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   832篇
  免费   47篇
  879篇
  2024年   3篇
  2023年   11篇
  2022年   12篇
  2021年   22篇
  2020年   19篇
  2019年   27篇
  2018年   37篇
  2017年   32篇
  2016年   38篇
  2015年   36篇
  2014年   31篇
  2013年   89篇
  2012年   62篇
  2011年   60篇
  2010年   34篇
  2009年   38篇
  2008年   51篇
  2007年   48篇
  2006年   54篇
  2005年   34篇
  2004年   31篇
  2003年   20篇
  2002年   12篇
  2001年   7篇
  2000年   6篇
  1999年   6篇
  1998年   9篇
  1997年   3篇
  1996年   13篇
  1995年   4篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   2篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   3篇
  1981年   1篇
  1979年   2篇
  1978年   2篇
  1976年   2篇
  1974年   3篇
  1972年   1篇
排序方式: 共有879条查询结果,搜索用时 0 毫秒
21.
In a basic microeconomic model (joint production and consumer's utility curves) three key optima appear: the best technological mix, the maximum profit point and the consumer's utility optimum. Compromise analysis can help to clarify their connections. This paper and other recent research attempt to specify the conditions which guarantee that these three optima coincide. Thus compromise programming becomes a valuable surrogate of economic optimization.  相似文献   
22.
There is currently much interest in the potential impact of psychological factors on immune responses. An attempt was made to assess the effects of dominant/subordinate polarity in male mice on the cytotoxic activities of their natural-killer (NK) cells. On the basis of repeated agonistic encounters, categories of subordinate and dominat animals were selected. These animals were compared with manipulated controls (introduced to a novel test cage without an opponent on each occasion) and undisturbed controls (who remained in isolation without manipulation). In terms of NK activity, immunosuppression was observed in both dominant and subordinate categories when compared to undisturbed controls. There were, however, no differences between the fighting exposed subjects and the manipulated controls, suggesting that stress accounts for any changes. © 1994 Wiley-Liss, Inc.  相似文献   
23.
Journal of Philosophical Logic - In this article, we will present a number of technical results concerning Classical Logic, ST and related systems. Our main contribution consists in offering a...  相似文献   
24.
In this article we identify three previously unnoticed problems with flexible moral theories, i.e., theories according to which different moral rules apply when there is full compliance and when there is partial compliance. The first problem is that flexible theories are necessarily very complex, which undermines their ability to motivate and guide action. The second problem is that flexible theories allow for a troubling kind of (moral) domination: the duties an agent has depend on other agents' willingness to comply. Finally, flexible theories introduce indeterminacy: it is sometimes impossible to determine which moral rules apply. When agents stand at the threshold—i.e., when a different rule would apply if a single additional act of noncompliance took place—it is impossible to determine which rule should apply.  相似文献   
25.
Attention, Perception, & Psychophysics - Learning and imitating a complex motor action requires to visually follow complex movements, but conscious perception seems too slow for such tasks....  相似文献   
26.
We searched the Internet for expressions linking topics, such as crime, and vehicles, such as disease, as similes (crime is like a disease) and as metaphors (crime is a disease). We counted the number of times the expressions were accompanied by explanations (crime is like a disease because it spreads by direct personal influence). Similes were more likely than metaphors to be accompanied by explanations. Similes may be preferred if a writer wants to express an out-of-the-ordinary relation between the topic and the vehicle.  相似文献   
27.
The authors studied gender differences in response to hypothetical infidelity in Spanish students. Using a forced-choice methodology, the authors asked a sample of 266 participants to indicate which kind of infidelity would be more distressing: emotional or sexual. Men were significantly more distressed by sexual infidelity than were women, and women were significantly more distressed by emotional infidelity than were men. Results supported the hypothesis that particular infidelity types, which resemble adaptive problems that human beings faced in the past, contribute to the psychology of jealousy. The results are consistent with previous cross-cultural research.  相似文献   
28.
29.
30.
The relationship between hopelessness and depression in predicting suicide‐related outcomes varies based on the anticipation of positive versus negative events. In this prospective study of adolescents at elevated risk for suicide, we used two Beck Hopelessness Scale subscales to assess the impact of positive and negative expectations in predicting depression, suicidal ideation, and suicidal behavior over a 2‐ to 4‐year period. In multivariate regressions controlling for depression, suicidal ideation, and negative‐expectation hopelessness, positive‐expectation hopelessness was the only significant predictor of depressive symptoms and suicidal behavior. Clinical interventions may benefit from bolstering positive expectations and building optimism.  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