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   23417篇
  免费   191篇
  2024年   8篇
  2023年   52篇
  2022年   55篇
  2021年   71篇
  2020年   106篇
  2019年   97篇
  2018年   3639篇
  2017年   2972篇
  2016年   2385篇
  2015年   283篇
  2014年   183篇
  2013年   488篇
  2012年   804篇
  2011年   2616篇
  2010年   2640篇
  2009年   1525篇
  2008年   1917篇
  2007年   2311篇
  2006年   197篇
  2005年   306篇
  2004年   247篇
  2003年   177篇
  2002年   111篇
  2001年   54篇
  2000年   84篇
  1999年   45篇
  1998年   32篇
  1997年   37篇
  1996年   18篇
  1995年   3篇
  1994年   15篇
  1993年   9篇
  1992年   12篇
  1991年   7篇
  1990年   20篇
  1989年   9篇
  1988年   7篇
  1987年   9篇
  1985年   6篇
  1981年   6篇
  1978年   3篇
  1976年   3篇
  1974年   6篇
  1972年   2篇
  1971年   2篇
  1969年   2篇
  1968年   3篇
  1966年   4篇
  1965年   3篇
  1962年   2篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
111.
112.
113.
The purpose of the study was to investigate cultural changes in a Norwegian airline company over a time span of 10 years. A questionnaire including parameters characterizing culture was administered to air crews in 1986 (n = 137) and in 1996 (n = 50). The performance part of a simulator study in 1996 indicated a significant reduction in operational failures compared with the 1986 study. The data further demonstrated significant changes in cultural variables, such as reduced Dominance and Masculinity, and improved Social climate and Communication. The direction of change in scores on the cultural variables corresponded with the principles on which the remedial actions were based.  相似文献   
114.
Gutiérrez  G.  de Guzmán  I. P.  Martínez  J.  Ojeda-Aciego  M.  Valverde  A. 《Studia Logica》2002,72(1):85-112
The tree-based data structure of -tree for propositional formulas is introduced in an improved and optimised form. The -trees allow a compact representation for negation normal forms as well as for a number of reduction strategies in order to consider only those occurrences of literals which are relevant for the satisfiability of the input formula. These reduction strategies are divided into two subsets (meaning- and satisfiability-preserving transformations) and can be used to decrease the size of a negation normal form A at (at most) quadratic cost. The reduction strategies are aimed at decreasing the number of required branchings and, therefore, these strategies allow to limit the size of the search space for the SAT problem.  相似文献   
115.
In the first part of this paper we review evidence suggesting that there exists a mechanism that selects input on the basis of its similarity to the required action. This response-based input selection differs from the more established space- and object-based input selection in that it is not constrained by the structure of the input. Our evidence suggests that the two-choice Stroop effect is caused by this response-based selection mechanism. By contrast, it is known that the flanker effect is determined by the space- and object- based selection mechanisms. We explore whether the conflict resolution of the Stroop and flanker tasks is different as well by embedding these two tasks in a PRP (Psychological Refractory Period) paradigm. We show that the Stroop and the PRP effects are additive whereas the flanker and the PRP effects are underadditive, suggesting that the processes in charge of the conflict resolution in the Stroop and the flanker tasks are indeed different. We discuss possible reasons for this difference, and discuss possible ways in which the response-based mechanism can be implemented in information processing models.  相似文献   
116.
In a pair of experiments, we have compared the ability of changes of place (Exp. 1) and changes of time of day (Exp. 2) to separately modulate learned saline-aversion memory phenomena in rats. Neither a spatial nor a temporal change disrupted latent inhibition using the present behavioral procedure. However, pre-exposure to the taste increased the contextual control of the learned aversion expression. The aversion reappeared in the place or at the time of conditioning after extinction in a different context. The results indicate that environmental and temporal contexts can independently, but similarly modulate taste aversion learning.  相似文献   
117.
Numerous previous investigators have explained species differences in spatial memory performance in terms of differences in foraging ecology. In three experiments we attempted to extend these findings by examining the extent to which the spatial memory performance of echidnas (or "spiny anteaters") can be understood in terms of the spatio-temporal distribution of their prey (ants and termites). This is a species and a foraging situation that have not been examined in this way before. Echidnas were better able to learn to avoid a previously rewarding location (to "win-shift") than to learn to return to a previously rewarding location (to "win-stay"), at short retention intervals, but were unable to learn either of these strategies at retention intervals of 90 min. The short retention interval results support the ecological hypothesis, but the long retention interval results do not. Electronic Publication  相似文献   
118.
A comparative analysis was conducted of five different methods for scoring the Rod-and-Frame Test to examine the convergent validities of each of the five methods with performance on the Embedded Figures Test for a sample of 408 13- to 16-yr.-olds. The scoring methods included the absolute error, the algebraic error, the absolute value of the algebraic error, the frame effect, and an assessment of relative field dependence. Correlations obtained among the five methods and the Embedded Figures Test indicated different patterns for boys and girls. In general, the method which employed the absolute value of the algebraic error yielded the strongest convergent validity coefficients with scores on the Embedded Figures Test and Group Embedded Figures Test for boys (.62 and -.54, respectively), although, for girls, the absolute algebraic error and absolute error both yielded coefficients of .50 with Embedded Figures Test scores and -.46 with Group Embedded Figures Test scores.  相似文献   
119.
Current general health belief measures that are used to assess health behaviors do not capture the full range of health beliefs present among Latinos. The purpose of this study was to develop a reliable and valid measure of Latino health beliefs, the Cultural Health Attributions Questionnaire (CHAQ). Three hundred forty participants were recruited in 2 metropolitan areas with large Latino populations. Exploratory factor analysis revealed 2 highly interpretable 12-item subscales: the Equity Attribution and the Behavioral-Environmental Attribution scales. Examination of the relationships between the subscales and measures of acculturation provided evidence of construct validity. Moreover, the prediction of health care behavior by the CHAQ also indicated initial criterion validity.  相似文献   
120.
Confirmatory factor analysis and regression analyses of the Beavers Interactional Scales did not appear to support the model offered by its developers, namely, several specified family attributes contributing respectively to two global factors of Family Competence and Family Style. Moreover, regression analysis indicated that only three of 12 items predicted raters' assessments of Global Family Health, and one of seven items predicted Global Family Style. Individuals interested in the family dynamic centripetal/centrifugal might best think of that as a unitary entity and rate it accordingly.  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