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   28705篇
  免费   2560篇
  国内免费   414篇
耳鼻咽喉   428篇
儿科学   1227篇
妇产科学   1273篇
基础医学   2264篇
口腔科学   204篇
临床医学   2902篇
内科学   6597篇
皮肤病学   440篇
神经病学   1424篇
特种医学   957篇
外国民族医学   3篇
外科学   1925篇
综合类   1659篇
现状与发展   2篇
预防医学   3662篇
眼科学   933篇
药学   2408篇
  12篇
中国医学   429篇
肿瘤学   2930篇
  2024年   63篇
  2023年   858篇
  2022年   1241篇
  2021年   1877篇
  2020年   1724篇
  2019年   1891篇
  2018年   1703篇
  2017年   1253篇
  2016年   1073篇
  2015年   1069篇
  2014年   2056篇
  2013年   2320篇
  2012年   1344篇
  2011年   1468篇
  2010年   1192篇
  2009年   1205篇
  2008年   1247篇
  2007年   1240篇
  2006年   902篇
  2005年   820篇
  2004年   651篇
  2003年   630篇
  2002年   460篇
  2001年   393篇
  2000年   318篇
  1999年   334篇
  1998年   282篇
  1997年   261篇
  1996年   196篇
  1995年   183篇
  1994年   160篇
  1993年   130篇
  1992年   148篇
  1991年   109篇
  1990年   118篇
  1989年   72篇
  1988年   87篇
  1987年   64篇
  1986年   63篇
  1985年   89篇
  1984年   60篇
  1983年   54篇
  1982年   52篇
  1981年   56篇
  1980年   33篇
  1979年   30篇
  1978年   22篇
  1977年   20篇
  1976年   15篇
  1973年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
871.
ContextApproximately 72% of patients with an ankle sprain report residual symptoms 6 to 18 months later. Although 44% of patients return to activity in less than 24 hours after experiencing a sprain, residual symptoms should be evaluated in the long term to determine if deficits exist. These residual symptoms may be due to the quality of ligament tissue and motion after injury.ObjectiveTo compare mechanical laxity of the talocrural joint and dorsiflexion range of motion (DFROM) over time (24 to 72 hours, 2 to 4 weeks, and 6 months) after an acute lateral ankle sprain (LAS).DesignCross-sectional study.SettingAthletic training research laboratory.Patients or Other ParticipantsA total of 108 volunteers were recruited. Fifty-five participants had an acute LAS and 53 participants were control individuals without a history of LAS.Main Outcome Measure(s)Mechanical laxity (talofibular interval and anterior talofibular ligament length) was measured in inversion (INV) and via the anterior drawer test. The weight-bearing lunge test was conducted and DFROM was measured. The data were analyzed using repeated-measures analysis of variance, independent-samples t tests, and 1-way analysis of variance.ResultsOf the 55 LASs, 21 (38%) were grade I, 27 (49%) were grade II, and 7 (13%) were grade III. Increases were noted in DFROM over time, between 24 and 72 hours, at 2 to 4 weeks, and at 6 months (P < .05). The DFROM was less in participants with grade III than grade I LASs (P = .004) at 24 to 72 hours; INV length was greater at 24 to 72 hours than at 2 to 4 weeks (P = .023) and at 6 months (P = .035) than at 24 to 72 hours. The anterior drawer length (P = .001) and INV talofibular interval (P = .004) were greater in the LAS group than in the control group at 6 months.ConclusionsDifferences in range of motion and laxity were evident among grades at various time points and may indicate different clinical responses after an LAS.  相似文献   
872.
BackgroundFamilial hypercholesterolemia (FH) is an autosomal dominant disorder mainly caused by mutations in the low-density lipoprotein (LDL) receptor or associated genes, resulting in elevated serum cholesterol levels and an increased risk of premature atherosclerotic cardiovascular disease (ASCVD).ObjectiveWe aimed to evaluate the prognostic impact of cascade screening for FH.MethodsWe retrospectively investigated the health records of 1050 patients with clinically diagnosed FH, including probands and their relatives who were cascade-screened, who were referred to our institute. We used Cox models that were adjusted for established ASCVD risk factors to assess the association between cascade screening and major adverse cardiac events (MACE). The median period of follow-up evaluating MACE was 12.3 years (interquartile ranges [IQR] = 9.1–17.5 years), and MACE included death associated with ASCVD, or acute coronary syndrome.ResultsDuring the observation period, 113 participants experienced MACE. The mean age of patients identified through cascade screening was 18-years younger than that of the probands (38.7 yr vs. 57.0 yr, P < 0.0001), with a lower proportion of ASCVD risk factors. Interestingly, patients identified through cascade screening under milder lipid-lowering therapies were at reduced risk for MACE (hazard ratio [HR] = 0.67; 95%CI = 0.44 to 0.90; P = 0.0044) when compared with the probands, even after adjusting for those known risk factors, including age, and prior ASCVD.ConclusionsThe identification of patients with FH via cascade screening appeared to result in better prognosis.  相似文献   
873.
In this editorial we comment on the article by Cahn-Hidalgo D published in a recent issue of the World Journal of Psychiatry 2020; 10(1); 1-11. We focus on the importance of utilizing psychometrically valid cognitive screening tools when assessing for cognitive decline in older adults in a psychiatric outpatient setting. We compared the use of Cognivue® to use of the montreal cognitive assessment (MoCA) as a cognitive screening tool. A total of 58 patients aged 55 and over participated in this comparison study. Patients completed cognitive screening on Cognivue®, a new Food and Drug Administration-cleared computer screening device, and the MoCA. The results of patient performance using these two instruments were analyzed. Sixteen (28%) patients screened negative for cognitive impairment on both assessments. Forty-two (72%) patients screened positive on one or both of the assessments. There was 43% agreement between Cognivue® and the MoCA in identifying patients with cognitive impairment, and individual subtests were weakly correlated. The MoCA was determined to be the preferred instrument due to its high sensitivity and specificity (100% and 87%, respectively) when screening for cognitive impairment. We propose that the use of Cognivue® cognitive screening tool be closely reviewed until more research proves that the test meets the standards for reliability and validity. It is important for clinicians to remember that screeners should not be used to diagnosis patients with neurocognitive disorders; instead, they should be used to determine whether further evaluation is warranted. Additionally, misdiagnosing of neurocognitive disorders can pose unnecessary psychological and emotional harm to patients and their families and also lead to incorrect treatment and undue healthcare costs.  相似文献   
874.
目的分析兰州地区孕中期唐氏综合征(Down syndrome,Ds)筛查人群中位数分布并探讨其临床应用价值。方法采用时间分辨荧光分析法检测7172例妊娠14—20“周妊娠女性血清甲胎蛋白(alpha fetoprotein,AFP)和游离绒毛促性腺激素(free—beta human chorionic gonadotropin,Freeβ—HCG)的浓度。利用DS筛查风险评估软件(LifeCycle3.0,LC3.0)的MediansTool统计不同孕用AFP和Freeβ-HCG的人群中位数、体质量,对LC3.0的中位数方程、体质量校正方程系数进行修正。结果各孕周血清AFP中位数平均水平均比软件内嵌值低,而Freeβ-HCG中位数水平在孕17周前中位数高于软件内嵌值而孕17周后中位数则低于软件内嵌值。各体重血清AFP与软件内嵌值几乎吻合,而Freeβ-HCG中位数平均水平比软件内嵌值低。结论不同地区血清中位数的筛查切割值制定标准可能存在差异,有必要进一步建立本地区孕中期产前筛查人群中位数系统。  相似文献   
875.
Post-traumatic stress disorder (PTSD) is a distressing consequence of a traumatic event associated with an increased suicide risk and reduced quality of life. Surgeons often have low confidence in identifying psychological problems. The prevalence of PTSD following facial trauma ranges from 23% to 41%. This highlights the importance of identifying and managing at-risk patients to optimize both mental and physical recovery. IMPARTS (Integrating Mental and Physical healthcare: Research, Training and Services) provides electronic screening tools to guide the non-mental health clinician in the ‘real-time’ identification, documentation, and management of potential mental health problems. The bespoke IMPARTS facial trauma screening tool was piloted in a UK oral and maxillofacial surgery trauma clinic from July 2015 to November 2017. A total of 199 patients completed screening, with 48 (24%) screening positive for possible PTSD. Further analysis of these 48 patients revealed that four (8%) had PTSD symptoms alone; three (6%) also screened positive for depression, 17 (35%) for co-existing symptoms of anxiety, and 24 (50%) for PTSD, anxiety, and depression. IMPARTS was found to be a highly effective tool aiding the non-mental health clinician to screen for PTSD and initiate prompt management. The data captured informs planning of the psychological support service.  相似文献   
876.
This study examines trends and geographical differences in total and live birth prevalence of trisomies 21, 18 and 13 with regard to increasing maternal age and prenatal diagnosis in Europe. Twenty-one population-based EUROCAT registries covering 6.1 million births between 1990 and 2009 participated. Trisomy cases included live births, fetal deaths from 20 weeks gestational age and terminations of pregnancy for fetal anomaly. We present correction to 20 weeks gestational age (ie, correcting early terminations for the probability of fetal survival to 20 weeks) to allow for artefactual screening-related differences in total prevalence. Poisson regression was used. The proportion of births in the population to mothers aged 35+ years in the participating registries increased from 13% in 1990 to 19% in 2009. Total prevalence per 10 000 births was 22.0 (95% CI 21.7–22.4) for trisomy 21, 5.0 (95% CI 4.8–5.1) for trisomy 18 and 2.0 (95% CI 1.9–2.2) for trisomy 13; live birth prevalence was 11.2 (95% CI 10.9–11.5) for trisomy 21, 1.04 (95% CI 0.96–1.12) for trisomy 18 and 0.48 (95% CI 0.43–0.54) for trisomy 13. There was an increase in total and total corrected prevalence of all three trisomies over time, mainly explained by increasing maternal age. Live birth prevalence remained stable over time. For trisomy 21, there was a three-fold variation in live birth prevalence between countries. The rise in maternal age has led to an increase in the number of trisomy-affected pregnancies in Europe. Live birth prevalence has remained stable overall. Differences in prenatal screening and termination between countries lead to wide variation in live birth prevalence.  相似文献   
877.
Using whole‐genome array testing instead of karyotyping in prenatal diagnosis for all indications may be desirable because of the higher diagnostic yield and shorter reporting time. The goal of this research was finding the optimal array resolution that could replace routine prenatal karyotyping in cases without ultrasound abnormalities, for example, referred for advanced maternal age or abnormal first trimester screening. As variants of unknown clinical significance (VOUS), if reported, might complicate decision‐making about continuation of pregnancy, such an optimal array resolution should have a high abnormality detection rate and reveal a minimal amount of VOUS. The array data of 465 fetuses were retrospectively evaluated with several resolution levels, and the Decipher microdeletion/microduplication syndrome list was reviewed to assess what could be theoretically missed with a lower resolution. A 0.5‐Mb resolution showed a high diagnostic yield potential and significantly minimized the number of VOUS. Based on our experience, we recommend genomic SNP array as a first‐tier test in prenatal diagnosis. The resolution should be chosen based on the indication. In cases of fetal ultrasound abnormalities or intrauterine fetal death (IUFD), high‐resolution analysis should be done. In other cases, we advise replacing karyotyping by SNP array analysis with 0.5 Mb resolution.  相似文献   
878.
879.
BackgroundThe Y-Balance Test (YBT) assesses dynamic stability and neuromuscular control of the lower extremity. Several authors have analyzed kinematic predictors of YBT performance with conflicting results, but the influence of kinetic factors is not well understood.PurposeTo examine kinematic predictors of YBT performance and determine the joint kinetics which predict YBT performance.Study DesignCross-sectional study.MethodsThirty-one physically active individuals performed YBT trials on a force plate while whole body kinematics were recorded using a motion capture system. Sagittal, frontal, and transverse plane joint kinematics and joint moments were calculated at maximum reach in each YBT reach direction. Variables correlated with reach distances at the p < 0.2 level were entered into a stepwise linear regression.ResultsIn the anterior direction, knee flexion and torso rotation (R2=0.458, p<0.001) and knee extensor and hip abductor moments (R2=0.461, p<0.001) were the best kinematic and kinetic predictors of reach distance. In the posterior medial direction, hip flexion, ankle dorsiflexion, and ankle rotation accounted for 45.8% of the variance in reach direction (p<0.001) while hip and knee extensor, and hip abductor moments explained 72.6% of the variance in reach distance (p<0.001). In the posterior lateral direction, hip flexion and pelvic rotation (R2=0.696, p<.001) and hip extensor moments (R2=0.433, p=0.001) were the best kinematic and kinetic predictors of reach distance.ConclusionThe ability to generate large hip and knee joint moments in the sagittal and frontal plane are critical for YBT performance.Level of Evidence3.  相似文献   
880.
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