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   3295篇
  免费   361篇
  国内免费   2篇
  2024年   5篇
  2023年   74篇
  2022年   39篇
  2021年   51篇
  2020年   172篇
  2019年   115篇
  2018年   118篇
  2017年   211篇
  2016年   217篇
  2015年   152篇
  2014年   163篇
  2013年   546篇
  2012年   161篇
  2011年   133篇
  2010年   121篇
  2009年   123篇
  2008年   128篇
  2007年   120篇
  2006年   133篇
  2005年   75篇
  2004年   72篇
  2003年   63篇
  2002年   44篇
  2001年   32篇
  2000年   21篇
  1999年   28篇
  1998年   14篇
  1997年   14篇
  1996年   50篇
  1995年   42篇
  1994年   32篇
  1993年   35篇
  1992年   42篇
  1991年   38篇
  1990年   41篇
  1989年   23篇
  1988年   21篇
  1987年   17篇
  1986年   23篇
  1985年   7篇
  1984年   6篇
  1983年   6篇
  1982年   8篇
  1981年   14篇
  1980年   15篇
  1979年   17篇
  1978年   20篇
  1977年   23篇
  1976年   5篇
  1975年   5篇
排序方式: 共有3658条查询结果,搜索用时 15 毫秒
811.
Many studies have dealt with the relative impact of parents and peers on adolescent substance use. However, only a few studies have explored the role of adolescents themselves in social relationships. Homogeneity in behavioral patterns within friendships can also be generated by selective association. Acknowledgment of selection processes might shed new light on the debate on the influences of parents and friends. This paper examines the impact of parental and best friends' smoking and drinking on adolescents' use, using data (N= 1,063) from a 3-wave, 5-year longitudinal study. The results show that friends' smoking did not affect adolescent smoking over time. Only in early adolescence did friends' drinking exert an influence on subjects' alcohol use. On the other hand, parental use had a small but significant impact on their offspring. Furthermore, support was found for processes of selective association.  相似文献   
812.
A total of 130 female undergraduates performed a counter-conditioning choice-task. This task presented two response alternatives and subjects were instructed to earn the maximum number of points. Responses to button 1 were normally followed by an immediate reward (an average gain of 7.5 points). Responses to button 2 were always followed by a punishment (an average loss of 20 points), but caused the next-but-one press on button 1 to give an average gain of 115 points. Thus, subjects were required to learn and maintain this counter-conditioning association. Four groups of subjects were formed according to the scores on the Sensitivity to Punishment and Sensitivity to Reward scales (which are measures of individual differences of Gray's anxiety and impulsivity personality dimensions, respectively). A 69.2% of subjects learned and maintained the counter-conditioning association. As predicted, personality results confirmed that subjects with lower scores on the Sensitivity to Punishment scale learned the counter-conditioning association better and faster when compared with high scorers. Results are consistent with Gray's Behavioral Inhibition System (BIS) model of anxiety which holds that individual differences in anxiety may relate to the ability to associate aversive stimuli with a future reward. Assuming that anxiety depends on BIS functioning, our results show that high trait anxious subjects, if compared with low anxious ones, would have a lower ability for associating an aversive event with a later appetitive one. This learning process would serve non-anxious subjects to reduce the aversiveness of cues of punishment and to cope better with stressful situations.  相似文献   
813.
Authors describe a multicultural training model for family therapists and psychologists at a traditionally conservative Afrikaans speaking university in South Africa. Black psychologists are now receiving high priority in a masters degree program that leads to professional registration licensure because of the needs of the population. The authors emphasize the importance of being able to think multidimensionally and creating a context in which students can do the same in such contexts.  相似文献   
814.
In this paper I use the concept of forbidden knowledge to explore questions about putting limits on science. Science has generally been understood to seek and produce objective truth, and this understanding of science has grounded its claim to freedom of inquiry. What happens to decision making about science when this claim to objective, disinterested truth is rejected? There are two changes that must be made to update the idea of forbidden knowledge for modern science. The first is to shift from presuming that decisions to constrain or even forbid knowledge can be made from a position of omniscience (perfect knowledge) to recognizing that such decisions made by human beings are made from a position of limited or partial knowledge. The second is to reject the idea that knowledge is objective and disinterested and accept that knowledge (even scientific knowledge) is interested. In particular, choices about what knowledge gets created are normative, value choices. When these two changes are made to the idea of forbidden knowledge, questions about limiting or forbidding lines of inquiry are shown to distract attention from the more important matters of who makes and how decisions are made about what knowledge is produced. Much more attention should be focused on choosing directions in science, and as this is done, the matter of whether constraints should be placed on science will fall into place.  相似文献   
815.
A questionnaire probing the distribution of authorship credit was given to postdoctoral associates (“postdocs”) in order to determine their awareness of the professional society’s ethical statement on authorship, the extent of communication with their supervisors about authorship criteria, and the appropriateness of authorship assignments on submitted papers. Results indicate a low awareness of the professional society’s ethical statement and that little communication takes place between postdocs and supervisors about authorship criteria. A substantial amount of authorship credit given to supervisors and other workers is perceived by the postdocs to violate the professional society’s ethical statement.  相似文献   
816.
817.
The present study addresses the question of what kind of information children use when orientating in new environments, if given proximal and distal landmarks, and how spatial memory develops in the investigated age groups. Ten 5-year-old, ten 7-year-old and ten 10-year-old children were presented with the ‘Kiel Locomotor Maze’, containing features of the Radial Arm Maze and the Morris Water Maze, in order to assess spatial memory and orientation. Children had to learn to approach baited locations only. Task difficulty was equated with respect to the children's age. Training was given until the children reached criterion. During testing, the maze configuration and response requirements were systematically altered, including response rotation, cue rotation, cue deletion and response rotation with cue deletion in order to assess the spatial strategies used by the children. During training and testing, working-memory errors (WM), reference-memory errors (RM) and working-reference memory errors (WR) were recorded. As expected, no difference between age groups appeared during training, thus confirming comparable task difficulty across age groups. During testing, age groups differed significantly with regard to the orientation strategy used. The 5-year-olds were bound to a cue strategy, orientating towards local, proximal cues. The 10-year-olds mastered all tasks, thus displaying a place strategy, being able to use distal cues for orientation, and were even able to do so after being rotated 180°. The 7-year-olds proved to be at an age of transition: five of them were bound to a cue strategy, five children were able to adopt a place strategy. The differences in the orientation strategies used by children of different age groups was reflected by the sum of errors they made, also by RM. WM were found to be rare, especially in older children. We conclude that preschoolers use a cue strategy, that the development of place strategies occurs during primary school age and seems to be complete by the age of 10 years.  相似文献   
818.
The semantical structures called T×W frames were introduced in (Thomason, 1984) for the Ockhamist temporal-modal language, O, which consists of the usual propositional language augmented with the Priorean operators P and F and with a possibility operator . However, these structures are also suitable for interpreting an extended language, SO, containing a further possibility operator s which expresses synchronism among possibly incompatible histories and which can thus be thought of as a cross-history simultaneity operator. In the present paper we provide an infinite set of axioms in SO, which is shown to be strongly complete forT ×W-validity. Von Kutschera (1997) contains a finite axiomatization of T×W-validity which however makes use of the Gabbay Irreflexivity Rule (Gabbay, 1981). In order to avoid using this rule, the proof presented here develops a new technique to deal with reflexive maximal consistent sets in Henkin-style constructions.  相似文献   
819.
The effects of gender, age and school grade on several career exploration dimensions measured by the Career Exploration Survey were investigated. Subjects were high school students facing an imminent career decision. Regression analyses indicated that sex and grade-level were the most significant and prevailing individual characteristics related to the adolescents' career exploration behaviours, reactions and beliefs. Implications for career exploration interventions are discussed.  相似文献   
820.
Perceptual and response bias in estimating the proportion of the two segments of prebisected lines were disambiguated in a group of 121 patients suffering from left neglect by means of two variants of the Milner Landmark task (Milner et al., 1993). The first variant, LANDMARK-V, required a verbal response; the second variant, LANDMARK-M, required manual pointing. The paper reports and discusses the results obtained on each task and their correlations, as well as the relationships between either kind of bias and the intrahemispheric location of the lesion. It is argued that besides their usefulness as a diagnostic tool the proposed variants of the Milner Landmark task provide results that are worth further investigation in their own right.  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