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   190817篇
  免费   8407篇
  国内免费   214篇
  2020年   2813篇
  2019年   3479篇
  2018年   3846篇
  2017年   4166篇
  2016年   4860篇
  2015年   3963篇
  2014年   4830篇
  2013年   23533篇
  2012年   5306篇
  2011年   4640篇
  2010年   4233篇
  2009年   4959篇
  2008年   4690篇
  2007年   4267篇
  2006年   4655篇
  2005年   4515篇
  2004年   4080篇
  2003年   3645篇
  2002年   3427篇
  2001年   4248篇
  2000年   4036篇
  1999年   3693篇
  1998年   2925篇
  1997年   2718篇
  1996年   2645篇
  1995年   2467篇
  1994年   2438篇
  1993年   2386篇
  1992年   3029篇
  1991年   2863篇
  1990年   2710篇
  1989年   2605篇
  1988年   2560篇
  1987年   2516篇
  1986年   2547篇
  1985年   2776篇
  1984年   2726篇
  1983年   2478篇
  1982年   2441篇
  1981年   2396篇
  1980年   2252篇
  1979年   2458篇
  1978年   2330篇
  1977年   2247篇
  1976年   2061篇
  1975年   2192篇
  1974年   2317篇
  1973年   2211篇
  1972年   1794篇
  1971年   1719篇
排序方式: 共有10000条查询结果,搜索用时 421 毫秒
111.
112.
113.
Some languages create the impression of being stress timed. Claims have been made that this timing of stressed syllables enables the listener to predict the future locations of informative parts later in a sentence. The fact that phoneme monitoring is delayed when targets in a spoken sentence are displaced has been taken as supporting this claim (Meltzer, Martin, Bergfeld Mills, Imhoff and Zohar, 1976). In the present study temporal displacement was induced without introducing phonetic discontinuities. In Dutch sentences a word just in advance of a target-bearing word was replaced by another one differing in length. Results show that the temporal displacement per se did not have any effect on phoneme-monitoring reaction times. Implications for a theory of fpeech processing are discussed.  相似文献   
114.
The ability of two species of tits to remember the location and/or features of an object was tested in a delayed-matching-to-sample procedure. Three values of retention interval between presentation of the sample stimulus and the choice--30 sec, 5 min, and 15 min--were used. Both species performed at above-chance level at all retention intervals, and there was no significant decline in accuracy with increasing interval. A pool of 100 stimulus objects was used, but the results of control trials indicated that the birds responded primarily to location rather than stimulus features of the object itseif. Although the food-storing marsh tit tended to perform at a higher level than the non-storing great tit, the only significant difference between the species was in the first 50 trials of the first treatment, when the birds were acquiring the task. The results are discussed in relation to the hypothesized special memory capacity of food-storing birds.  相似文献   
115.
116.
117.
118.
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   
119.
120.
Most studies of suicide in younger patients have demonstrated significant alterations in the serotonin system. Although a high percentage of completed suicides occur in late-life, to date very few studies of the biology of suicide have focused on this age group. This chapter describes age-related changes in the central nervous system pertinent to the biology of suicide, then reviews post-mortem biological studies of the brains of suicides and suicide attempters. As suicide attempts in the elderly are characterized by the use of violent means, biologic studies of impulsive violence are discussed. Finally we describe data on the effect of degenerative diseases on the serotonin system and the possible link to increased suicidal behavior in affected patients. This review underscores the need for further study of the biology of suicide in the geriatric age group.  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