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   16322篇
  免费   1412篇
  国内免费   72篇
耳鼻咽喉   228篇
儿科学   365篇
妇产科学   238篇
基础医学   1945篇
口腔科学   468篇
临床医学   1783篇
内科学   3741篇
皮肤病学   281篇
神经病学   1207篇
特种医学   766篇
外科学   2451篇
综合类   407篇
现状与发展   30篇
一般理论   16篇
预防医学   1201篇
眼科学   517篇
药学   1095篇
中国医学   43篇
肿瘤学   1024篇
  2023年   223篇
  2021年   205篇
  2020年   157篇
  2019年   216篇
  2018年   266篇
  2017年   216篇
  2016年   251篇
  2015年   308篇
  2014年   484篇
  2013年   732篇
  2012年   855篇
  2011年   935篇
  2010年   573篇
  2009年   565篇
  2008年   910篇
  2007年   1050篇
  2006年   1043篇
  2005年   1010篇
  2004年   1059篇
  2003年   977篇
  2002年   995篇
  2001年   145篇
  2000年   103篇
  1999年   188篇
  1998年   224篇
  1997年   210篇
  1996年   175篇
  1995年   218篇
  1994年   171篇
  1993年   179篇
  1992年   95篇
  1991年   98篇
  1990年   105篇
  1989年   117篇
  1988年   121篇
  1987年   92篇
  1986年   91篇
  1985年   121篇
  1984年   164篇
  1983年   143篇
  1982年   216篇
  1981年   226篇
  1980年   171篇
  1979年   86篇
  1978年   115篇
  1977年   141篇
  1976年   142篇
  1975年   122篇
  1974年   94篇
  1973年   90篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.

Background

Although it is known that women do not participate in trials as frequently as men, there are limited recent data examining how women recruitment has changed over time.

Methods

We conducted MEDLINE search using a validated strategy for randomized trials published in New England Journal of Medicine, Lancet, and Journal of the American Medical Association between 1986 and 2015, and included trials evaluating pharmacologic or nonpharmacologic therapies. We abstracted data on demographics, intervention type, clinical indication, and trial design characteristics, and examined their relationships with women enrollment.

Results

In total, 598 trials met inclusion criteria. Women enrollment increased significantly over time (21% between 1986 and 1990 to 33% between 2011 and 2015; Pfor trend < 0.001) and did not differ by journal or funding source. Women enrollment varied with clinical indication, comprising 37% for non–coronary artery disease vascular trials, 30% for coronary artery disease trials, 28% for heart failure trials, and 28% for arrhythmia trials (P < 0.001), which were all significantly lower than the expected proportion in disease populations (P < 0.001). Women enrollment varied with trial type (31%, 29%, and 26% for pharmacologic, device, and procedural trials, respectively; P = 0.001). These findings were corroborated using multivariable analysis. We found significant positive correlations between women enrolled, and mean age and total number of participants. Fewer women were enrolled in trials reporting statistically significant results than those who did not (P = 0.001).

Conclusions

Although enrollment of women has increased over time, it remains lower than the relative proportion in the disease population. Future studies should elucidate the reasons for persistent under-representation of women in clinical trials.  相似文献   
3.
Background: Intensive blood pressure (BP) lowering may offer protective effects against major adverse cardiac event (MACE) but is also associated with a greater risk of a serious adverse event (SAE). The risk-benefit profile of intensive versus standard BP control has not been comprehensively assessed. Methods: Four studies were identified from a systematic literature search for randomized controlled trials comparing intensive versus standard BP lowering that reported both MACE and SAE endpoints. A previously described statistical approach was applied to characterize the efficacy-safety tradeoff of BP control. The bivariate outcome was computed to quantitatively assess the net clinical benefit (NCB) of intensive BP lowering as compared to standard treatment, with positive values indicating increased risks and negative values indicating decreased risks. Results: Data from the SPRINT trial demonstrated that intensive strategy was superior in MACE but inferior in SAE, thereby eroding the NCB (bivariate outcome: 0.33% [?0.50% to 1.21%]). Intensive strategy from the SPS3 trial fulfilled non-inferiority in both MACE and SAE but did not reach a favorable NCB (?1.31% [?2.25% to 0.01%]). The ACCORD trial suggested that intensive strategy was non-inferior in MACE but inferior in SAE (?0.19% [?0.79% to 1.37%]). Results from the VALISH trial were inconclusive for SAE but suggested non-inferiority in MACE (?1.19% [?3.24% to 0.68%]). Conclusions: Compared to the standard blood pressure target, pooled data from randomized controlled trials suggest that intensive strategy did not achieve a net clinical benefit when weighing the benefit of MACE reduction against the risk of SAE under the bivariate framework.Abbreviations: Blood pressure (BP), diastolic blood pressure (DBP), major adverse cardiac event (MACE), net clinical benefit (NCB), serious adverse event (SAE), systolic blood pressure (SBP).  相似文献   
4.
We report on four children born with medium to large congenital melanocytic nevi (CMN) with color heterogeneity and irregular surface rugosity. As these patients aged, their nevi evolved to become more homogeneous and lighter in color, and developed a smoother, more even texture. We propose that given this evolution toward benignity, conservative monitoring and management may be appropriate even in the context of atypical‐appearing features at birth. Such knowledge regarding the evolution of these CMN can more accurately guide parents and clinicians in determining whether to biopsy or remove an atypical‐looking lesion early in life for medical or cosmetic reasons.  相似文献   
5.
6.
7.
8.
9.
Abstract

Purpose: We examined underlying psychosocial processes of a behavioral treatment for urinary incontinence (UI) of prostate cancer survivors.

Design: Secondary analysis of data collected from a clinical trial.

Sample: Two hundred forty-four prostate cancer survivors who participated in a clinical trial of behavioral intervention to UI as intervention or control subjects.

Methods: The participants had a 3-month behavioral intervention or usual care and were followed up for an additional 3?months. They were assessed at baseline, 3, and 6?months. Latent growth curve models were performed to examine trajectories of each study variable and relationships among the variables.

Findings: Increasing self-efficacy and social support were significantly and independently associated with more reduction of urinary leakage frequency over time.

Implications for psychosocial oncology: Providing problem-solving skills and social support, including peer support, are essential for empowering patients to reduce UI.  相似文献   
10.
Neurological Sciences - The practice of teleneurology provided an accessible and safe method of consultation during the COVID-19 pandemic. We aimed to describe the practice of teleneurology among...  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