined surgical costs were $75,872, $65,894, and $92,249, respectively (p<.0001). Patients in the P/TLIF cohort had the greatest number of comorbidities, having the highest prevalence for 10 of 17 comorbidities investigated. Anterior-posterior interbody fusion group was associated with the greatest number of complications, having the highest incidence of 12 of the 16 complications investigated.ConclusionsThese data help to define the perioperative risks for several LIF approaches. Comparison of outcomes showed that a combined approach is more expensive and associated with greater LOS, whereas ALIF is associated with the highest postoperative mortality. These trends should be taken into consideration during surgical planning to improve clinical outcomes.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号