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   83364篇
  免费   3405篇
  国内免费   38篇
  86807篇
  2020年   837篇
  2019年   1094篇
  2018年   1473篇
  2017年   1479篇
  2016年   1613篇
  2015年   1148篇
  2014年   1366篇
  2013年   6291篇
  2012年   2536篇
  2011年   2683篇
  2010年   1645篇
  2009年   1690篇
  2008年   2325篇
  2007年   2366篇
  2006年   2151篇
  2005年   1909篇
  2004年   1787篇
  2003年   1678篇
  2002年   1781篇
  2001年   2682篇
  2000年   2652篇
  1999年   1995篇
  1998年   940篇
  1997年   852篇
  1996年   839篇
  1995年   797篇
  1993年   772篇
  1992年   1668篇
  1991年   1533篇
  1990年   1521篇
  1989年   1407篇
  1988年   1395篇
  1987年   1314篇
  1986年   1377篇
  1985年   1435篇
  1984年   1204篇
  1983年   1099篇
  1982年   810篇
  1979年   1281篇
  1978年   923篇
  1975年   1029篇
  1974年   1155篇
  1973年   1261篇
  1972年   1082篇
  1971年   988篇
  1970年   887篇
  1969年   926篇
  1968年   1176篇
  1967年   1061篇
  1966年   926篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Testicular self-examination (TSE) can lead to early diagnosis and treatment of testicular cancer, the third leading cause of death in young men. We evaluated the effectiveness of a brief and specific checklist for teaching TSE skills. Ten men were videotaped while performing testicular self-examinations before and after training. The TSE training resulted in large and significant increases in the number of TSE steps completed and duration of the TSE. Two urological validation measures supported the improvements observed in the mens' self-examinations. Subjects reported continued performance of TSE during a follow-up telephone interview. This pilot study indicates that a brief and specific checklist is an effective strategy for teaching early cancer detection skills.  相似文献   
942.
Video games vary in terms of the emotional states they elicit from players. These differences in emotional reactions, in turn, help account for differential preferences of individual games. The three independent dimensions of pleasure-displeasure, arousal-nonarousal, and dominance-submissiveness were used to assess emotional impacts of individual games. In addition, a preference measure was constructed to evaluate attraction toward, versus avoidance of, specific games. In Study One, a group of subjects provided data on emotional responses to 22 common arcade video games and a different group rated their preferences for the same games. The emotional impact of video games was highly unpleasant, moderately arousing, and moderately dominance-inducing; thus, the predominant emotional response to these games was aggression, anger, or hostility. I n Study Two, subjects visiting a video game arcade were recruited and assigned to play two games each and to report their reactions to each game immediately after playing the game. Results showed that greater feelings of pleasure, and separately of arousal, while playing video games resulted in higher preferences for the games and that greater dominance (significant only for males) also led to higher preferences. It may be beneficial, therefore, to experiment with more arousing and more dominance-inducing game designs which are not necessarily unpleasant or which definitely yield high pleasure.  相似文献   
943.
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   
944.
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   
945.
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   
946.
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   
947.
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   
948.
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   
949.
The mainstream view of love is that it is a state that arises from people mutually reinforcing each other or providing benefits to each other Yet careful quantitative analyses of imaginative thought patterns of people in love or in a state of affiliative arousal reveal themes of dialogue, commitment, and harmony rather than of mutual benefits It is suggested that asking people about love leads them to give causal explanations for the state which psychologists have elaborated into the theory that love is a response to having one's needs met Imaginative experiences characteristic of the state of being in love on the other hand may be different because they are primarily right brain mediated and do not share in the causal, instrumental type of reasoning characteristic of left brain conscious thinking Such conceivably right brain mediated experiences in TATs are more closely associated than presumably left brain mediated self-reports are with such physiological measures as evoked scalp potentials, neurohormone concentrations, and immune functions A vew of love that takes both self-report (left brain) and fantasy (right brain) measures into account does a better job of predicting affiliative behavior than does a view that relies solely on one or the other of the two types of measures  相似文献   
950.
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   
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