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   1406224篇
  免费   123172篇
  国内免费   1399篇
  2021年   17810篇
  2019年   16137篇
  2018年   18131篇
  2017年   16930篇
  2016年   28250篇
  2015年   42306篇
  2014年   50349篇
  2013年   76509篇
  2012年   36614篇
  2011年   25501篇
  2010年   43996篇
  2009年   45318篇
  2008年   24258篇
  2007年   22448篇
  2006年   27380篇
  2005年   28749篇
  2004年   27708篇
  2003年   25472篇
  2002年   23575篇
  2001年   39564篇
  2000年   37319篇
  1999年   35522篇
  1998年   25885篇
  1997年   25668篇
  1996年   25061篇
  1995年   23166篇
  1994年   22973篇
  1993年   22139篇
  1992年   30440篇
  1991年   29152篇
  1990年   27418篇
  1989年   28283篇
  1988年   26134篇
  1987年   24559篇
  1986年   23081篇
  1985年   24986篇
  1984年   24155篇
  1983年   21270篇
  1982年   21085篇
  1981年   20233篇
  1980年   18932篇
  1979年   20012篇
  1978年   18678篇
  1977年   17763篇
  1976年   16771篇
  1975年   16637篇
  1974年   17152篇
  1973年   17520篇
  1972年   14901篇
  1971年   13678篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
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   
982.
Correspondenz     
Ohne Zusammenfassung  相似文献   
983.
984.
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   
985.
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   
986.
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   
987.
988.
989.
990.
T S Il'ina 《Genetika》1986,22(11):2572-2582
The published data on molecular mechanisms of transposons movement inside and between genomes are reviewed. The replicative mechanism of transposition of the family of Tn3-like elements is discussed, as well as the modes of bacteriophage Mu, Tn9, Tn10, Tn903 transposition. The factors affecting the choice of transposition pathways are analysed.  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