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   1346107篇
  免费   115420篇
  国内免费   6404篇
耳鼻咽喉   16770篇
儿科学   43331篇
妇产科学   36860篇
基础医学   185096篇
口腔科学   36447篇
临床医学   121822篇
内科学   280412篇
皮肤病学   32110篇
神经病学   111669篇
特种医学   55856篇
外国民族医学   274篇
外科学   211161篇
综合类   31602篇
现状与发展   2篇
一般理论   415篇
预防医学   107431篇
眼科学   28403篇
药学   94275篇
  5篇
中国医学   2252篇
肿瘤学   71738篇
  2018年   13720篇
  2017年   10916篇
  2016年   13107篇
  2015年   14630篇
  2014年   20364篇
  2013年   30364篇
  2012年   37123篇
  2011年   39798篇
  2010年   24848篇
  2009年   24281篇
  2008年   37052篇
  2007年   39487篇
  2006年   40518篇
  2005年   39020篇
  2004年   37237篇
  2003年   36295篇
  2002年   34326篇
  2001年   66102篇
  2000年   67962篇
  1999年   56659篇
  1998年   16807篇
  1997年   15076篇
  1996年   16061篇
  1995年   16273篇
  1994年   15135篇
  1993年   14188篇
  1992年   47131篇
  1991年   45782篇
  1990年   43985篇
  1989年   41837篇
  1988年   38777篇
  1987年   38108篇
  1986年   35869篇
  1985年   34659篇
  1984年   26383篇
  1983年   22127篇
  1982年   13876篇
  1981年   12477篇
  1980年   11745篇
  1979年   23559篇
  1978年   17096篇
  1977年   14402篇
  1976年   13199篇
  1975年   13737篇
  1974年   16110篇
  1973年   15405篇
  1972年   14180篇
  1971年   13045篇
  1970年   11885篇
  1969年   11110篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
131.
132.

Introduction/Hypothesis

Recruitment of participants into phase 1 vaccine clinical trials can be challenging since these vaccines have not been used in humans and there is no perceived benefit to the participant. Occasionally, as was the case with a phase 1 clinical trial of an Ebola vaccine in Halifax, Canada, during the 2014–2016 West African Ebola virus outbreak, recruitment is less difficult. In this study, we explored the motivations of participants in two phase 1 vaccine trials that were concurrently enrolling at the same centre and compared the motivations of participants in a high-profile phase 1 Ebola vaccine trial to those in a less high-profile phase 1 adjuvanted seasonal influenza vaccine study.

Methods

An online survey which included participants’ prior experience with clinical trials, motivations to participate (including financial incentives), and demographic information was developed to examine the motivations of healthy participants in two phase 1 clinical vaccine trials conducted at the Canadian Center for Vaccinology in Halifax, Nova Scotia. Participants were invited via email to complete the online survey. Readability and clarity were assessed through pilot testing.

Results

A total of 49 (55.7%) of 88 participants of the two studies completed the survey (22 [55%] of 40 participants from the Ebola vaccine study and 27 [56.3%] of 48 from the adjuvanted influenza vaccine study). Motivations that were most frequently ranked among participants' top three in both trials were (1) wanting to contribute to the health of others, (2) wanting to participate in something important, (3) wanting to contribute to the advancement of science, and (4) wanting to receive an incentive such as money or a tablet.

Conclusions/Recommendations

Although media attention and financial compensation were more often cited by Ebola vaccine trial participants as a reason to participate, both altruistic and self-interested factors were important motivations for participants in their decision to participate in a phase 1 vaccine clinical trial.  相似文献   
133.
134.
Deep brain stimulation (DBS) in psychiatric illnesses has been clinically tested over the past 20 years. The clinical application of DBS to the superolateral branch of the medial forebrain bundle in treatment‐resistant depressed patients—one of several targets under investigation—has shown to be promising in a number of uncontrolled open label trials. However, there are remain numerous questions that need to be investigated to understand and optimize the clinical use of DBS in depression, including, for example, the relationship between the symptoms, the biological substrates/projections and the stimulation itself. In the context of precision and customized medicine, the current paper focuses on clinical and experimental research of medial forebrain bundle DBS in depression or in animal models of depression, demonstrating how clinical and scientific progress can work in tandem to test the therapeutic value and investigate the mechanisms of this experimental treatment. As one of the hypotheses is that depression engenders changes in the reward and motivational networks, the review looks at how stimulation of the medial forebrain bundle impacts the dopaminergic system.  相似文献   
135.
Bulletin of Experimental Biology and Medicine - Fast neutron therapy, which previously has demonstrated effective results, but along with a large number of complications, can again be considered a...  相似文献   
136.

Background

Bone mineral density (BMD) has been found to improve after parathyroidectomy (PTX) in patients with primary hyperparathyroidism. There are few data on the effect of PTX on BMD in normocalcemic and normohormonal primary hyperparathyroidism.

Methods

A retrospective analysis of 92 primary hyperparathyroidism patients who underwent PTX between 2004 and 2012 with pre- and post-PTX dual-energy x-ray absorptiometry was performed. Within-person changes in BMD pre- and post-PTX were analyzed using log linear mixed models, stratified by biochemical status.

Results

Bone mineral density increased post-PTX in the whole cohort at the lumbar spine (+2.5%), femoral neck (+2.1%), and total hip (+1.9%) and decreased at the one-third radius (–0.9%). On comparison of BMD changes by profile, BMD increased in those with the typical profile at the lumbar spine (3.2%), femoral neck (2.9%), and total hip (2.9%) but declined at the one-third radius (–1.5%). In contrast, BMD improved only at the femoral neck (4.3%) in the normohormonal group and did not change at any site in the normocalcemic group. The typical group had a greater increase in BMD over time at the femoral neck and total hip compared with normocalcemic patients.

Conclusion

Our results indicate that the skeletal benefit of PTX was attenuated in normocalcemic and normohormonal patients, suggesting that skeletal changes after PTX may depend on biochemical profile.  相似文献   
137.
138.
139.
140.
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