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   759995篇
  免费   92221篇
  国内免费   324篇
  852540篇
  2016年   8005篇
  2015年   11054篇
  2014年   13382篇
  2013年   18728篇
  2012年   20978篇
  2011年   21237篇
  2010年   14112篇
  2009年   13332篇
  2008年   19128篇
  2007年   19992篇
  2006年   18948篇
  2005年   18251篇
  2004年   18114篇
  2003年   17594篇
  2002年   17022篇
  2001年   35653篇
  2000年   36241篇
  1999年   28506篇
  1998年   9669篇
  1997年   10212篇
  1996年   9693篇
  1995年   9264篇
  1994年   9167篇
  1993年   9179篇
  1992年   24222篇
  1991年   24034篇
  1990年   23383篇
  1989年   22757篇
  1988年   21221篇
  1987年   20224篇
  1986年   18747篇
  1985年   18876篇
  1984年   15552篇
  1983年   13630篇
  1982年   10299篇
  1981年   9490篇
  1980年   8989篇
  1979年   15168篇
  1978年   11786篇
  1977年   10824篇
  1976年   10056篇
  1975年   11250篇
  1974年   11799篇
  1973年   11635篇
  1972年   10753篇
  1971年   9563篇
  1970年   8419篇
  1969年   7987篇
  1968年   7224篇
  1967年   6332篇
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
61.
62.
63.
Over the past 10 years the AIDS crisis has produced a large volume of writing. Much of this is documentary. Dozens of studies of AIDS from various clinical and political perspectives have been complemented by just as many published diaries, autobiographies, novels, plays, and poems. A few of these works have risen to the surface not only as extraordinarily valuable testimonies to the changes AIDS has wrought in individual and collective life but also as first-rate literary works, worth reading because beyond their immediate purposes they articulate with extraordinary lucidity and compassion some deep truths about the human--and the modern--condition. Paul Monette's Borrowed Time is among the most distinctive of those. It speaks not only for the community of people with AIDS and those who support them but for a generation.  相似文献   
64.
65.
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   
66.
67.
68.
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   
69.
70.
The Saccharomyces cerevisiae SSU1 gene was isolated based on its ability to complement a mutation causing sensitivity to sulfite, a methionine intermediate. SSU1 encodes a deduced protein of 458 amino acids containing 9 or 10 membrane-spanning domains but has no significant similarity to other proteins in public databases. An Ssu1p-GEP fusion protein was localized to the plasma membrane. Multicopy suppression analysis, undertaken to explore relationships among genes previously implicated in sulfite metabolism, suggests a regulatory pathway in which SSU1 acts downstream of FZF1 and SSU3, which in turn act downstream of GRR1.  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