首页 | 官方网站   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   920163篇
  免费   104083篇
  国内免费   462篇
生物科学   1024708篇
  2016年   10329篇
  2015年   14558篇
  2014年   17181篇
  2013年   24011篇
  2012年   27406篇
  2011年   27869篇
  2010年   19025篇
  2009年   17815篇
  2008年   25453篇
  2007年   26327篇
  2006年   24694篇
  2005年   23697篇
  2004年   23667篇
  2003年   22957篇
  2002年   22423篇
  2001年   39814篇
  2000年   40351篇
  1999年   32114篇
  1998年   12062篇
  1997年   12640篇
  1996年   12019篇
  1995年   11397篇
  1994年   11208篇
  1993年   11095篇
  1992年   27250篇
  1991年   26738篇
  1990年   26190篇
  1989年   25598篇
  1988年   23677篇
  1987年   23111篇
  1986年   21223篇
  1985年   21436篇
  1984年   17670篇
  1983年   15456篇
  1982年   11988篇
  1981年   10675篇
  1980年   10266篇
  1979年   17047篇
  1978年   13697篇
  1977年   12397篇
  1976年   11636篇
  1975年   12884篇
  1974年   14028篇
  1973年   13694篇
  1972年   12417篇
  1971年   11494篇
  1970年   9887篇
  1969年   9395篇
  1968年   8478篇
  1967年   7687篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Reconstruction of bony structures of the face is always a problem as big as the defect and the function that must be replaced. Everything from simple grafts to sophisticated distant bone flaps has been used. Based on the studies of Cutting et al., Psillakis et al., and Casanova et al., we have developed the full-thickness galeoparietal bone flap, initially for mandibular reconstruction, but of great use for all maxillofacial reconstructions. From July of 1987 to December of 1988, 14 patients have been operated on. The experience with this flap is shown in four patients as follows: primary reconstruction of a mandible as a result of ameloblastoma, secondary reconstruction of a mandible with associated old fractures and malalignment of segments, bilateral malar reconstruction in a patient with Treacher Collins syndrome, and severe sequelae of an already treated Romberg case. Small variations could be made to best accommodate the technique used to the defect we were treating. Some technical details, the experience, the results, and possible sequelae or complications are also discussed.  相似文献   
82.
Trigger finger is a relatively common clinical entity, most frequently caused by stenosing tenosynovitis. Several other conditions not related to tenosynovitis also have been described as a cause of triggering, and these have been reviewed. We present a rare anomaly of the fourth lumbrical muscle insertion as a cause of triggering of the right little finger. This was completely relieved following excision of the anomalous muscle. This rare anatomic variant should be added to the list of potential causes of trigger finger.  相似文献   
83.
84.
    
Ohne Zusammenfassung  相似文献   
85.
86.
87.
88.
89.
90.
Isopropanol administered in a large (6 g/kg, orally) as well as in a lower dose (1 g/kg, I.P.) is slowly oxidized into acetone by the intact rat. Using two inhibitors, 3 amino-1,2,4-triazole and pyrazole, investigations on the hepatic enzymatic system involved in the oxidation of isopropanol show that catalase does not play an important part in this pathway, contrary to alcohol dehydrogenase which is the major enzyme responsible for this oxidation. Although isopropanol oxidation is mainly catalysed in the liver through alcohol dehydrogenase, no alteration of the hepatic extramitochondrial redox state occurs after the administration of a large as well as of a lower dose of isopropanol. From these experiments it may be concluded that alterations of the liver NAD+/NADH ratio, which seem to play an important part in the ethanol induced fatty liver, are not involved in the isopropanol induced one.  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-23

京公网安备 11010802026262号