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   332624篇
  免费   27647篇
  国内免费   7651篇
耳鼻咽喉   4115篇
儿科学   7208篇
妇产科学   5346篇
基础医学   28878篇
口腔科学   8773篇
临床医学   35222篇
内科学   37960篇
皮肤病学   3476篇
神经病学   17756篇
特种医学   10490篇
外国民族医学   20篇
外科学   31706篇
综合类   54581篇
现状与发展   19篇
一般理论   32篇
预防医学   38185篇
眼科学   4204篇
药学   31026篇
  495篇
中国医学   35163篇
肿瘤学   13267篇
  2023年   5813篇
  2022年   8652篇
  2021年   14409篇
  2020年   14543篇
  2019年   15652篇
  2018年   14180篇
  2017年   12674篇
  2016年   11787篇
  2015年   11054篇
  2014年   21886篇
  2013年   22740篇
  2012年   19423篇
  2011年   21314篇
  2010年   17561篇
  2009年   15085篇
  2008年   14317篇
  2007年   14818篇
  2006年   12908篇
  2005年   11220篇
  2004年   9431篇
  2003年   8401篇
  2002年   6701篇
  2001年   5884篇
  2000年   4980篇
  1999年   4187篇
  1998年   3348篇
  1997年   3242篇
  1996年   2650篇
  1995年   2818篇
  1994年   2600篇
  1993年   2164篇
  1992年   2020篇
  1991年   1812篇
  1990年   1542篇
  1989年   1508篇
  1988年   1406篇
  1987年   1252篇
  1986年   1166篇
  1985年   2779篇
  1984年   2946篇
  1983年   1900篇
  1982年   2486篇
  1981年   1828篇
  1980年   1618篇
  1979年   1423篇
  1978年   1165篇
  1977年   931篇
  1976年   991篇
  1975年   644篇
  1974年   536篇
排序方式: 共有10000条查询结果,搜索用时 28 毫秒
101.
In this paper, we argue that understanding and addressing the problem of poor-quality medical products requires a more interdisciplinary approach than has been evident to date. While prospective studies based on rigorous standardized methodologies are the gold standard for measuring the prevalence of poor-quality medical products and understanding their distribution nationally and internationally, they should be complemented by social science research to unpack the complex set of social, economic, and governance factors that underlie these patterns. In the following sections, we discuss specific examples of prospective quality surveys and of social science studies, highlighting the value of cross-sector partnerships in driving high-quality, policy-relevant research in this area.  相似文献   
102.
103.
摘 要 目的 探讨传统膀胱截石位与改良膀胱截石位对超声评估前盆腔相关参数的影响。方法 应用交叉设计二阶段法,将100例行盆底超声检查的患者随机分为两组(每组各50例),A组采用先传统体位后改良体位规范盆底超声,B组采用先改良体位后传统体位规范盆底超声检查,对比分析两种体位检查的成功率、静息状态、最大Valsalva动作时各盆腔参数的差异。结果 改良体位获得最大Valsalva动作的成功率大于传统体位(96% vs 90%),差异有统计学意义(χ2=4.348,P=0.037)。两种体位在静息状态时膀胱颈到参考线的距离、膀胱后角、尿道倾斜角比较差异均无统计学意义;改良体位在最大Valsalva动作时的膀胱后角、膀胱颈移动度、尿道旋转角均大于传统体位,差异均有统计学意义(P<0.05),且上述参数受实验顺序影响不明显,改良体位下尿道漏斗形成率大于传统体位,差异有统计学意义(P<0.05)。结论 体位因素对评估前盆腔相关参数具有影响,改良体位法获得的前盆腔相关参数与传统体位有一定差异,在临床应用中应注意合理解析。  相似文献   
104.
BackgroundThe growing enthusiasm for the use of reverse shoulder arthroplasty (RSA) in the treatment of primary glenohumeral osteoarthritis (GHOA) with an intact rotator cuff is based on data derived from single-center studies with limited generalizability and follow-up. This study compared patient-reported outcomes (PROs) between RSA and total shoulder arthroplasty (TSA) for the treatment of primary GHOA with up to 5-year follow-up and examined temporal trends in the treatment of GHOA between 2012 and 2021.MethodsA retrospective review was performed on patients with primary GHOA undergoing primary arthroplasty surgery from the Surgical Outcomes System global registry between 2012 and 2021. PROs including the American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numeric Evaluation (SANE) score, and visual analog scale (VAS) for pain were compared between RSA and TSA at 1, 2, and 5 years postoperatively.ResultsA total of 4451 patients were included, with 2693 (60.5%) undergoing TSA and 1758 (39.5%) undergoing RSA. Both RSA and TSA provided clinically excellent outcomes at 1 year postoperatively (ASES: 80.8 ± 17.9 vs. 85.9 ± 15.2, respectively; SANE: 74.8 ± 24.7 vs. 79.5 ± 22.9; VAS pain: 1.3 ± 2.0 vs. 1.1 ± 1.7; all P < .05) that were maintained at 2 years (ASES: 81.3 ± 19.3 vs. 87.3 ± 14.9; SANE: 74.8 ± 26.2 vs. 79.7 ± 24.7; VAS pain: 1.3 ± 2.1 vs. 1.0 ± 1.6; all P < .05) and 5 years (ASES: 81.7 ± 16.5 vs. 86.9 ± 15.3; SANE: 71.6 ± 28.5 vs. 78.2 ± 25.9; VAS pain: 1.0 ± 1.7 vs. 1.0 ± 1.7; all P < .05), with statistical significance favoring TSA. After controlling for age and sex, there was an adjusted difference of 4.5 units in the ASES score favoring TSA (P = .005) at 5 years postoperatively but no differences in adjusted SANE (P = .745) and VAS pain (P = .332) scores. The use of RSA for GHOA grew considerably over time, from representing only 17% of all replacements performed for GHOA in 2012 to nearly half (47%) in 2021 (P < .001).ConclusionRSA as a treatment for GHOA with an intact rotator cuff seems to yield PROs that are largely clinically equivalent to TSA extending to 5 years postoperatively. The observed statistical significance favoring TSA appears to be of marginal clinical benefit based on established minimal clinically important differences and may be a result of the large sample size. Further research using more granular clinical data and examining differences in range of motion and complications is warranted as it may change the value analysis.  相似文献   
105.
106.
《Injury》2023,54(7):110761
ObjectivesHistorically, pelvic ring fractures (PRF) are considered to occur predominantly in the anterior ring and therfore to be mechanically stable. Combined anterior and posterior (A + P) PRF are expected to be less mechanically stable and therefore to be associated with higher levels of pain and reduced mobility compared to isolated anterior fractures. The current study investigates the clinical relevance of combined A + P PRF in elderly patients.MethodsA prospective multicentre cohort study was conducted in patients >70 years of age with anterior PRF after low-energy trauma diagnosed on conventional radiographs. All patients underwent an additional CT-scan. Patients were divided into two groups; isolated anterior or combined A + P fractures. Patients were treated conservatively with adequate analgesia for at least one week. If patients could not be mobilised after conservative treatment, surgical fixation was performed. Numerical Rating Scale (NRS) pain scores, dependence on walking aids and Activities of Daily Living scores (ADL) were measured at 2–4 weeks, and 3, 6 and 12 months after fracture.Results102 patients (age 81.1 ± 7.6 years) were included. Isolated anterior fractures were diagnosed in 25 (24.5%) and A + P fractures in 77 (75.5%) patients. Baseline characteristics did not differ between the two groups. Most patients were successfully treated conservatively and 5 (4.9%) underwent percutaneous trans-iliac, trans-sacral screw fixation after failure of conservative treatment. At 2–4 weeks post trauma, patients with A + P fractures had similar median pain scores (3 (range 0–8) vs. 5 (0–10), p = 0.19) and ADL scores (85 (25–100) vs. 78.6 (5–100), p = 0.67), but were more dependent on walking aids (92.8% vs. 72.2%; p = 0.02) compared to patients with isolated anterior fractures. There were no significant differences at 3 months. At one year follow-up the median NRS pain and ADL scores for both fracture groups were 0 and 100, respectively. Mortality was 10.8%, and additional loss to follow-up was 17.6%.ConclusionsThe vast majority of elderly patients with PRF have combined A + P fractures. The clinical implications of additional posterior pelvic ring fractures in elderly patients appears to be limited.  相似文献   
107.
108.
BackgroundParkinson’s disease (PD) is a chronic and progressive neurodegenerative disease with no cure, presenting a challenging diagnosis and management. However, despite a significant number of criteria and guidelines have been proposed to improve the diagnosis of PD and to determine the PD stage, the gold standard for diagnosis and symptoms monitoring of PD is still mainly based on clinical evaluation, which includes several subjective factors. The use of machine learning (ML) algorithms in spatial-temporal gait parameters is an interesting advance with easy interpretation and objective factors that may assist in PD diagnostic and follow up.Research questionThis article studies ML algorithms for: i) distinguish people with PD vs. matched-healthy individuals; and ii) to discriminate PD stages, based on selected spatial-temporal parameters, including variability and asymmetry.MethodsGait data acquired from 63 people with PD with different levels of PD motor symptoms severity, and 63 matched-control group individuals, during self-selected walking speed, was study in the experiments.ResultsIn the PD diagnosis, a classification accuracy of 84.6 %, with a precision of 0.923 and a recall of 0.800, was achieved by the Naïve Bayes algorithm. We found four significant gait features in PD diagnosis: step length, velocity and width, and step width variability. As to the PD stage identification, the Random Forest outperformed the other studied ML algorithms, by reaching an Area Under the ROC curve of 0.786. We found two relevant gait features in identifying the PD stage: stride width variability and step double support time variability.SignificanceThe results showed that the studied ML algorithms have potential both to PD diagnosis and stage identification by analysing gait parameters.  相似文献   
109.
目的:通过检索《针灸大成》中与气海穴治疗作用相关的文献条文,总结气海穴在治疗各系统疾病中运用频次较高的疾病及其配穴规律,为临床针灸对气海穴的使用提供理论支持。方法:以《中华医典》(第五版)中《针灸大成》作为文献检索来源,将气海穴及气海穴的别称“脖胦”“下肓”“丹田”“肓之原”“肓原”“下言”和“气泽”为检索词,用计算机检索工具及人工检索相结合的方法检索符合要求的文献条文,通过建立本研究的数据库,频次分析、条形统计图比较分析等方法,总结出气海穴在治疗各系统疾病中的运用频次及其配穴规律。结果:在《针灸大成》所涉及的条文中,气海穴尤善治疗内科疾病,在治疗内科疾病中排名前3位的是脾胃系病症、气血津液疾病、肾系病症和妇科疾病,气海穴配穴习惯为上下配穴法,同名经配穴法,以及前后配穴法,其中主要为前后配穴法和同名经配穴法。结论:气海穴《针灸大成》中单穴应用占比最高,而在气海穴众多配穴中,运用了本经配穴法、上下配穴法、前后配穴法,配穴归经主要来自任脉和足太阳膀胱经。同名经配穴法,同气相求,可增加疗效;与气海穴配伍较多的足太阳膀胱经以背腧穴为主,此为前后配穴法,亦称腹背阴阳配穴法,腹部为阴,腰背为阳,前后配穴法可起到“从阳引阴”亦可“从阴引阳”的作用,以达到调节阴阳,调和脏法,调畅经络的目的。  相似文献   
110.
BackgroundPretest probability (PTP) calculators utilize epidemiological-level findings to provide patient-level risk assessment of obstructive coronary artery disease (CAD). However, their limited accuracies question whether dissimilarities in risk factors necessarily result in differences in CAD. Using patient similarity network (PSN) analyses, we wished to assess the accuracy of risk factors and imaging markers to identify ≥50% luminal narrowing on coronary CT angiography (CCTA) in stable chest-pain patients.MethodsWe created four PSNs representing: patient characteristics, risk factors, non-coronary imaging markers and calcium score. We used spectral clustering to group individuals with similar risk profiles. We compared PSNs to a contemporary PTP score incorporating calcium score and risk factors to identify ≥50% luminal narrowing on CCTA in the CT-arm of the PROMISE trial. We also conducted subanalyses in different age and sex groups.ResultsIn 3556 individuals, the calcium score PSN significantly outperformed patient characteristic, risk factor, and non-coronary imaging marker PSNs (AUC: 0.81 vs. 0.57, 0.55, 0.54; respectively, p ?< ?0.001 for all). The calcium score PSN significantly outperformed the contemporary PTP score (AUC: 0.81 vs. 0.78, p ?< ?0.001), and using 0, 1–100 and ?> ?100 cut-offs provided comparable results (AUC: 0.81 vs. 0.81, p ?= ?0.06). Similar results were found in all subanalyses.ConclusionCalcium score on its own provides better individualized obstructive CAD prediction than contemporary PTP scores incorporating calcium score and risk factors. Risk factors may not be able to improve the diagnostic accuracy of calcium score to predict ≥50% luminal narrowing on CCTA.  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