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   21499篇
  免费   76篇
  2021年   18篇
  2020年   17篇
  2019年   24篇
  2018年   3501篇
  2017年   2834篇
  2016年   2263篇
  2015年   211篇
  2014年   103篇
  2013年   168篇
  2012年   621篇
  2011年   2424篇
  2010年   2536篇
  2009年   1493篇
  2008年   1722篇
  2007年   2206篇
  2006年   73篇
  2005年   256篇
  2004年   200篇
  2003年   141篇
  2002年   100篇
  2001年   49篇
  2000年   68篇
  1999年   29篇
  1998年   40篇
  1997年   30篇
  1996年   14篇
  1995年   10篇
  1994年   18篇
  1993年   17篇
  1992年   21篇
  1991年   14篇
  1990年   22篇
  1989年   14篇
  1988年   12篇
  1987年   23篇
  1986年   18篇
  1985年   19篇
  1984年   9篇
  1983年   20篇
  1982年   14篇
  1980年   13篇
  1978年   9篇
  1977年   8篇
  1976年   15篇
  1975年   11篇
  1974年   14篇
  1973年   8篇
  1972年   10篇
  1971年   15篇
  1968年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
A critical application of Ruddick's model of maternal thinking is the best way to grapple with the ethical dilemmas posed by sex-selective abortion which I view as a "moral mistake." Chief among these is the need to be sensitive to local cultural practices in countries where sex-selective abortion is prevalent, while simultaneously developing consistent international standards to deal with the dangers posed by the use of sex-selective abortion to eliminate female fetuses.  相似文献   
62.
This paper discusses family work with older adults by exploring some of the related literature published since Herr and Weakland's work in 1979, and compares psychoeducational and systems-based approaches to work with later life families. Issues of bias and omissions in the existing literature, and the definition of family therapy with this client group are raised. Areas for future research are indicated.  相似文献   
63.
As the principle of timing or opportunity,kairos serves both as a powerful theme within technological discourse and as an analytical concept that explains some of the suasory force by which such discourse maintains itself and its position in our culture. This essay makes a case for a rhetoric of technology that is distinct from the rhetoric of science and illustrates the value of the classical vocabulary for understanding contemporary rhetoric. This case is made by examining images and models of technological change that underlie and justify the thematizations ofkairos that appear in so much technological discourse and by exploring the phenomenon of technological forecasting, in which the characterization and construction of moments in the present are crucial to the projection of the future. One example of forecasting is examined in detail: the Japanese Fifth Generation computer project, which illustrates the twin themes of opportunity and threat.  相似文献   
64.
65.
This study assessed the effect of presenting single versus multiple exemplars of basic-level categories on 24-month-olds' long-term memory for categorical information. Sixty-four infants were tested in a paired-comparison recognition memory paradigm immediately and one week after familiarization with basic-level categories. Infants were randomly assigned to one of two familiarization conditions and one of two test conditions. In one familiarization condition (Varied Exemplar), they briefly viewed four different exemplars of each of 16 basic-level categories. In the other familiarization condition (Single Exemplar), they viewed only one instance of each category on four different trials. Test trials consisted of either an exemplar seen during familiarization (Familiar-Exemplar Test) or novel intracategory exemplar (Unfamiliar-Exemplar Test) paired with a stimulus from a novel category. Both immediately following familiarization and one week later, infants looked longer at test stimuli from the novel category irrespective of familiarization or test condition.  相似文献   
66.
Instrumental treadle press and nonreinforced key peck responses were monitored during discrimination training and generalization testing in pigeons on positive and negative reinforcement schedules. In Experiment 1, six pigeons pressed a treadle for food on a multiple variable-interval extinction schedule. In Experiment 2, three pigeons pressed a treadle to avoid shock on a multiple free-operant avoidance extinction schedule. Different color keylights signaled S+ and S- components. Some positive behavioral contrast occurred during discrimination training, but the effect was small. Pecking occurred to the S+ keylight in Experiment 1 but not in Experiment 2. On stimulus generalization tests, all subjects displayed a positive peak shift when pressing the treadle for food or to avoid shock. However, peak shift was not found for nonreinforced "autopecks" on the stimulus key, although an area shift was observed in Experiment 1. This is the first demonstration of peak shift for pigeons pressing treadles and the only reliable demonstration of peak shift when negative reinforcement maintained responding. These results, in combination with previous demonstrations of peak shift for rats pressing levers and pigeons pecking keys, indicate that peak shift is a general by-product of operant discrimination learning, since it occurs across a variety of the organisms, responses, and reinforcers.  相似文献   
67.
This study examines the relative importance of three behavioral dimensions to reading and mathematics achievement of elementary school children. Previous research on the dimensions which characterize the school behavior of children has shown that these dimensions can be understood as reflecting (a) an adaptation or learning problems dimension, (b) an interpersonal or a social problem dimension, and (c) an intrapersonal or personal adjustment dimension. Scores for each dimension were derived from a cluster analysis of the Pupil Behavior Rating Scale. Based on results of the cluster analysis, subjects were assigned to 12 behavioral typology groups. Analysis of variance showed that behavior typologies were related to both reading and mathematics achievement test scores. Post hoc contrasts revealed that levels of reading achievement are associated primarily with behaviors defined by attributes of the adaptation dimension, and that differences in measures of interpersonal and interpersonal dimensions do not contribute appreciably to group differences in reading and mathematics achievement.  相似文献   
68.
According to previous research, young children do not understand displaced aggression. The present study examines the early phases of the understanding of the causes of moderately and extremely displaced aggression. Preschool and kindergarten children (3 to 5 years of age) viewed eight videotaped episodes of displaced aggression. Their comprehension of this aggression was assessed by means of open ended questions and forced choice picture selections. By age 5 most children had some understanding of displaced aggression, but this understanding was not complete. The early understanding revealed in the present study may be due to the use of short, simple realistic videotaped episodes appropriate for the limited processing abilities of young children. Extreme displacement was not more difficult to understand than moderate displacement.  相似文献   
69.
Long-term retention of operant footkicking acquired in the mobile conjugate reinforcement paradigm was assessed as a function of the distribution of training time. In the first study, 3-month-old infants were trained for either one 18-min session or for two 9-min or three 6-min sessions separated by 24-hr intervals. All infants exhibited retention during a test administered immediately after training, but only those trained in a single session continued to perform the conditioned response during cued-recall tests 7 or 14 days later. Infants trained in three sessions showed no evidence of remembering the contingency even after a week. A warm-up decrement, seen in the day-to-day performance of infants in the distributed conditions, was eliminated in the second study by the interpolation of a nonreinforcement period at the outset of daily sessions. This procedure also enhanced long-term retention such that infants trained in three 6-min session now remembered the contingency for 14 days and did not differ from infants who had received a single 18-min session. Whether distributed training facilitates or impairs long-term retention appears to depend on the opportunity for infants to acquire a sufficient number (or kind) of effective retrieval cues during original learning.  相似文献   
70.
The present experiments were designed to study the conditions under which failure would enhance or inhibit subsequent task performance. Based on the theory of Wortman and Brehm (1975), it was expected that small amounts of failure would produce reactance (manifested by improved performance at a subsequent task), whereas large amounts would lead to learned helplessness (i.e., impaired later performance). It was further expected that individual differences in self-esteem and private self-consciousness would serve as moderator variables for the above effects. In Experiment 1, subjects were exposed to either a small amount of failure or no failure before working on an anagrams task. As predicted, subjects high in self-consciousness, who have shown greater reactance arousal in attitude change studies, performed better on the anagrams task than subjects low in self-consciousness in the small-failure condition, but not in the no-failure condition. Further analyses revealed that this Self-Consciousness X Small Failure interaction was attributable to the performance data of the low, but not the high self-esteem subjects. Experiment 2 was designed to replicate and extend these results. Subjects were pretreated with either a small amount of failure, an extended amount of failure, or no failure before working on the anagrams task. A significant Self-Esteem X Helplessness Training interaction emerged. Relative to the no-failure condition, in which the two self-esteem groups did not differ, low self-esteem participants (low SEs) performed marginally better than did high self-esteem individuals (high SEs) in the small-failure condition but significantly worse than high SEs in the extended-failure condition. The effect of private self-consciousness was considerably weaker in this study, possibly because the sample included few low SEs (who are especially influenced by self-focused attention) who were also relatively low in self-consciousness. Questionnaire data from Experiment 2 were consistent with the notion that enhanced performance reflected reactance, whereas impaired performance signified helplessness.  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