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   190962篇
  免费   8416篇
  国内免费   155篇
  2020年   2809篇
  2019年   3480篇
  2018年   3852篇
  2017年   4196篇
  2016年   4870篇
  2015年   3966篇
  2014年   4826篇
  2013年   23554篇
  2012年   5325篇
  2011年   4639篇
  2010年   4230篇
  2009年   4942篇
  2008年   4673篇
  2007年   4265篇
  2006年   4649篇
  2005年   4513篇
  2004年   4078篇
  2003年   3665篇
  2002年   3437篇
  2001年   4247篇
  2000年   4033篇
  1999年   3693篇
  1998年   2931篇
  1997年   2719篇
  1996年   2644篇
  1995年   2472篇
  1994年   2446篇
  1993年   2388篇
  1992年   3027篇
  1991年   2865篇
  1990年   2708篇
  1989年   2606篇
  1988年   2560篇
  1987年   2514篇
  1986年   2543篇
  1985年   2776篇
  1984年   2726篇
  1983年   2483篇
  1982年   2444篇
  1981年   2397篇
  1980年   2253篇
  1979年   2460篇
  1978年   2327篇
  1977年   2253篇
  1976年   2061篇
  1975年   2195篇
  1974年   2318篇
  1973年   2213篇
  1972年   1795篇
  1971年   1720篇
排序方式: 共有10000条查询结果,搜索用时 116 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