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   56929篇
  免费   2127篇
  国内免费   27篇
  2020年   610篇
  2019年   722篇
  2018年   1004篇
  2017年   1116篇
  2016年   1121篇
  2015年   762篇
  2014年   958篇
  2013年   4369篇
  2012年   1779篇
  2011年   1827篇
  2010年   1158篇
  2009年   1097篇
  2008年   1597篇
  2007年   1617篇
  2006年   1442篇
  2005年   1281篇
  2004年   1224篇
  2003年   1155篇
  2002年   1188篇
  2001年   1745篇
  2000年   1729篇
  1999年   1332篇
  1998年   603篇
  1997年   566篇
  1993年   520篇
  1992年   1111篇
  1991年   988篇
  1990年   1063篇
  1989年   960篇
  1988年   975篇
  1987年   928篇
  1986年   946篇
  1985年   915篇
  1984年   795篇
  1983年   741篇
  1982年   566篇
  1981年   524篇
  1979年   895篇
  1978年   646篇
  1977年   573篇
  1975年   751篇
  1974年   827篇
  1973年   860篇
  1972年   673篇
  1971年   639篇
  1970年   574篇
  1969年   677篇
  1968年   784篇
  1967年   711篇
  1966年   647篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Children aged 1.5 to 8 years were required to touch accurately an illuminated target lamp located on a vertical board. Movements were made when visual information was complete (target lit for 3 s, room illuminated; partial (target lit for 3 s, room dark, and reduced (target lit for 0.7 s, room dark). Dependent variables were response accuracy, reaction time, and movement time. Accuracy decreased with decreasing availability of visual information and improved with age under all conditions. Reaction times were shorter in the dark (Conditions 2 and 3) than in the light; they decreased with age up to age 5 and did not continue to decrease thereafter. Movement time did not change with age under Conditions 1 and 3 but tended to increase with age under Condition 2. Slower movements were more accurate at all ages, provided visual feedback could be utilized. Increased reliance on the strategy "slower movements yield higher accuracy" was held to account for developmental changes under Condition 2, whereas in Conditions 1 and 3 improvement in the efficiency of motor preprogramming was implicated.  相似文献   
952.
953.
954.
We investigated the control judgments of Type A and B actors and observers after five tasks in which actual response-outcome contingency and success were varied systematically. Results indicated that, overall, actors provided higher control judgments than did observers, and both actual contingency and success influenced judged control. Type A and B actors did not differ in their self-perceptions of control but observers judged the Type A actors to have exerted more control than the Type B actors, primarily on positive contingency tasks. These findings suggest that Type As, because of their more active, dynamic style, may be credited by observers with more control or competence than is warranted. By contrast, the more relaxed style of the Type B may lead to lower than warranted evaluations of control or competence. Lastly, Type As were found to learn the contingencies better than Type Bs with important implications for the actual exercise of control.  相似文献   
955.
Predicting adult temperament from minor physical anomalies   总被引:1,自引:0,他引:1  
It is known that in children, individual differences in temperament are linked to rates of minor physical anomalies (MPAs). These anomalies are a standard set of 17 nonobvious but measurable characteristics of the face, hands, and feet. We explored the relation between MPAs and temperament in adults. An intact sample of 88 undergraduates completed a battery of personality tests and lifestyle questions, and then were examined for MPAs. The index of MPAs for each subject was simply the total count out of 17. The results showed a pattern of correlates parallel to that found in children. Among male subjects, correlations with MPAs were significant for the Physical Activity and Clumsiness factors of the lifestyle inventory as well as for measures of emotionality, extraversion, masculinity, femininity, and Type A personality. The MPA index was also predictive of a behavioral index of temperament in male subjects. No correlations were significant among female subjects.  相似文献   
956.
We examined the effects of behavioral procedures to modify the food choices of preschoolers during a snack period at school (training setting) and at home (generalization setting). In the first experiment, we evaluated the usefulness of nutrition training and a generalization programming strategy of cueing to improve healthy snacking; in the second experiment we investigated the effect of nutrition training alone. In addition, three cases are presented that illustrate individualized procedures to facilitate generalization of healthy snacking to home. Results indicated that children's healthy snack choices increased in the preschool training setting, that generalization to home was achieved only when procedures to program it were implemented, and that the best results were found when the generalization procedures were tailored to the individual child.  相似文献   
957.
Questionnaires concerning attitudes toward use of microcomputers at home, in school, and at video arcades were administered to 879 high school students. Direct observations of adolescent proxemics and sex differences, and of various parameters of video games in 18 video arcades were made. A thorough and representative content analysis of sex bias of microcomputer software advertising brochures was carried out. Results supported previous findings of overrepresentation of masculine culture in the adolescent world of microcomputers, particularly regarding video games. Various types of computer-related activity were not related to socioeconomic class of the parents or to academic grades except for use of home microcomputers, which was mildly positively related to socioeconomic class (r = .124, p less than .001). Nearly half the activity in the arcades was strictly solitary. None of the arcade video games allowed for cooperative play. Most allowed only for sequential competition (86%) or simultaneous competition (7%); as many as 7% did not provide a display of the scores for a second player.  相似文献   
958.
Squirrel monkeys were trained to respond under a multiple fixed-interval, fixed-interval schedule in which the first response after 5 min terminated a visual stimulus in the presence of which electric shocks could occur. During one component of the schedule, correlated with one color of stimulus lights, every 30th response also produced electric shock; responding was suppressed during this component to approximately 10 to 12% of that occurring in the alternate component in which responding was not punished. In contrast to previous research, morphine (0.03 to 1.0 mg/kg) increased punished responding. Unpunished responding, however, was either not affected or decreased at doses of morphine that increased punished responding. Increases in rate of punished responding also occurred when the single-schedule punishment condition was studied alone in these animals. Subsequent experimentation, which systematically analyzed the development of the rate-enhancing effects of morphine on punished responding, involved the study of drug effects in additional monkeys trained initially under a single-schedule punishment condition. The effects of morphine on punished responding were studied before, after, and then during exposure to the multiple schedule that included a component in which responding was not punished. Increases in response rate with morphine did not occur until it was administered during exposure to the multiple schedule that included a component in which responding was not punished. As with the other monkeys, once the rate increases in punished responding occurred under the multiple schedule, these effects of morphine persisted, even when the multiple schedule was removed.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
959.
Theories of observing differ in predicting whether or not a signal for absence of reinforcement (S−) is capable of reinforcing observing responses. Experiments in which S− was first removed from and then restored to the procedure have yielded mixed results. The present experiments suggest that failure to control for the direct effect of presenting S− may have been responsible. Pigeons and operant procedures were used. Experiment 1 showed that presentations of S−, even when not contingent on observing, can raise the rate of an observing response that was reinforced only by presentations of a signal (S+) that accompanied a schedule of food delivery. Experiment 2 showed that this effect resulted from bursts of responding that followed offsets of S−. Experiment 3 showed that, when the presence of S− was held constant, lower rates occurred when S− was dependent on, rather than independent of, observing. These results support theories that characterize S− as incapable of reinforcing observing responses.  相似文献   
960.
In previous studies subjects who have learned a positioning response with kinesthetic feedback tended to make greater errors when visual feedback was provided during later trials. These subjects have always performed with both kinesthetic and visual feedback available. This study determined whether subjects with only visual feedback would produce errors similar to those who received kinesthetic plus visual feedback. Blindfolded subjects learned to move a handle to a criterion location with knowledge of results following each trial. Subjects then were assigned to one of three experimental groups, with only kinesthetic feedback, with kinesthetic plus visual feedback, or with only visual feedback. Subjects had 9 trials without knowledge of results in these feedback conditions. When visual feedback was available, subjects tended to make longer response errors. This finding replicates previous studies. Also, the similarity of performances from the conditions with visual feedback indicated the dominance of visual information in the condition with kinesthetic plus visual feedback.  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