全文获取类型
收费全文 | 74456篇 |
免费 | 2803篇 |
国内免费 | 20篇 |
出版年
2020年 | 661篇 |
2019年 | 858篇 |
2018年 | 2302篇 |
2017年 | 2174篇 |
2016年 | 2003篇 |
2015年 | 952篇 |
2014年 | 1090篇 |
2013年 | 4984篇 |
2012年 | 2211篇 |
2011年 | 3022篇 |
2010年 | 2227篇 |
2009年 | 1797篇 |
2008年 | 2538篇 |
2007年 | 2728篇 |
2006年 | 1758篇 |
2005年 | 1605篇 |
2004年 | 1476篇 |
2003年 | 1362篇 |
2002年 | 1463篇 |
2001年 | 2244篇 |
2000年 | 2204篇 |
1999年 | 1649篇 |
1998年 | 765篇 |
1997年 | 666篇 |
1996年 | 683篇 |
1993年 | 615篇 |
1992年 | 1376篇 |
1991年 | 1291篇 |
1990年 | 1280篇 |
1989年 | 1162篇 |
1988年 | 1145篇 |
1987年 | 1098篇 |
1986年 | 1159篇 |
1985年 | 1168篇 |
1984年 | 995篇 |
1983年 | 884篇 |
1982年 | 647篇 |
1981年 | 630篇 |
1979年 | 1040篇 |
1978年 | 738篇 |
1975年 | 860篇 |
1974年 | 934篇 |
1973年 | 1044篇 |
1972年 | 868篇 |
1971年 | 828篇 |
1970年 | 740篇 |
1969年 | 766篇 |
1968年 | 976篇 |
1967年 | 880篇 |
1966年 | 759篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
321.
U W Huck R D Lisk E J Parente 《Journal of comparative psychology (Washington, D.C. : 1983)》1988,102(4):388-391
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
322.
K J Arbour D M Wilkie 《Journal of comparative psychology (Washington, D.C. : 1983)》1988,102(2):177-181
When given a choice between two mashes of equal caloric density but differing flavors, rats (Rattus norvegicus) show a robust preference for the flavor previously associated with a higher calorie food. This finding suggests that rats may identify food quality by sensory cues such as taste. Our initial attempt to show this effect in the golden Syrian hamster (Mesocricetus auratus) failed, apparently because of this species's tendency to store both high- and low-calorie mashes in their cheek pouches during conditioning trials. Initially we attempted to circumvent this seeming morphological constraint on learning by presenting low- and high-calorie mashes on alternate days. This procedure too failed to produce evidence of flavor-caloric learning, although this procedure produced robust learning in another rodent, the Mongolian gerbil (Meriones unguiculatus). Another method of preventing cheek pouching--concurrently presenting low- and high-calorie liquid diets--was more successful; then, hamsters showed clear evidence of flavor-caloric learning. Thus, although flavor-caloric learning is demonstrable in species of rodent besides the rat, the circumstances under which it occurs vary. 相似文献
323.
Perceptual organization of acoustic stimuli by budgerigars (Melopsittacus undulatus): III. Contact calls 总被引:1,自引:0,他引:1
S D Brown R J Dooling K O'Grady 《Journal of comparative psychology (Washington, D.C. : 1983)》1988,102(3):236-247
We trained budgerigars by operant conditioning to discriminate among a set of contact calls in a same-different task and analyzed response latencies from this task by using multidimensional-scaling (MDS) and cluster-analysis procedures. Humans listened to the same calls and indicated the similarity between pairs of calls by a direct rating procedure. An MDS program (sindscal) was used to arrange these complex acoustic stimuli in multidimensional space reflecting perceptual organization. Multiple regression techniques were used to identify the acoustic characteristics of contact calls that were correlated with the perceptual dimensions obtained from MDS. A number of spectral characteristics (e.g., peak frequency, rate of frequency modulation, and concentration of spectral energy) emerged as important for both budgerigars and humans, but the relative salience of these cues differed for the two species. Additional tests with two groups of budgerigars--cagemates and noncagemates--showed that experience with calls can change the salience of various acoustic characteristics used for perceptual organization and individual recognition. 相似文献
324.
325.
Frank N. Dempster 《Applied cognitive psychology》1988,2(2):97-113
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
326.
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
327.
JOSEPH A. JOHNSTON KEITH L. BUESCHER MARY J. HEPPNER 《Journal of counseling and development : JCD》1988,67(1):39-41
Computerized career information and guidance systems, although now commonplace, have received little psychometric scrutiny. The authors argue for examining these systems in the same way in which paper and pencil instruments are assessed. Consideration is also given to issues related to programming, technical-service problems, and staffing. 相似文献
328.
Marianne Kastrup MD Inge Kemp Genefke MD Inge Lunde MD JØrgen Ortmann MD 《Contemporary Family Therapy》1988,10(4):280-287
This paper describes approaches taken at the International Rehabilitation and Research Centre in Copenhagen to helping torture victims and their families cope with the exposure to and aftermath of torture. 相似文献
329.
Linda N. Bly 《Contemporary Family Therapy》1988,10(4):243-255
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
330.