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   52971篇
  免费   1381篇
  国内免费   9篇
  54361篇
  2020年   330篇
  2019年   473篇
  2018年   3947篇
  2017年   3282篇
  2016年   2774篇
  2015年   624篇
  2014年   626篇
  2013年   2511篇
  2012年   1536篇
  2011年   3367篇
  2010年   3053篇
  2009年   2058篇
  2008年   2582篇
  2007年   2995篇
  2006年   879篇
  2005年   972篇
  2004年   917篇
  2003年   775篇
  2002年   757篇
  2001年   1051篇
  2000年   982篇
  1999年   728篇
  1998年   407篇
  1997年   329篇
  1996年   315篇
  1992年   552篇
  1991年   542篇
  1990年   534篇
  1989年   539篇
  1988年   533篇
  1987年   497篇
  1986年   523篇
  1985年   573篇
  1984年   455篇
  1983年   432篇
  1982年   355篇
  1981年   339篇
  1979年   523篇
  1978年   380篇
  1976年   360篇
  1975年   435篇
  1974年   488篇
  1973年   510篇
  1972年   411篇
  1971年   385篇
  1970年   380篇
  1969年   412篇
  1968年   488篇
  1967年   423篇
  1966年   425篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
15.
As the complexity of the challenges presented by our interactions with our planet continues to grow, we must develop new modes of knowledge production. In these modes, distinctions between multidisciplinary and inter-disciplinary activities and processes have renewed importance. There are at least two distinct types of interdisciplinary activities distinguished by the disciplinary breadth they attempt to bridge. In the narrow case, reductionist processes reveal a common underlying principle or process which can serve as a Rosetta stone. In the broad case, no such common arbiter exists. Investigators must develop integrating vocabulary in the context of the full breadth of their work. His primary activities are the fostering of university-wide interdisciplinary research and curriculum programs focused on global change with the goal of developing Columbia into a world leader in issues related to global stewardship.  相似文献   
16.
17.
18.
19.
Brain mapping studies using dynamic imaging methods demonstrate areas regional cerebral blood flow (rCBF) decreases, as well as areas where increases, during performance of various experimental tasks. Task holds for both sets of cerebral blood flow changes (CBF), providing the opportunity to investigate areas that become and “activated” in the experimental condition relative to control state. Such data yield the intriguing observation that in areas in emotional processing, such as the amygdala, the posteromedial cortex, and the ventral anterior cingulate cortex, although flow as expected during specific emotion-related tasks, flow decreases performance of some attentionally demanding, cognitive tasks. Conversely, in some of the areas that appear to subserve cognitive functions, as the dorsal anterior cingulate and the dorsolateral prefrontal cortices, increases while performing attentionally demanding cognitive tasks, but during some experimentally induced and pathological emotional Although the specific nature of such reciprocal patterns of regional remains unclear, they may reflect an important cross-modal interaction during mental operations. The possibility that neural activity is less in areas required in emotional processing during some higher cognitive processes holds implications for the mechanisms underlying interactions cognition and emotion. Furthermore, the possibility that neural in some cognitive-processing areas is suppressed during intense states suggests mechanisms by which extreme fear or severe may interfere with cognitive performance.  相似文献   
20.
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