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   29009篇
  免费   976篇
  国内免费   12篇
  2019年   296篇
  2018年   377篇
  2017年   411篇
  2016年   471篇
  2015年   376篇
  2014年   400篇
  2013年   2169篇
  2012年   777篇
  2011年   788篇
  2010年   523篇
  2009年   523篇
  2008年   742篇
  2007年   712篇
  2006年   609篇
  2005年   589篇
  2004年   547篇
  2003年   570篇
  2002年   600篇
  2001年   745篇
  2000年   722篇
  1999年   531篇
  1998年   306篇
  1997年   282篇
  1992年   517篇
  1991年   494篇
  1990年   503篇
  1989年   491篇
  1988年   437篇
  1987年   452篇
  1986年   480篇
  1985年   518篇
  1984年   460篇
  1983年   411篇
  1982年   320篇
  1981年   348篇
  1980年   273篇
  1979年   469篇
  1978年   336篇
  1977年   314篇
  1976年   298篇
  1975年   423篇
  1974年   476篇
  1973年   497篇
  1972年   415篇
  1971年   404篇
  1970年   378篇
  1969年   406篇
  1968年   495篇
  1967年   479篇
  1966年   455篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Stimulus-independent thoughts (SITs) are streams of thoughts and images unrelated to immediate sensory input. Four experiments examined the contribution of aspects of working memory to production of SITs. In Experiments 1 and 2, interventions that were targeted on, respectively, phonological and visuospatial components of working memory both interfered with production of SITs, but there was evidence that these tasks also made demands on central executive resources. Experiments 3 and 4 specifically examined the hypothesis that production of SITs and control of nonproceduralized tasks both depend on central executive resources, and so should show mutual interference. In Experiment 3, prior practice on pursuit rotor and memory tasks reduced the interference with SITs from concurrent task performance. In Experiment 4, randomness within a task involving random-number generation was less when SITs were being produced concurrently than it was when they were not. The results suggest that production of SITs depends on central executive resources.  相似文献   
992.
The literature is reviewed to define a sense of community in the workplace and to identify factors that may foster it. A model is developed and estimated with survey data from a culturally diverse sample of men and women performing lower-level jobs at a medium-sized manufacturing firm. Results of regression analyses are reported that correct for sample selection bias resulting from the lower response rates of minority workers. Findings suggest that well-designed jobs and supportive workplace relationships and policies are important in explaining workers' sense of community, defined as workers' perceptions of mutual commitment between employee and employer. Informal sources of support play a larger role in explaining men's sense of community, while formal sources of support are more important in explaining women's sense of community. Findings further suggest that African American workers, especially women, have a difficult time experiencing a sense of community at work. The authors thank the employees of Fel-Pro for their participation in this study and Melissa Roderick, Michael Sosin, and anonymous reviewers for their thoughtful comments. This research was funded by the Fel-Pro/Mecklenberger Foundation and the Lois and Samuel Silberman Fund.  相似文献   
993.
Investigated ethnicity and parental alcoholism as factors that might influence the stress vulnerability of adolescents. It extended an initial cross-sectional study of this same sample by adding two annual assessments which allowed for additional cross-sectional analyses and longitudinal tests. Hispanic and Caucasian adolescents (N=306 at Time 1) completed measures of their own life stress, family conflict, and alcohol use. Their parents reported on adolescents' internalizing and externalizing symptoms. Cross-sectional analyses at Time 2, and prospective analyses involving Time 1 and Time 2 measures were, for the most part, consistent with the original study's results. Caucasian adolescents and children of alcoholic parents appeared to be more vulnerable to stress than Hispanic adolescents and children of nonalcoholic parents. Family conflict was a partial explanation for this increased vulnerability. This research was supported by National Institute on Drug Abuse Grant DA05227 to Laurie Chassin (pricipal investigator) and Manuel Barrera, Jr. (coprincipal investigator). Susan Li was supported by an American Psychological Association Minority Fellowship Award. Portions of this research were presented at the conference, “Resiliency in Families: Racial and Ethnic Minority Families in America” that was held at the University of Wisconsin, May 31–June 2, 1994.  相似文献   
994.
There has been a paucity of research that has investigated whether skilled performers of a complex sports skill can readily change their technique. This study was designed to investigate whether swimmers skilled in the conventional breaststroke technique could adjust readily to the wave action technique. Nine masters swimmers with well established and stable movement patterns for the conventional technique were coached in the wave action breaststroke technique. The swimmers were videotaped from the side during maximum speed trials of the conventional breaststroke technique before coaching and the wave action technique after ten 45-minute coaching sessions. The amplitude and phase of the waveforms comprising the vertical displacements of the body parts were determined by Fourier analysis. In response to the coaching, the amplitude of the fundamental frequency of the vertex of the head, shoulders, hips, and knees increased significantly (p < 0.01). The percentage of power contained in the fundamental frequency of the shoulder and hip vertical displacements also increased significantly (p < 0.01). All subjects changed the relative phase of the fundamental frequencies of the vertex, shoulder, and hip vertical displacements. It was concluded that in this complex skill, major changes to the low frequency waveforms comprising the motion were achieved readily.  相似文献   
995.
ABSTRACT Biomedical experimentation on animals is justified, researchers say, because of its enormous benefits to human beings. Sure, animals suffer and die, but that is morally insignificant since the benefits of research incalculably outweigh the evils. Although this utilitarian claim appears straightforward and relatively uncontroversial, it is neither straightforward nor uncontroversial. This defence of animal experimentation is likely to succeed only by rejecting three widely held moral presumptions. We identify these assumptions and explain their relevance to the justification of animal experimentation. We argue that, even if non-human animals have considerably less moral worth than humans, experimentation is justified only if the benefits are overwhelming. By building on and expanding on arguments offered in earlier papers, we show that researchers cannot substantiate their claims on behalf of animal research. We conclude that there is currently no acceptable utilitarian defence of animal experimentation. Moreover, it is unlikely that there could be one. Since most apologists of animal experimentation rely on utilitarian justifications of their practice, it appears that biomedical experimentation on animals is not morally justified .  相似文献   
996.
997.
To examine whether guilt would inhibit immoral behavior, subjects were differentiated on their feelings of anticipatory (AG) and posttransgressional (PTG) guilt and subsequently placed in an anagram task shown to induce a high level of cheating. Results indicated that neither pre- nor post-test AG was related to cheating behavior, and test-retest administration indicated that the AG scale was unreliable. The PTG scale, however, was found to be a temporally reliable measure of guilt. In order to assess the relative contributions of pre-test posttransgressional guilt, the ability to persist, and gender to cheating behavior, a saturated multiple regression model of centered predictor effects and interaction terms was constructed. Results revealed a significant gender × persistence interaction. The cheating behavior of males was not significantly influenced by the ability to persist. On the other hand, females who exhibited a strong ability to persist rarely cheated, while those who were unable to persist cheated a great deal. Finally, subjects who felt the most posttransgressional guilt cheated more frequently. These findings provide additional evidence that guilt may be positively related to cheating behavior.  相似文献   
998.
Although there is considerable empirical support for the existence of social stereotypes about different types of mothers, the content of those stereotypes is less clear. The purpose of this study was to identify the content of stereotypes related to different types of mothers. Stereotyped attributes of married mothers, stepmothers, divorced mothers, and never married mothers were generated by several samples and combined into one list. A subsequent sample was asked to indicate the percentage of each type of mother possessing each characteristic. The content of mother stereotypes was examined, and the results discussed in light of effects on social interactions, the self-image of women, and future attempts to assess family-related stereotypes.  相似文献   
999.
1000.
Memory of size and orientation of objects was tested in explicit and implicit memory tests. Explicit memory was tested by object recognition and by recognition of the congruency of the changed sensory features. Implicit memory was tested by size assessment (Exps. 1 and 2), orientation judgement (Exps. 4 and 5), picture-fragment naming (Exp. 6), and classification (Exps. 3 and 7). Memory of sensory features was investigated by the comparison of performances of test-congruent with test-incongruent stimuli (i.e., same size or orientation vs. different size or orientation). The main result was a dissociation between these two tasks pertaining to the influence of sensory congruency on performance. However, it was in opposition to the usual relationship between the type of test and the perceptual similarity from study to test. In this study explicit, but not implicit, memory depended on sensory congruency. In the explicit tests performances were better when the stimuli were congruent than when they were incongruent. In the implicit test this variation had no influence. To get a repetition effect, it was important only that the object was repeated, and the size of this effect did not depend on sensory congruency. However, a change in another sensory feature — distortions of shape — strongly influenced the size of the repetition effect in the implicit test. Neither transfer-appropriate processing nor a system approach can easily explain this pattern of results. A multi-level, multi-token model is proposed to account for the different effects of sensory features in explicit and implicit memory.  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