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   15001篇
  免费   175篇
  国内免费   3篇
  2019年   58篇
  2018年   1592篇
  2017年   1424篇
  2016年   1038篇
  2015年   99篇
  2014年   77篇
  2013年   457篇
  2012年   428篇
  2011年   1240篇
  2010年   1207篇
  2009年   714篇
  2008年   943篇
  2007年   1223篇
  2006年   139篇
  2005年   216篇
  2004年   183篇
  2003年   145篇
  2002年   141篇
  2001年   230篇
  2000年   230篇
  1999年   147篇
  1998年   62篇
  1997年   57篇
  1996年   64篇
  1993年   55篇
  1992年   118篇
  1991年   120篇
  1990年   121篇
  1989年   101篇
  1988年   89篇
  1987年   97篇
  1986年   108篇
  1985年   105篇
  1984年   95篇
  1983年   83篇
  1979年   95篇
  1978年   70篇
  1977年   62篇
  1976年   55篇
  1975年   67篇
  1974年   92篇
  1973年   100篇
  1972年   72篇
  1971年   69篇
  1970年   80篇
  1969年   75篇
  1968年   106篇
  1967年   82篇
  1966年   93篇
  1958年   62篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
152.
153.
154.
A study is reported in which the relations among normal aging, source amnesia, and frontal lobe functioning were explored. Twenty-four older adults (aged 60-84 years) were tested on their ability to remember where they had acquired new factual information; they were also given the Wisconsin Card Sorting Test (WCST), a test of verbal fluency, and other psychometric tests. The degree of source amnesia in this normal sample correlated with age, verbal fluency, and some measures from the WCST. Source amnesia was not related to Performance IQ, however, or to a measure of fact recall. The implications for the relations among aging, memory, and frontal lobe functions are discussed.  相似文献   
155.
Critical Flicker Fusion Thresholds (CFFTs) were measured in 644 elderly people identified from community-based general practice records, and the relationship of CFFT with age was investigated. The CFFT was measured using the method of limits with mean scores for three ascending (flicker/fusion) and three descending (fusion/flicker) presentations being recorded. The difference between the ascending and descending means was found to be significantly correlated with age (r=−0.131,P<0.001) and may reflect a reduced sensitivity of the Central Nervous System to suprathreshold flicker with increasing age. The results suggest that CFFT measurement has an important role to play in gerontological research as an objective measure of cognitive aspects of the ageing process.  相似文献   
156.
In this article the perspective shifts to the “upstream” end of the agricultural knowledge and information system (AKIS). Because knowledge policy and strategic decision-making are not the prerogative of the public sector, organizations such as cooperative unions and multinational companies are included. After considering the influence of the changing environment on the nature of the AKIS, the role of knowledge management and policy in the emerging knowledge and information market is examined. Special attention is given to public and private R&D. The article then looks where information technology (IT) fits in and what considerations determine strategic investment in IT projects and sustained services. Some of the European experiences with this strategic investment are evaluated.  相似文献   
157.
158.
Abstract— In our discussion of the articles in this Special Section, we ask how well the various methods employed in these investigations can be made to converge on a common issue. We review how current evidence from positron emission tomography, studies of event-related potentials, cognitive methods, lesion studies, and network models relates to the mental processing of an ambiguous word. While many puzzles remain, we are impressed by the promising possibility of bringing these different methods together to deal with an issue central to cognition.  相似文献   
159.
Private and public sector managers were compared regarding their job characteristics and organizational commitment. We hypothesized that job characteristics would be positively related to commitment and that sector would moderate that relationship. Moderated regression analyses revealed partial support for both hypotheses. The existence of clarity and challenge were positively related to commitment. Job characteristics demonstrated a stronger relationship with commitment among private sector managers. Explanations for these findings and directions for future research are discussed.  相似文献   
160.
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