全文获取类型
收费全文 | 5131篇 |
免费 | 681篇 |
国内免费 | 91篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 372篇 |
妇产科学 | 56篇 |
基础医学 | 405篇 |
口腔科学 | 284篇 |
临床医学 | 535篇 |
内科学 | 1035篇 |
皮肤病学 | 28篇 |
神经病学 | 1044篇 |
特种医学 | 151篇 |
外科学 | 562篇 |
综合类 | 151篇 |
预防医学 | 873篇 |
眼科学 | 52篇 |
药学 | 190篇 |
中国医学 | 14篇 |
肿瘤学 | 136篇 |
出版年
2024年 | 37篇 |
2023年 | 186篇 |
2022年 | 241篇 |
2021年 | 329篇 |
2020年 | 312篇 |
2019年 | 351篇 |
2018年 | 349篇 |
2017年 | 273篇 |
2016年 | 229篇 |
2015年 | 230篇 |
2014年 | 326篇 |
2013年 | 429篇 |
2012年 | 210篇 |
2011年 | 221篇 |
2010年 | 191篇 |
2009年 | 213篇 |
2008年 | 207篇 |
2007年 | 181篇 |
2006年 | 168篇 |
2005年 | 125篇 |
2004年 | 122篇 |
2003年 | 122篇 |
2002年 | 106篇 |
2001年 | 55篇 |
2000年 | 55篇 |
1999年 | 60篇 |
1998年 | 49篇 |
1997年 | 66篇 |
1996年 | 36篇 |
1995年 | 44篇 |
1994年 | 35篇 |
1993年 | 34篇 |
1992年 | 38篇 |
1991年 | 42篇 |
1990年 | 33篇 |
1989年 | 30篇 |
1988年 | 29篇 |
1987年 | 28篇 |
1986年 | 18篇 |
1985年 | 19篇 |
1984年 | 19篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有5903条查询结果,搜索用时 15 毫秒
91.
92.
93.
Women with polycystic ovary syndrome demonstrate worsening markers of cardiovascular risk over the short‐term despite declining hyperandrogenaemia: Results of a longitudinal study with community controls 下载免费PDF全文
94.
Abigail B. Shoben Kyle D. Rudser Scott S. Emerson 《Journal of biopharmaceutical statistics》2017,27(1):135-147
Statistical intuition suggests that increasing the total number of observations available for analysis should increase the precision with which parameters can be estimated. Such monotonic growth of statistical information is of particular importance when data are analyzed sequentially, such as in confirmatory clinical trials. However, monotonic information growth is not always guaranteed, even when using a valid, but inefficient estimator. In this article, we demonstrate the theoretical possibility of nonmonotonic information growth when using generalized estimating equations (GEE) to estimate a slope and provide intuition for why this possibility exists. We use theoretical and simulation-based results to characterize situations that may result in nonmonotonic information growth. Nonmonotonic information growth is most likely to occur when (1) accrual is fast relative to follow-up on each individual, (2) correlation among measurements from the same individual is high, and (3) measurements are becoming more variable further from randomization. In situations that may lead to nonmonotonic information growth, study designers should plan interim analyses to avoid situations most likely to result in nonmonotonic information growth. 相似文献
95.
《JACC: Cardiovascular Imaging》2019,12(9):1769-1779
ObjectivesThis study sought to evaluate the prognostic value of cardiac magnetic resonance (CMR)-derived mitral annular plane systolic excursion (MAPSE) in a large multicenter population of patients with hypertension.BackgroundIn patients with hypertension, cardiac abnormalities are powerful predictors of adverse outcomes. Long-axis mitral annular movement plays a fundamental role in cardiac mechanics and is an early marker for a number of pathological processes. Given the adverse consequences of cardiac involvement in hypertension, the authors hypothesized that lateral MAPSE may provide incremental prognostic information in these patients.MethodsConsecutive patients with hypertension and a clinical indication for CMR at 4 U.S. medical centers were included in this study (n = 1,735). Lateral MAPSE was measured in the 4-chamber cine view. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the association between lateral MAPSE and death. The incremental prognostic value of lateral MAPSE was assessed in nested models.ResultsOver a median follow-up period of 5.1 years, 235 patients died. By Kaplan-Meier analysis, risk of death was significantly higher in patients with a lateral MAPSE < median (10 mm) (log-rank; p < 0.0001). Lateral MAPSE was associated with risk of death after adjustment for clinical and imaging risk factors (hazard ratio [HR]: 1.402-per-millimeter decrease; p < 0.001). Addition of lateral MAPSE in this model resulted in significant improvement in the C-statistic (0.735 to 0.815; p < 0.0001). Continuous net reclassification improvement was 0.739 (95% confidence interval: 0.601 to 0.902). Lateral MAPSE remained significantly associated with death even after adjustment for feature tracking global longitudinal strain (HR: 1.192-per-millimeter decrease; p < 0.001). Lateral MAPSE was independently associated with death among the subgroups of patients with preserved ejection fraction (HR = 1.339; p < 0.001) and in those without history of myocardial infarction (HR: 1.390; p < 0.001).ConclusionsCMR-derived lateral MAPSE is a powerful, independent predictor of mortality in patients with hypertension and a clinical indication for CMR, incremental to common clinical and CMR risk factors. These findings may suggest a role for CMR-derived lateral MAPSE in identifying hypertensive patients at highest risk of death. 相似文献
96.
97.
目的 探讨SHEL事故分析法在院前急救护理安全管理中的应用效果.方法 应用SHEL事故分析法对2010年1月至2011年12月院前急救护理工作中出现的25例次护理缺陷进行分析,制定护理安全管理措施并进行针对性的管理.结果 加强护理安全管理后,2012年1~12月发生护理缺陷4例次,较管理前(25例次)显著减少(P<0.05).结论 应用SHEL事故分析法对院前急救护理缺陷进行原因分析,针对性的制定护理安全管理措施,能明显降低护理缺陷的发生,保证护理安全. 相似文献
98.
Vanessa Moñivas Palomero Alejandro Durante-Lopez Mario Torres Sanabria Javier Segovia Cubero Jesús González-Mirelis Jorge Vazquez Lopez-Ibor Sara M. Navarro Rico Isabel Krsnik Fernando Dominguez Alejandro Martinez Mingo Francisco J. Hernandez-Perez Gibanel Cavero Susana Mingo Santos 《Journal of the American Society of Echocardiography》2019,32(7):845-853.e1
99.
100.