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   1160424篇
  免费   131779篇
  国内免费   707篇
  1292910篇
  2018年   10221篇
  2016年   13978篇
  2015年   19379篇
  2014年   22786篇
  2013年   32591篇
  2012年   36227篇
  2011年   36673篇
  2010年   24832篇
  2009年   22811篇
  2008年   32594篇
  2007年   33701篇
  2006年   31704篇
  2005年   30648篇
  2004年   30406篇
  2003年   29207篇
  2002年   28249篇
  2001年   50490篇
  2000年   50970篇
  1999年   40936篇
  1998年   14972篇
  1997年   15556篇
  1996年   14738篇
  1995年   14014篇
  1994年   13726篇
  1993年   13535篇
  1992年   34536篇
  1991年   33711篇
  1990年   33055篇
  1989年   32258篇
  1988年   30073篇
  1987年   28401篇
  1986年   26650篇
  1985年   26761篇
  1984年   22418篇
  1983年   19169篇
  1982年   14848篇
  1981年   13514篇
  1980年   12735篇
  1979年   21298篇
  1978年   16619篇
  1977年   15201篇
  1976年   14085篇
  1975年   15746篇
  1974年   16616篇
  1973年   16464篇
  1972年   14999篇
  1971年   13457篇
  1970年   11706篇
  1969年   11172篇
  1968年   10188篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
711.
The effect of the pentapeptide H-Cys-Tyr-Ile-Gln-Asn-OH to act like melanocyte-stimulating hormone-releasing factor (MSH-RF) was studied. This peptide decreases at ng amounts the MSH content of the rat pituitary and increases plasma MSH concentration. This agent also stimulates the release of MSH in animals with eminence lesion, indicating a direct action of the pentapeptide on the gland.  相似文献   
712.
713.
714.
715.
The capillaries of the cardiac muscle were investigated in the goat by means of light microscopy, transmission electron microscopy and scanning electron microscopy, and the following results were obtained. The capillaries of the working cardiac muscles were numerous, arranged mainly parallel to the long axis of muscle cells and formed dense elongated networks. On the contrary, those of the terminal Purkinje fibers were relatively few in number, oriented in various directions and formed loose and circularly meshed networks surrounding the fibers. Such findings were discussed in correlation with the physiology and functional morphology of various types of the cardiac muscle cells.  相似文献   
716.
Five cases of coincident salmonellosis and ulcerative colitis are described. In three the diagnostic combination was recognized late. If corticosteroid therapy is given for the colitis once the combination is recognized, then simultaneous systemic antibiotic cover is advisable. One of the five patients died during corticosteroid therapy alone with salmonella septicaemia due to a usually non-invasive organism.  相似文献   
717.
Seven patients with “coeliac axis compression syndrome” are reported. Five were treated surgically, but only two did well. A survey of 200 healthy adults showed epigastric bruits in 6·5%; only one of these had dyspepsia, though dyspepsia was present in 12·5% overall.Caution is urged in attributing a causal relationship between coeliac axis compression and pain and in proceeding to arteriography when compression is suspected on clinical grounds.  相似文献   
718.
From experience in the Northampton/Kettering area 9 to 10% of all patients in a general hospital requiring care in an intensive therapy unit were aged 12 years or under. Fifty-nine children were admitted to the intensive therapy unit of Northampton General Hospital between May 1967 and August 1969. Of these, 22 had been injured in road traffic accidents, five were surgical emergencies, five had meningitis, four status epilepticus, and four respiratory infections.All of the 30 families interviewed were in favour of their child being admitted to the unit, and none considered that the experience had had any lasting adverse psychological effect on the child. It is suggested that certain carefully selected child patients do benefit from the facilities of an intensive therapy unit, and for this reason such units must be designed, equipped, and staffed with this in mind.  相似文献   
719.
720.
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