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   54739篇
  免费   2127篇
  国内免费   35篇
  2020年   563篇
  2019年   666篇
  2018年   875篇
  2017年   896篇
  2016年   1029篇
  2015年   705篇
  2014年   834篇
  2013年   4148篇
  2012年   1575篇
  2011年   1613篇
  2010年   967篇
  2009年   1047篇
  2008年   1423篇
  2007年   1368篇
  2006年   1221篇
  2005年   1106篇
  2004年   1069篇
  2003年   1004篇
  2002年   1047篇
  2001年   1634篇
  2000年   1612篇
  1999年   1178篇
  1998年   553篇
  1997年   531篇
  1992年   1039篇
  1991年   988篇
  1990年   958篇
  1989年   940篇
  1988年   902篇
  1987年   860篇
  1986年   886篇
  1985年   967篇
  1984年   804篇
  1983年   742篇
  1982年   553篇
  1981年   564篇
  1979年   864篇
  1978年   630篇
  1977年   567篇
  1976年   576篇
  1975年   743篇
  1974年   857篇
  1973年   913篇
  1972年   773篇
  1971年   729篇
  1970年   653篇
  1969年   698篇
  1968年   857篇
  1967年   789篇
  1966年   752篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
922.
Pretrial publicity and a temporal interval between the news and trial were explored for their effects upon the jury's deliberation process and verdict. Publicity (neutral, negative) and trial timing (immediate, delayed) were manipulated in a 2 × 2 design. Twenty 12-person simulated juries were exposed either to neutral or negative publicity and viewed a videotaped criminal trial immediately following news exposure or after a one-week delay between news and trial. Dichotomous pre-and postdeliberation verdicts, probability of guilt scales, trial recall, ratings of companion jurors, perceptions of attorneys, assessments of the news article, and recall of news facts were measured. Deliberations were tape recorded and content analyzed. Juries exposed to neutral and negative publicity did not significantly differ on conviction rate, deliberation length, or on quality of deliberations. Prejudicial news elicited counter remarks about the threatening nature of the publicity to the defendant's right to a fair trial. Individual juror data revealed that while the news manipulation did not significantly affect predeliberation verdicts or attention to trial events, negative news lowered jurors' probability estimates of guilt and facilitated their recall of news facts. A discriminant analysis predicting jury verdict indicated a lack of support for prior research showing damaging effects from prejudicial pretrial publicity. Findings are explored for methodological implications and for usefulness of theoretical notions of reactance, and "sleeper effects".  相似文献   
923.
Two studies were conducted to investigate the effects of perceived control in two men's prisons, one housing 181 inmates and the other housing 623 inmates. In both prisons, inmates' perceived control over the environment was found to be significantly related to their ratings of their living accommodations, experienced stress, and physical symptoms, even when type of cell was held constant.  相似文献   
924.
925.
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   
926.
Pigeon's observational learning of successive visual discrimination was studied using within-subject comparisons of data from three experimental conditions. Two pairs of discriminative stimuli were used; each bird was exposed to two of the three experimental conditions, with different pairs of stimuli used in a given bird's two conditions. In one condition, observers were exposed to visual discriminative stimuli only. In a second condition, subjects were exposed to a randomly alternating sequence of two stimuli where the one that would subsequently be used as S+ was paired with the operation of the grain magazine. In a third experimental condition, subjects were exposed to the performance of a conspecific in the operant discrimination procedure. After exposures to conspecific performances, there was facilitation of discriminative learning, relative to that which followed exposures to stimulus and reinforcement sequences or exposures to stimulus sequences alone. Exposure to stimulus and food-delivery sequences enhanced performance relative to exposure to stimulus sequences alone. The differential effects of these three types of exposure were not attributable to order effects or to task difficulty; rather, they clearly were due to the type of exposure.  相似文献   
927.
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   
928.
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   
929.
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   
930.
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   
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