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   57514篇
  免费   2391篇
  国内免费   21篇
  2020年   698篇
  2019年   815篇
  2018年   1167篇
  2017年   1184篇
  2016年   1225篇
  2015年   894篇
  2014年   1072篇
  2013年   4981篇
  2012年   1994篇
  2011年   1997篇
  2010年   1192篇
  2009年   1226篇
  2008年   1725篇
  2007年   1690篇
  2006年   1566篇
  2005年   1282篇
  2004年   1330篇
  2003年   1269篇
  2002年   1214篇
  2001年   1954篇
  2000年   1826篇
  1999年   1386篇
  1998年   649篇
  1997年   559篇
  1996年   644篇
  1995年   576篇
  1994年   569篇
  1993年   555篇
  1992年   1125篇
  1991年   1037篇
  1990年   1019篇
  1989年   976篇
  1988年   956篇
  1987年   890篇
  1986年   878篇
  1985年   924篇
  1984年   752篇
  1983年   649篇
  1982年   514篇
  1979年   785篇
  1978年   581篇
  1976年   497篇
  1975年   623篇
  1974年   695篇
  1973年   715篇
  1972年   610篇
  1971年   567篇
  1968年   615篇
  1967年   535篇
  1966年   509篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The possible role of "effort" in the accuracy of pigeons' performance on a delayed matching-to-sample procedure was investigated by examining the effects of response requirements that accompanied a trial-initiating stimulus and that accompanied a sample stimulus. In the first experiment, the effect of varying the size of a fixed-ratio requirement for responses during an initiating stimulus was compared to that of varying a similar requirement for responses during the sample stimulus. Accuracy increased reliably with increases in the ratio scheduled during the sample stimulus, but was not significantly affected by increases in the ratio scheduled on the key during the initiating stimulus. In another phase of Experiment 1, sample duration was held constant while the ratio requirement was varied during the initiating stimulus. Again, accuracy of matching to sample was not significantly affected by the size of the ratio scheduled during the initiating stimulus. Experiment 2 provided a systematic replication of these results in another group of pigeons and included a more detailed analysis of responding. These results support the view that increases in sample-response requirement facilitate accuracy of delayed matching by increasing the durations of exposure to the sample stimuli, and do not support a role of effort in the sample-response effect. In Experiment 3, the facilitative effect of responses on the sample but not of those on the initiating stimulus was replicated using a simultaneous matching-to-sample procedure. This finding provides further evidence against an interpretation of response-requirement effects that appeals to effort; the finding also suggests that sample exposure might affect initial discrimination of the sample rather than remembering the sample.  相似文献   
992.
Three experiments describe the effects of manipulating the frequency of response-reinforcer contiguity in a recycling conjunctive schedule. The schedule arranged that a reinforcer was delivered after 30 s provided at least one response had occurred; otherwise the next cycle started immediately. In Experiment 1, this schedule produced the typical pause–respond–pause pattern, with most responses at mid-interval; and, when a limited number of contiguities between responses and food delivery were added, the pattern became more like the monotonic scallop seen on fixed-interval schedules. In Experiment 2, the schedule was initially presented with an additional contingency that allowed contiguity on every trial. Fixed-interval-like behavior occurred and tended to persist as contiguities were gradually eliminated. In Experiment 3, the recycling conjunctive schedule alternated with a condition in which a large number of contiguities occurred. The pause–respond–pause pattern and fixed-interval-like performance occurred with few or many contiguities, respectively. The results of all three experiments illustrate how contiguity interacts with a small number of other variables to determine performance on interval schedules and illuminate previous findings with fixed-interval and fixed-time schedules.  相似文献   
993.
Thirty-one college undergraduates learned to touch abstract stimuli on a computer screen in arbitrarily designated “correct” sequential orders. Four sets of seven stimuli were used; the stimuli were arrayed horizontally on the screen in random sequences. A correct response (i.e., touching first the stimulus designated as first) resulted in that stimulus appearing near the top of the screen in its correct sequential position (left to right), and remaining there until the end of the trial. Incorrect responses (i.e., touching a stimulus out of sequence) terminated the trial. New trials displayed either the same sequence as the one on which an error had occurred (same-order correction procedure), or a new random sequence (new-order correction procedure). Whenever all responses occurred in the correct sequence, the next trial displayed a new random sequence. Each phase ended when five consecutive correct response sequences occurred. Initially, the same-order correction procedure increased control by the position as well as by the shape of the stimuli; also, it produced more errors, more total trials, more trials to mastery, and more individual patterns of reacquisition than were produced by the new-order procedure.  相似文献   
994.
In response to the article by Lamiell and Trierweiler (this issue), we examine the stated epistemological origins of idiothetic proposals for theory and research in personality We argue that the justification for those proposals as advanced by Lamiell and his colleagues is wholely insufficient in view of prior research on the consistency of behavior This assertion together with our identification of problems in scaling personality and personality consistencies lead us to conclude that the pursuit of the idiothetic method is both unwarranted and ineffectual  相似文献   
995.
This investigation examines the proposition that wives who describe their personality in ways that deviate from sex stereotypes will become less positive and more negative about their marriage from before to after they become mothers, particularly when the transition to parenthood is accompanied by an increase in the traditionalism of marital roles. Sixty-one couples were studied longitudinally from the last trimester of pregnancy through the third postpartum month. The wives completed the Personal Attributes Questionnaire (Spence & Helmreich, 1978), which measures the extent to which they ascribe personality attributes stereotyped as "masculine" (i.e., instrumental, agentic) and "feminine" (expressive, affectional) to themselves, and several questionnaires assessing the marital relationship at both times of measurement. Results revealed that the more division of labor changed toward traditionalism, the greater the decline in wives' evaluations of the positive aspects of marriage and that changes in wives' evaluations of both positive and negative aspects of marriage can be significantly predicted by the interaction of the wives' expressivity and changes toward increased traditionalism in division of labor. Additional analyses showed that wives who do not ascribe female sex-typed attributes to themselves (relative to those who see themselves in sex-stereotyped ways) are more apt to evaluate their marriage less favorably from before to after parenthood when roles shift toward greater traditionalism.  相似文献   
996.
The purpose of this paper is to examine the usefulness of factor analysis in developing and evaluating personality scales that measure limited domain constructs The approach advocated follows from several assumptions that a single scale ought to measure a single construct, that factor analysis ought to be applied routinely to new personality scales, and that the factors of a scale are important if it can be demonstrated that they are differentially related to other measures A detailed study of the Self-Monitoring Scale illustrates how factor analysis can help us to understand what a scale measures A second example uses the self-esteem literature to illustrate how factor analysis can clarify the proliferation of scales within a single content domain Both examples show how factor analysis can be used to identify important conceptual distinctions Confirmatory techniques are also introduced as a means for testing specific hypotheses It is concluded that factor analysis can make an important contribution to programmatic research in personality psychology  相似文献   
997.
This study assesses the relations between the ratings of clinicians and psychiatric inpatients on several anxiety and depression measures, as mediated by private self-consciousness. The overall concordance between clinicians' and patients' ratings is quite high, particularly on the depression measures. Levels of private self-consciousness do not appear to mediate concordance of structured behavior or symptom-based ratings of either anxiety or depression; however, there is limited support for levels of private self-consciousness mediating concordance between patients' global ratings of anxiety and clinicians' anxiety ratings.  相似文献   
998.
The relation of Type A behavior to IQ, academic achievement, and several clinically relevant dimensions of behavior in children was assessed in 873 fourth, fifth, and sixth graders by means of the Matthews Youth Test for Health (MYTH), the Cognitive Abilities Test (CAT), the Iowa Tests of Basic Skills (ITED), and the teachers' form of the Missouri Children's Behavior Checklist (MCBC-T). The MYTH and its competitiveness and impatience-aggression subscales were found to be differentially related to academic achievement and to account for a small but significant portion of the variance in achievement not accounted for by IQ. The subscales of the MYTH were found to be highly correlated with several clinically familiar dimensions of children's behavior. The significance of these findings for the construct validity of the MYTH is discussed.  相似文献   
999.
1000.
The study of adolescent sexual development has typically focused on the incidence and age of onset of particular behaviors. Recent developments in the analysis of covariance structures permit more powerful simultaneous tests of the determinants of adolescent sexual behavior. These new methods allow the assessment and evaluation of the interrelatedness between unobserved, latent constructs. Data were obtained from 183 males and 193 females ranging in age from 12 to 18 years old, selected from three birth cohorts using a stratified random sample. Eight latent constructs--Sexual and Dating Involvement, Self-Acceptance, Feminist Sex Role Attitudes, Deviant Social Network, Importance of Dating, Lack of Heterosexual Competence, Sexually Active Social Network, and Stressful Change Events--were hypothesized to explain the variance in 26 observed variables. Several causal models were tested that specified structural relationships among the latent constructs. A theoretically meaningful model was arrived at that linked the eight, error-free factors.  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