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   88799篇
  免费   3460篇
  国内免费   29篇
  92288篇
  2019年   1078篇
  2018年   1452篇
  2017年   1460篇
  2016年   1593篇
  2015年   1141篇
  2014年   1386篇
  2013年   7438篇
  2012年   2485篇
  2011年   2661篇
  2010年   1662篇
  2009年   1639篇
  2008年   2422篇
  2007年   2345篇
  2006年   2170篇
  2005年   1881篇
  2004年   1749篇
  2003年   1721篇
  2002年   1785篇
  2001年   2786篇
  2000年   2711篇
  1999年   2081篇
  1998年   995篇
  1997年   917篇
  1996年   1020篇
  1995年   944篇
  1993年   909篇
  1992年   1893篇
  1991年   1736篇
  1990年   1720篇
  1989年   1561篇
  1988年   1519篇
  1987年   1503篇
  1986年   1535篇
  1985年   1553篇
  1984年   1360篇
  1983年   1192篇
  1982年   899篇
  1981年   909篇
  1979年   1362篇
  1978年   1008篇
  1975年   1188篇
  1974年   1232篇
  1973年   1344篇
  1972年   1211篇
  1971年   1080篇
  1970年   989篇
  1969年   994篇
  1968年   1260篇
  1967年   1102篇
  1966年   1002篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
981.
The present experiment used hippocampal stimulation to determine the temporal gradient of consolidation of spatial working memory. Rats were trained to perform a spatial working memory task on a radial maze with 12 arms. Each rat went to the ends of 6 arms to obtain a food reward. After 8 h, the rat chose among all the arms to find the ones not previously chosen (and consequently still having food). During some test sessions, the hippocampus was stimulated electrically either at a current level just high enough to produce an electrophysiological seizure, or at a current level below this seizure threshold. Stimulation occurred at one of five intervals (0 to 8 h) following the completion of the first six choices. During other test sessions, the hippocampus was not stimulated. After seizure stimulation, the number of retroactive errors (returning to arms chosen prior to stimulation) increased at all delay intervals; the number of proactive errors (returning to arms chosen after stimulation) increased only with the delay of 8 h. Subthreshold stimulation had no influence on either type of error. These results indicate that normal hippocampal function is required for the maintenance of spatial information in working memory, and that the time course of consolidation of this information is significantly greater than that seen in other types of memory, or consolidation may not take place at all.  相似文献   
982.
Summary Soon after Wheatstone published his results obtained with the twelve earliest stereograms. Brewster disputed the result obtained with one of them. This stereogram consisted of a thick vertical line presented to one eye and a thin vertical and thick inclined line to the other. Wheatstone reported seeing depth with this figure but Brewster did not. We conducted three experiments to explore the possible reason for the disagreement. Experiment 1 indicated that the stereogram produces a variety of perceptions including the depth as reported by Wheatstone and the rivalry as reported by Brewster. Experiment 2 showed that Brewster's procedure of keeping the eyes fixed while viewing the stereogram reduces the proportion of subjects reporting depth. In Experiment 3, the top half and the bottom half of the stereogram were presented in different trials. The top of the stereogram that contains no conflicting cues produced reliable depth, but the bottom that does, did not. It is concluded that the difference in the procedures they used and the nature of the stimulus were responsible for the conflicting results.  相似文献   
983.
Some effects of color on naming and recognition of objects   总被引:1,自引:0,他引:1  
In this article, we investigated the role of color in the recognition and naming of everyday objects. In the first experiment we found that color pictures were named faster than black-and-white and that shape information did not facilitate color naming. Experiment 2 was carried out to determine at which stage of object processing the color facilitation occurred. We found that color had no effect on object recognition but did facilitate object naming, even when color was redundant for discrimination. This did not apply to naming abstract shapes. Experiment 3 replicated the findings of Experiment 2 using different objects and colors. The results showed that color could facilitate but not inhibit object naming and did not affect object recognition.  相似文献   
984.
Do alcoholic Korsakoff's syndrome patients acquire affective reactions?   总被引:1,自引:0,他引:1  
In this study we report two experiments that investigate the acquisition of affective reactions. In Experiment 1, unfamiliar melodies were played to Korsakoff's syndrome patients and alcoholic and nonalcoholic control subjects who were matched with them according to age and education. Following a retention interval of 5 min, subjects received a preference test on old and new melodies. Korsakoff's syndrome patients showed the same increase in preference for old melodies as a consequence of prior exposures as control subjects did, but their recognition of melodies was significantly impaired in comparison with controls. In Experiment 2, the same subjects saw photographs of two men. Fictional biographical information depicted one as a "good guy" and the other as a "bad guy." After a retention interval of approximately 20 days, Korsakoffs recalled virtually none of the biographical information; however, 78% preferred the good guy, and impression ratings were less favorable for the bad guy. Korsakoff patients developed preferences and impressions even though they did not have voluntary access to the information on which the preferences were based. However, their impression ratings were less extreme than those of controls. The pattern of results of the two studies is discussed in terms of Johnson's (1983) MEM model of memory.  相似文献   
985.
The true receptive field of more than 90% of neurons in the middle temporal visual area (MT) extends well beyond the classical receptive field (crf), as mapped with conventional bar or spot stimuli, and includes a surrounding region that is 50 to 100 times the area of the crf. These extensive surrounds are demonstrated by simultaneously stimulating the crf and the surround with moving stimuli. The surrounds commonly have directional and velocity-selective influences that are antagonistic to the response from the crf. The crfs of MT neurons are organized in a topographic representation of the visual field. Thus MT neurons are embedded in an orderly visuotopic array, but are capable of integrating local stimulus conditions within a global context. The extensive surrounds of MT neurons may be involved in figure-ground discrimination, preattentive vision, perceptual constancies, and depth perception through motion cues.  相似文献   
986.
Stephen  Timothy D.  Harrison  Teresa M. 《Sex roles》1985,12(1-2):195-206
The present study was designed to investigate the relationship experience of males and females who do not conform to sex-typical orientations to intimacy. One hundred sixty-three couples' and 88 nondating singles' (total N=414) responses to the Relationship World Index—Version 2 (RWI-2) were analyzed via discriminant analysis to determine if subjects' sex could be predicted accurately upon the basis of their RWI-2 scores. One discriminant function was found which was significant by the Wilks' lambda test [x2(60)=140.57, p<.001]; the procedure correctly classified 76% of the respondents. Those who were classified correctly were considered sex-typical and the remaining 24% of the sample was considered non-sex-typical in their orientations to intimacy. Additional analyses using data from a 6-month longitudinal study located qualities which significantly distinguished sex-typical from non-sex-typical subjects and couples in which at least one member was non-sex-typical from couples in which both members were classified as sex-typical.  相似文献   
987.
The purpose of this study was to examine the attitudes of a general population toward female participation in sports and to replicate a previous study. The two areas investigated were (1) the perception of enhancement or detraction of femininity by girls' participation in athletics, and (2) whether different sports elicited different attitudes towards female participation in athletics. A town in Iowa was sampled. The results indicated that, in general, participation in sports neither detracted from nor enhanced femininity. Furthermore, most of the people wanted their daughters to play basketball, even though it neither detracted from nor enhanced femininity. The data suggest that traditional, rigid sex-role stereotypes were transcended and the opportunity set was dominant.This study was partially funded by a grant from the University of Iowa Graduate School. Appreciation is expressed to Dr. Eldon Snyder for graciously sharing his instrument and recent work.  相似文献   
988.
A case-study of gay identity development is presented based on Kelly's personal construct theory. The subject is a married man in his early thirties. Repertory grid technique is used to investigate the subject's construing of his relationships with gay men, and Kelly's account of emotion in terms of constructs of transition is used in analysing the emotional dimensions of the subject's experience. Three dimensions of interpersonal construing emerged from the grid analysis: emotional impact, negative affect and friendship. Five aspects of the subject's emotional experience are discussed: aggression, threat, anxiety, hostility and guilt. Some implications of the study for counselling are outlined, its limitations noted, and possible avenues for further research identified. It is argued that the study serves to illustrate the value of Kelly's perspective in understanding the interpersonal and emotional dimensions of gay identity development.  相似文献   
989.
Young people's qualifications are strongly related to their occupational success. It is often assumed that this can be largely accounted for by employers' selection on the basis of attainment. A variety of attainment-related attitudes and behaviour among young people which may contribute to the relationship are examined. The findings suggest that qualifications subsume a variety of behavioural factors which have an important direct effect on young people's chances in the job market.  相似文献   
990.
The publication in 1973 of Student Counselling in Practice signalled a new phase in the development of both careers and counselling services in the tertiary sector. The emergence of the professional careers adviser in higher education is described alongside the key role of the Association of Graduate Careers Advisory Services. The gradual professionalisation of student counselling is shown to have taken a different form, as a result of the policies of the Association for Student Counselling with its insistence on role definition and the accreditation of practitioners. Developments in further education are briefly reviewed, and a final section considers the present situation and possible future trends.  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