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   1695874篇
  免费   123349篇
  国内免费   3781篇
耳鼻咽喉   21733篇
儿科学   55673篇
妇产科学   46157篇
基础医学   241237篇
口腔科学   48744篇
临床医学   151322篇
内科学   333549篇
皮肤病学   38651篇
神经病学   131158篇
特种医学   63919篇
外国民族医学   242篇
外科学   257281篇
综合类   38948篇
现状与发展   4篇
一般理论   531篇
预防医学   124241篇
眼科学   40212篇
药学   123613篇
  7篇
中国医学   4475篇
肿瘤学   101307篇
  2021年   12787篇
  2019年   13531篇
  2018年   19957篇
  2017年   15218篇
  2016年   16623篇
  2015年   18965篇
  2014年   26220篇
  2013年   37952篇
  2012年   52738篇
  2011年   55425篇
  2010年   32774篇
  2009年   30695篇
  2008年   51527篇
  2007年   54802篇
  2006年   55262篇
  2005年   52549篇
  2004年   50751篇
  2003年   48160篇
  2002年   46381篇
  2001年   91789篇
  2000年   93616篇
  1999年   76978篇
  1998年   19728篇
  1997年   17272篇
  1996年   17394篇
  1995年   16745篇
  1994年   15292篇
  1993年   14078篇
  1992年   57388篇
  1991年   55272篇
  1990年   52971篇
  1989年   50750篇
  1988年   46136篇
  1987年   44941篇
  1986年   42232篇
  1985年   39989篇
  1984年   29352篇
  1983年   24909篇
  1982年   13898篇
  1979年   25531篇
  1978年   17577篇
  1977年   14906篇
  1976年   13876篇
  1975年   14566篇
  1974年   17632篇
  1973年   16948篇
  1972年   15675篇
  1971年   14454篇
  1970年   13437篇
  1969年   12523篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
111.
In light of the pharmacophoric structural requirements for achieving anticonvulsant activity, a series of N-(1-methyl-4-oxo-2-un/substituted-1,2-dihydroquinazolin-3[4H]-yl)benzamide (4a-g) and N-(1-methyl-4-oxo-2-un/substituted-1,2-dihydroquinazolin-3[4H]-yl)-2-phenylacetamide (4h-n) derivatives were synthesized in two steps starting from the reaction of N-methyl isatoic anhydride with the appropriate hydrazide and followed by condensation with the appropriate aldehyde. The anticonvulsant activities of the synthesized compounds were evaluated according to the anticonvulsant drug development (ADD) programme protocol. Among the synthesized compounds, 4n showed promising activity in both the maximal electroshock (MES) and pentylenetetrazole (PTZ) tests with median effective dose (ED50) values of 40.7 and 6 mg/kg, respectively. The six most promising derivatives, 4b , 4a , 4c , 4f , 4j , and 4i , showed very low ED50 values in the PTZ test (3.1, 4.96, 8.68, 9.89, 12, and 13.53 mg/kg, respectively). All the tested compounds showed no to low neurotoxicity in the rotarod test with a wide therapeutic index. Docking studies of compound 4n suggested that GABAA binding could be the mechanism of action of these derivatives. The in silico drug likeliness parameters indicated that none of the designed compounds violate Lipinski's rule of five and that they are able to cross the blood–brain barrier.
Hit, Lead & Candidate Discovery
  相似文献   
112.
Renal Denervation for Treatment of Cardiac Arrhythmias . It has now been more than a quarter of a century since modulation of the sympathetic nervous system was proposed for the treatment of cardiac arrhythmias of different origins. But it has also been some time since some of the early surgical attempts have been abandoned. With the development of ablation techniques, however, new approaches and targets have been recently introduced that have revolutionized our way of thinking about sympathetic modulation. Renal nerve ablation technology is now being successfully used for the treatment of resistant hypertension, but the indication spectrum might broaden and new therapeutic options might arise in the near future. This review focuses on the possible impact of renal sympathetic system modulation on cardiac arrhythmias, the current evidence supporting this approach, and the ongoing trials of this method in electrophysiological laboratories. We will discuss the potential roles that sympathetic modulation may play in the future.  相似文献   
113.
114.
115.
116.

Background

Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.

Methods

We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).

Results

Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.

Conclusions

Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation.  相似文献   
117.
118.
119.
120.
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