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   2304篇
  免费   187篇
  国内免费   1篇
耳鼻咽喉   22篇
儿科学   92篇
妇产科学   34篇
基础医学   382篇
口腔科学   21篇
临床医学   347篇
内科学   526篇
皮肤病学   30篇
神经病学   151篇
特种医学   62篇
外科学   205篇
综合类   29篇
一般理论   2篇
预防医学   235篇
眼科学   40篇
药学   136篇
中国医学   3篇
肿瘤学   175篇
  2021年   25篇
  2020年   10篇
  2019年   30篇
  2018年   34篇
  2017年   18篇
  2016年   33篇
  2015年   34篇
  2014年   46篇
  2013年   64篇
  2012年   165篇
  2011年   133篇
  2010年   67篇
  2009年   43篇
  2008年   143篇
  2007年   136篇
  2006年   155篇
  2005年   150篇
  2004年   108篇
  2003年   96篇
  2002年   92篇
  2001年   45篇
  2000年   60篇
  1999年   41篇
  1998年   22篇
  1997年   27篇
  1996年   22篇
  1995年   20篇
  1994年   12篇
  1993年   17篇
  1992年   52篇
  1991年   51篇
  1990年   45篇
  1989年   44篇
  1988年   42篇
  1987年   39篇
  1986年   38篇
  1985年   36篇
  1984年   33篇
  1983年   27篇
  1982年   28篇
  1981年   22篇
  1979年   19篇
  1978年   15篇
  1977年   11篇
  1976年   12篇
  1975年   11篇
  1974年   14篇
  1973年   16篇
  1968年   12篇
  1967年   11篇
排序方式: 共有2492条查询结果,搜索用时 15 毫秒
991.
Age-friendly college campuses offer opportunities for lifelong learning for students of all ages. University-based retirement communities are especially well aligned with this goal by allowing residents to enroll in college courses. Although this arrangement is a standard educational option for college-linked communities, it can have challenges. In particular, the semester-long schedule may be inconvenient for many older students. The Talk of Ages intergenerational module program described in this case study was designed to offer an alternative curricular format to bring older and younger students together for 1 to 2 weeks in focused course activities. To encourage participation across the curriculum, instructors were urged to draw on existing course content. Initial feedback about the program indicated that instructors as well as older and younger students found the program appealing. Useful suggestions for refining the program were also revealed.  相似文献   
992.
993.
994.
995.
996.
997.
998.
The purpose of this study was to determine the site of action in the CNS responsible for producing picrotoxin-induced sympathetic mediated increase in coronary vascular resistance. To do this, picrotoxin, was administered either into the lateral cerebral ventricle, with the perfusion restricted to the forebrain, or into the fourth ventricle, to perfuse only the hindbrain and spinal cord, in chloralose-anesthetized cats, while monitoring coronary blood flow from the anterior descending branch of the left coronary artery, arterial pressure, heart rate and electrocardiogram (ECG). There was no difference between administration into the forebrain and hind-brain in terms of changes in coronary vascular resistance, ECG, arterial pressure and sinus rate when 600 micrograms of picrotoxin was used. Administration into either area elicited significant increases in coronary vascular resistance, arterial pressure and sinus rate, as well as changes in the ST segment and occasional ventricular tachyarrhythmias. However, a separation of effects was noted between the forebrain and the hindbrain when 200 micrograms of picrotoxin was administered. Administration of this dose into the forebrain did not significantly alter coronary vascular resistance or the ST segment, although significant increases in arterial pressure and sinus rate occurred in these animals. In contrast, administration of this dose into the hindbrain elicited significant increases in coronary vascular resistance, ST segment, arterial pressure and sinus rate. These results indicate that the most sensitive site for eliciting picrotoxin-induced increase in coronary vascular lies in the hindbrain.  相似文献   
999.
Glucocorticoids and immune responses.   总被引:6,自引:0,他引:6  
  相似文献   
1000.
A stimulation of distal colonic motor activity was produced in anesthetized cats following intravenous administration of cholecystokinin. The contractile response elicited by cholecystokinin was not reduced following pretreatment with atropine. However, when animals were treated with agents which increased the net cholinergic input to the colon, a marked exaggeration of the subsequent cholecystokinin-induced response occurred. This cholinergically mediated exaggeration was produced following administration of the cholinergic agonist bethanechol, or after removal of tonic inhibitory systems mediated by prostaglandin or alpha-adrenergic input, whose blockade results in atropine-sensitive colonic stimulation. Cholecystokinin was also found to produce stimulation of motor activity in the pylorus, jejunum, proximal colon and gallbladder. Cholinergically mediated exaggeration of the cholecystokinin response was also present in the pylorus and proximal colon, but not gallbladder or jejunum. An inhibition of spontaneous motor activity was produced in the ileum or duodenum following cholecystokinin administration.  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