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   69016篇
  免费   2972篇
  国内免费   35篇
  2020年   854篇
  2019年   973篇
  2018年   1409篇
  2017年   1430篇
  2016年   1489篇
  2015年   1081篇
  2014年   1284篇
  2013年   5900篇
  2012年   2367篇
  2011年   2446篇
  2010年   1469篇
  2009年   1458篇
  2008年   2046篇
  2007年   1992篇
  2006年   1819篇
  2005年   1512篇
  2004年   1564篇
  2003年   1488篇
  2002年   1424篇
  2001年   2385篇
  2000年   2225篇
  1999年   1659篇
  1998年   764篇
  1997年   666篇
  1996年   718篇
  1995年   655篇
  1994年   641篇
  1993年   633篇
  1992年   1361篇
  1991年   1248篇
  1990年   1248篇
  1989年   1200篇
  1988年   1161篇
  1987年   1077篇
  1986年   1090篇
  1985年   1133篇
  1984年   921篇
  1983年   796篇
  1979年   914篇
  1978年   694篇
  1975年   761篇
  1974年   883篇
  1973年   868篇
  1972年   765篇
  1971年   694篇
  1970年   604篇
  1969年   645篇
  1968年   776篇
  1967年   665篇
  1966年   655篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
281.
Effects of alternative reinforcement sources: A reevaluation   总被引:3,自引:3,他引:0       下载免费PDF全文
The effects of two alternative sources of food delivery on the key-peck responding of pigeons were examined. Pecking was maintained by a variable-interval 3-min schedule. In the presence of this schedule in different conditions, either a variable-time 3-min schedule delivering food independently of responding or an equivalent schedule that required a minimum 2-s pause between a key peck and food delivery (a differential-reinforcement-of-other-behavior schedule) was added. The differential-reinforcement-of-other-behavior schedule reduced response rates more than did the variable-time schedule in most instances. The delay between a key peck and the next reinforcer consistently was longer under the differential-reinforcement-of-other-behavior schedule than under the variable-time schedule. Response rates and median delay between responses and reinforcers were negatively correlated. These results contradict earlier conclusions about the behavioral effects of alternative reinforcement. They suggest that an interpretation in terms of response–reinforcer contiguity is consistent with the data.  相似文献   
282.
Pigeons can discriminate locations presented in pictures   总被引:3,自引:3,他引:0       下载免费PDF全文
The present experiments were designed to teach pigeons to discriminate two locations represented by color photographs. Two sets of photographs were taken at two distinctive locations on a university campus. These sets represented several standpoints at each location. For the true-discrimination group, pictures from the two locations were differentially associated with reward; for the pseudodiscrimination group, half of the views from each location were arbitrarily but consistently associated with reward. The former group acquired the discrimination much more rapidly. These birds also showed good transfer to new views from the standpoints used in training and to a new standpoint at each location not used in training. In a second experiment, another group of pigeons could terminate any training trial by pecking an “advance” key. Three of 4 subjects used this option to reduce the duration of trials in which pictures from the negative location were presented. These data suggest that pigeons can integrate views shown in pictures into a “concept” of a location. The method used here may be the experimental analogue of a common, natural process by which animals learn to identify locations.  相似文献   
283.
In a study of air traffic controllers, religious differences are found in the way Type A behavior is associated with several health status indicators. Associations between the Jenkins Activity Survey (JAS) and physical illness incidence, health-promotive behavior, diastolic and systolic blood pressure, subjective distress and impulse control problems, and alcohol consumption are examined by religious attendance, religious affiliation, and change in affiliation. Findings confirm that Type A does not vary significantly by religion. However, there are several significant findings between Type A and various health indicators. Type A is associated with illness incidence, overall and more strongly in several religion, subgroups. Type A and alcohol consumption are related positively in Protestants and converts, and negatively in churchgoing Catholics. Type A is related to impulse control problems in churchgoing Protestants and to subjective distress in churchgoing Catholics. Finally, in individuals with weak or no religious ties, Type A is associated with lower blood pressure. This last finding suggests that in some people (for example, the irreligious or unchurched), the coronary-prone behavior pattern may have cardiovascular effects which are salutary in at least one respect.The authors wish to thank Dr. Kyriakos S. Markides and Laura A. Ray for their assistance with this study. Address requests for reprints to Dr. Levin at the Institute of Gerontology, 300 North Ingalls, Ann Arbor, MI 48109.  相似文献   
284.
285.
286.
Past research in referential communication has indicated normally developing children show developmental progression in ability to communicate a specific referent to a listener. In one paradigm subjects were given lists of word-pairs in which one member of each pair was designated as the referent. It was shown that communicating about referents found in word-pairs associated in some way was more difficult than communicating about referents in dissimilar word-pairs. The present study extended this methodology to learning-disabled children. Learning-disabled, language-learning-disabled, and normally achieving children were asked to communicate about 30 pictured referents on three different tasks. On Tasks 1 and 2 each subject was asked to give a clue for the referent that would distinguish it from the other picture. Stimuli for Task 1 were 30 pairs of pictures that were related in some way and the stimuli for Task 2 were 30 pairs of unrelated pictures. Task 3 required the subjects to evaluate the adequacy of the examiner's clues for Task 1 stimuli. The disabled subjects were matched to the normally achieving subjects on the basis of receptive vocabulary age. Few differences were noted among the groups' performances on these referential communication tasks. Implications include the importance of vocabulary and concept development to referential communication.  相似文献   
287.
This report examines two methodologic concerns pertaining to use of the cloze procedure in studying the predictability of schizophrenic speech, scoring criteria and raters' education (at or below college level). We find that two strategies for scoring the predictions of raters, one requiring the exact word, the other permitting a reasonable synonym, do not appear to differ in distinguishing groups of patients. The accuracy of raters' guessing is, however, correlated with raters' education: the more educated the rater, the more accurate the guessing. Thought-disordered schizophrenic speech is significantly less predictable than that of nonthought-disordered schizophrenics and normal controls when scored by less educated raters. These differences diminish when more highly educated raters are used. We conclude that raters' education can influence the sensitivity of cloze analysis.  相似文献   
288.
32 children 5 to 6 yr. old, 32 9 to 11 yr. old, and 32 adults linked musical fragments to emotions in a similar manner, older subjects being more accurate. Some emotions were more difficult than others; anger and fear were often confused. Older subjects gave better justifications for their choices.  相似文献   
289.
We hypothesized that in the decodification of connotative aspects of visual chromatic stimuli the periphery of the body plays an important role. In particular we hypothesized that the decodification process of so called "warm" and "cold" colours is related to a real modification of the temperature of the body which is the basis of the "subjective feeling" and of the attribution of the "emotional meaning" to the stimulus. So we have measured the temperature of the body of 36 female psychology students while they were looking at a luminous screen through spectacles in which filters (coloured lenses) of different colours were placed. Analysis indicated that during the perception of so called "warm" colours a statistically significant increase in the temperature of the body appeared. We observed an enhancement of temperature on the left side of the body during the perception with red and yellow filters and a small increase in temperature on the right side of the body with orange and yellow filters. In the discussion of the results we considered also the role of the cerebral dominance in decodification process of the connotative components of stimuli.  相似文献   
290.
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