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   65314篇
  免费   2643篇
  国内免费   20篇
  67977篇
  2020年   665篇
  2019年   835篇
  2018年   1145篇
  2017年   1148篇
  2016年   1254篇
  2015年   923篇
  2014年   1081篇
  2013年   4919篇
  2012年   2016篇
  2011年   2184篇
  2010年   1359篇
  2009年   1332篇
  2008年   1934篇
  2007年   1946篇
  2006年   1783篇
  2005年   1594篇
  2004年   1481篇
  2003年   1387篇
  2002年   1504篇
  2001年   2071篇
  2000年   2015篇
  1999年   1568篇
  1998年   765篇
  1997年   707篇
  1996年   687篇
  1993年   623篇
  1992年   1313篇
  1991年   1210篇
  1990年   1183篇
  1989年   1065篇
  1988年   1055篇
  1987年   1010篇
  1986年   1089篇
  1985年   1107篇
  1984年   932篇
  1983年   855篇
  1982年   616篇
  1981年   625篇
  1979年   979篇
  1978年   725篇
  1975年   809篇
  1974年   869篇
  1973年   942篇
  1972年   788篇
  1971年   750篇
  1970年   669篇
  1969年   693篇
  1968年   893篇
  1967年   796篇
  1966年   691篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
Superimposition of response-independent reinforcement   总被引:6,自引:6,他引:0       下载免费PDF全文
Studies that have superimposed response-independent reinforcement (or reinforcers scheduled by contingencies placed on the absence of responding) upon conventional response-dependent schedules are reviewed. In general, providing alternative sources of reinforcement reduced response rates below the levels observed when alternative reinforcement was absent. However, response-rate elevation was sometimes found, particularly when rates of superimposed response-independent reinforcement were low. Superimposition of schedules providing reinforcers contingent on the absence of responding usually produced more severe response-rate decrements than superimposition of response-independent reinforcement. A variant of Herrnstein's equation, which assumes that some of the alternative reinforcers function as if they were delivered by baseline response-dependent source of reinforcement, is in qualitative agreement with the overall body of results obtained, and can predict both increases and decreases in response rate as resulting from superimposed reinforcers.  相似文献   
902.
Seven albino rats were exposed to a multiple schedule of reinforcement in which the two components (fixed interval and extinction) alternated such that a presentation of the extinction component followed each fixed-interval reinforcement. In baseline sessions, the duration of the extinction component was constant and always one-third of the fixed-interval value. Probe sessions contained a probe segment in which the duration of the extinction component was increased; the response rate in fixed-interval components during the probe segment was compared with the response rate in the segments preceding and following the probe. The effect of increasing the duration of the extinction component was studied under three values of fixed interval: 30 s, 120 s, and 18 s, in three successive conditions. Response rate within fixed intervals was a direct function of duration of the extinction component. Pausing at the beginning of the fixed interval decreased as extinction duration increased. These effects were larger and more consistent for the shorter fixed-interval values (18 s and 30 s). These results indicate a functional relation between relative component duration and responding. For the component providing more frequent reinforcement, this could be stated as an inverse relationship between relative component duration and response rate. This relation is similar to findings regarding the ratio of trial and intertrial duration in Pavlovian conditioning procedures, and suggests that behavioral contrast may be related to Pavlovian contingencies underlying the multiple schedule.  相似文献   
903.
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   
904.
Belief systems and attitudes toward the death penalty and other punishments   总被引:1,自引:0,他引:1  
This study focused on the relationship of belief systems as a configural construct and conservatism-liberalism to attitudes toward the death penalty and other punishments for offenses of varying severity Extrapersonalists, the most concretely functioning of the four conceptual or belief systems posited by Harvey, Hunt, and Schroder (1961), were most in favor of the death penalty They also endorsed the most severe punishment for a variety of crimes, to a particularly greater extent than did representatives of either of the two more abstractly functioning systems The belief dimensions of Openness, Evaluativeness, and Complexity, as well as the frequency of church attendance, correlated more highly and consistently with attitudes toward punishment than did either Conservatism-Liberalism or gender Both of the latter variables failed to correlate with a number of the outcome variables and related at only low levels to the others The greater predictive power of a configural conception of personality or belief systems over a unidimensional conception seems to have been demonstrated Configural concepts may additionally be generally superior to multidimensional concepts treated linearly  相似文献   
905.
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   
906.
The Social Relations Model: An integrative method for personality research   总被引:1,自引:0,他引:1  
As outlined by Snyder and Ickes (1985), the study of personality can be undertaken using one of three research approaches dispositional, situational, and interactive We show how the Social Relations Model provides an integrative method to estimate simultaneously dispositional, situational, and interactive effects Reviewed are component approaches to the study of personality The Social Relations Model is shown to be a component model (a special case of generalizability theory) applied in a social interaction context In the model, dispositional, situational, and interactive effects are termed actor, partner, and relationship effects, respectively The Social Relations Model can be used to answer a number of important issues in personality research The model can be used to assess reliability, measure the validity of self-ratings, and validate self-report inventories The model requires special designs in winch each person interacts with multiple partners Empirical examples are presented in which social anxiety, sex role inventories, and self-disclosure are studied  相似文献   
907.
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   
908.
Recent studies have provided strong support for the convergent validity of the General Behavior Inventory (GBI), a case identification inventory for chronic subsyndromal affective disorders (cyclothymia and dysthymia). Fewer data are available, however, on the ability of the GBI to distinguish chronic subsyndromal affective disorders from other forms of psychopathology. In order to address this issue, outpatients with cyclothymia (n = 9), dysthymia (n = 26), nonchronic major depression (n = 16), and nonaffective psychiatric disorders (n = 30) were compared on the GBI. Diagnoses were derived blind to GBI scores using structured diagnostic interviews and DSM-III criteria. The inventory significantly discriminated cyclothymes and dysthymes from patients with nonchronic major depressions and nonaffective disorders. Using the cutoff score that maximized GBI-diagnosis concordance, the inventory correctly classified 88% of the sample. All of the cyclothymes, 92% of the dysthymes, 87% of the patients with nonaffective psychiatric disorders, and 75% of the nonchronic major depressives were correctly classified by the inventory. These data provide strong support for the discriminant validity of the GBI.  相似文献   
909.
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   
910.
On the basis of a self-validation perspective, it was predicted that distortions in consensus estimates would vary as a function of attribute type (opinions versus abilities), relevance of the attribute, and individual differences in self-esteem and depression. Students rated themselves on seven opinion and ability dimensions using 5-point Likert scales. Then they estimated the percentage of the other students who held each opinion/ability position, and rank ordered the opinions/abilities for personal relevance. Absolute and directional accuracy scores were computed (comparing estimated percentages with actual percentages in the sample), as well as false consensus (FCE) scores (comparing estimates of subjects holding and not holding a particular position). Subjects overestimated consensus for their opinions and low abilities, but underestimated consensus for their high abilities. Although subjects exhibited a larger FCE on opinions than abilities, there was a reliable FCE for both attributes. Relevance affected the magnitude of these biases. Higher opinion relevance was associated with increased accuracy, lower FCE scores, and smaller overestimates. Higher ability relevance was associated with decreased accuracy, greater overestimation on low abilities, and greater underestimation on high abilities. Finally, low self-esteem and depressed subjects overestimated consensus on opinions and underestimated consensus on abilities less than high self-esteem and nondepressed subjects.  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