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   28769篇
  免费   857篇
  国内免费   14篇
  2020年   265篇
  2019年   257篇
  2018年   502篇
  2017年   540篇
  2016年   624篇
  2015年   388篇
  2014年   409篇
  2013年   1958篇
  2012年   982篇
  2011年   1005篇
  2010年   489篇
  2009年   480篇
  2008年   681篇
  2007年   682篇
  2006年   603篇
  2005年   1774篇
  2004年   1120篇
  2003年   864篇
  2002年   629篇
  2001年   789篇
  2000年   800篇
  1999年   605篇
  1998年   273篇
  1997年   235篇
  1992年   480篇
  1991年   452篇
  1990年   516篇
  1989年   466篇
  1988年   434篇
  1987年   450篇
  1986年   453篇
  1985年   460篇
  1984年   368篇
  1983年   326篇
  1982年   244篇
  1981年   221篇
  1979年   431篇
  1978年   290篇
  1977年   263篇
  1976年   240篇
  1975年   373篇
  1974年   416篇
  1973年   387篇
  1972年   358篇
  1971年   320篇
  1970年   292篇
  1969年   343篇
  1968年   383篇
  1967年   345篇
  1966年   348篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The role of perceived efficacy, parent support, and community involvement in the self-esteem and ethnic identity of 68 African-American male youth were investigated in this research. The results provided support for the distinctiveness of ethnic identity and self-esteem. A sense of mastery was positively associated with both self-esteem and ethnic identity. Parent support was associated with self-esteem, while community involvement and an appreciation of African-American heritage were positively related to ethnic identity. Implications for future research and the evaluation of prevention and support programs for youth are discussed.  相似文献   
992.
This paper presents a behavioral model which proposes that operants are organized and regulated into systems of responding. Multi-operant theory proposes that operants are organized into response systems that interact to adapt behavior to the complexities of the environment. The operant is the interaction between behavior and the environment which includes the conditions under which responses may occur, the class of behavior that is likely to be effective in producing outcomes, and the antecedent conditions that define the context of behavior. A central feature of this theory is that operants within a repertoire are organized into regulated systems of responding. The mechanisms of regulation are themselves operants that are learned and controlled by processes that are the same as those that govern more overt behavior. Operants stand in relationship to each other in coordinated response systems with some operants directly affecting and organizing the performance of other operants. An important implication of the systemic nature of behavioral repertoires is that bringing some aspect of a behavior class under control of new variables may demonstrate a spread throughout the entire operant system depending on past histories linking the classes.deceased  相似文献   
993.
994.
This article presents a theoretical argument to explain the way in which unemployed people react to and cope with threats to their identities that derive from perceptions ofstigma and low self-worth. It is argued here that strategies used by unemployed people to cope with such threats are influenced by whether the individuals categorize themselves as “unemployed” or adopt some other categorization (e.g., housewife, retired coal-miner). It is also proposed that the concept of self-categorization can be framed within Folkman and Lazarus’s (1980, 1985) coping model of distress in order to provide a more general framework for understanding these issues. The study reviews literature about stigma and coping with threatened identities with reference to these integrated frameworks, and concludes with a general model for predicting the way in which unemployed people self-categorize and cope with stigma and low self-esteem. This takes into account the role played by situational and individual factors, and suggests that individuals recategorize themselves in order to cope better during different phases of their unemployment.  相似文献   
995.
A compelling impression of movement, which is perceptually indistinguishable from a real displacement, can be elicited by patterns containing no spatially displaced elements. An apparent oscillation, w-movement, was generated by a stationary pattern containing a large number of horizontal pairs of spatially adjacent dots modulated in brightness. The observer’s task was to adjust the perceived amplitude of the w-motion to match the amplitude of a real oscillation. All of the data can be accounted for by a simple rule: If the relative change in the luminance,W = αL/L, between two adjacent stationary dots is kept constant, the distance over which these dots appeared to travel in space comprises a fixed fraction of the total distance by which they are separated. The apparent amplitude of the w-motion increases strictly in proportion with luminance contrast, provided that the contrast is represented in the motion-encoding system by a rapidly saturating compressive Weibull transformation. These findings can be explained in terms of bilocal motion encoders comparing two luminance modulations occurring at two different locations.  相似文献   
996.
997.
Enhancing possible selves in Mexican American students   总被引:3,自引:0,他引:3  
This project assessed the modifiability of possible selves in young Mexican American children. Three intervention conditions were compared in a pre- and posttest design: child-only intervention, parent and child intervention, and a no-intervention control. Following eight intervention sessions, children in the two intervention groups showed significant gains in understanding the characteristics associated with becoming a good student and in recognizing the value of education in bringing about future occupational goals. Children in the intervention conditions also reported greater interest in becoming a physician, judge, or pilot — occupations they had directly experienced during training. The parent intervention phase contributed little to augmenting the positive results attributable to the child intervention component.This research was conducted under the auspices of NIH Grant HD-24003. We wish to thank Maritza Robles and the staff of the Bilingual program of the South Bend, IN, Corporation for their support.  相似文献   
998.
999.
Two experiments are reported addressing the preparation and initiation of movements with equal or unequal timing properties for both hands. Temporal coordination was examined in two movement tasks: one in which both hands performed the movements simultaneously (simultaneous aiming task) and one in which only one alternative of two possible movements was executed (choice aiming task). For each task a different group of subjects was used. Besides the timing relationships between both movements, the effects of preparation interval (1, 3, and 5 s), the average velocity (7, 14, 17.5, and 70 cm/s), the presence of advance information about the required velocity of the movement(s), and practice were investigated. Based on the common- and the specific-timing notions, distinct hypotheses were tested as to the effects of the variables on the temporal coordination as revealed by reaction time. A main result was that the effects of timing differences between the hands was task specific. For the choice task the data are in agreement with the common-timing notion of coordination, i. e., only one timing demand at a time can be prepared, whereas in the simultaneous task evidence was obtained for the specific-timing notion, i. e., independent preparation and initiation of different timing properties for the hands. However, it is argued that the results of the choice task probably do not reflect a general inability to prepare movements of different timing requirements for both hands, but is related to a task-specific strategy of selective preparation.  相似文献   
1000.
Hall  Judith A.  Halberstadt  Amy G. 《Sex roles》1994,31(3-4):149-165
Sex Roles - Women's superiority in decoding nonverbal cues of emotion has often been discussed as an adaptation to low status. To examine the relation of status to nonverbal sensitivity,...  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