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   54268篇
  免费   1369篇
  国内免费   12篇
  2019年   369篇
  2018年   3906篇
  2017年   3248篇
  2016年   2736篇
  2015年   617篇
  2014年   591篇
  2013年   2580篇
  2012年   1443篇
  2011年   3295篇
  2010年   3048篇
  2009年   2007篇
  2008年   2547篇
  2007年   2893篇
  2006年   796篇
  2005年   864篇
  2004年   815篇
  2003年   729篇
  2002年   708篇
  2001年   1052篇
  2000年   1035篇
  1999年   752篇
  1998年   371篇
  1997年   361篇
  1996年   361篇
  1992年   677篇
  1991年   642篇
  1990年   633篇
  1989年   597篇
  1988年   621篇
  1987年   557篇
  1986年   598篇
  1985年   580篇
  1984年   520篇
  1983年   430篇
  1982年   353篇
  1981年   348篇
  1979年   534篇
  1978年   410篇
  1977年   372篇
  1976年   368篇
  1975年   456篇
  1974年   567篇
  1973年   618篇
  1972年   483篇
  1971年   486篇
  1970年   439篇
  1969年   480篇
  1968年   596篇
  1967年   513篇
  1966年   537篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
182.
After 12-15 ejaculatory series, each consisting of several short intromissions (2- to 3-s vaginal penetration) and an ejaculation, male golden hamsters adopt an altered copulatory pattern consisting of long intromissions (5- to 25-s penetration with intravaginal thrusting). Receptivity declines and the tendency for the female to attack the male increases at about the time of this shift in copulatory pattern. Because the mean interintromission interval (III) between short intromissions is about 8 s compared to 100 s between long intromissions, it is possible that females detect this difference and adjust their mating accordingly. When the III between short intromissions from a rested male was experimentally increased to 100 s by use of a halter and lead device, the duration of lordosis was significantly less than that displayed by females paired with control males (8-s III) and virtually the same as that displayed by females paired with males that produced only long intromissions. This suggests that the female uses the temporal patterning of intravaginal stimulation as one criterion for terminating mating with a particular male.  相似文献   
183.
The sensitivity of naturalistic prose material to retroactive interference (RI) was investigated in three experiments, with due consideration given to the conditions known to produce RI in non-prose material. In experiment 1, unrelated, related, and nearly identical (parapharase) prose passage conditions yielded a pattern of results very similar to those obtained with non-prose material, with only the related condition associated with significant amounts of RI. Based upon these results and a few simple assumptions, a classificatory scheme was developed within which predictions were made regarding RI in related prose material. Several such predictions were tested and confirmed in Experiments 2 and 3. It was concluded that the many previous failures to detect RI in the retention of prose may be attributed to factors other than any inherent insensitivity of the material itself, and that RI may be just as predictable in prose as it is non-prose material.  相似文献   
184.
Previous research on the effect of lecture handouts on student learning indicates that students who are given skeletal handouts usually perform better in course examinations than students who take all their own notes. The present study investigates whether the amount of detail in the handout is a critical factor in this. A randomized groups experiment was conducted in the context of a course on dental surgery. Four lecture handout conditions (headings and full text; headings and key points; headings only; no supplementary materials) were compared on tests 2 days and 2 weeks after the lecture. The significant differences between conditions were: ‘headings only’ better than ‘headings and key points’ on the first test; ‘headings only’ better than ‘no supplementary materials’ on the second test; and ‘headings and full text’ better than ‘no supplementary materials’ on the second test. These results indicate that the amount of detail is a critical factor in handout effectiveness.  相似文献   
185.
The authors discuss the results of a study designed to assess nationally certified counselors' perceptions of the relevance of elements of the National Board for Certified Counselors examination to their work as counselors. Support for the validity and appropriateness of the examination in regard to perceived relevance and lack of differentiation on the basis of respondent characteristics were found.  相似文献   
186.
Bonaparte, G., Chapman, J., & Steinberg, J. (1987). Michigan: Two career guidance models. Vocational Education Journal, 62(6), 142–143. Greenwood, K. (1987). Counseling adults in career transition. Vocational Education Journal, 62(6), 44–46. Herr, E.L. (1987). Comprehensive career guidance and vocational education: Natural allies. Vocational Education Journal, 62(6), 30–33. Lambert, R. (1987). A guide to career information. Vocational Education Journal, 62(6), 34–36. Lester, J.N., & McCormac, M.E. (1987). The NOICC career guidance standards project. Vocational Education Journal, 62(6), 47–48. Otto, L.B. (1987). Parents: Key advisors. Vocational Education Journal, 62(6), 37–38.  相似文献   
187.
Study of child abusers reveals that many victimizers were once victims and that the behaviors underlying the perspectives of victims and victimizers are related. Three groups of abusing parents using directed self-help were studied at Parents Anonymous by participant observation methodology for two and-a-half years. Four of the 52 participating parents read and commented on a draft of the research. Their violence appeared to be an attempt to gain a sense of control or to deal with the frustration of not feeling in control. Suggestions are made for developing social services that enhance individuals' sense of control.Paper presented at the Groves Conference on Marriage and the Family, London, England, July, 1986.  相似文献   
188.
189.
190.
Age differences in short-term retroactive interference, unconfounded with age differences in rehearsal in the retention interval of the Brown-Peterson Task, were not found in a cross-sectional study of adults 18-32 and 64-78 years of age. Degree of retroactive interference was manipulated conjointly with distractor interval length (0-15 s). Individual memory span was assessed and used as the list length in order to achieve stimulus equivalence of memory loads across individuals and age groups. An attention-demanding matching task that adjusted itself in difficulty to the individual's attentional capacity was used as the distractor activity. Covert rehearsal during the retention interval was inferred using several measures, including a comparison of distractor task performance in the presence and in the absence of a memory load, and rehearsers were excluded from the primary analyses. We conclude that there is no interference proneness with increasing age in the present study.  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