全文获取类型
收费全文 | 29897篇 |
免费 | 1430篇 |
国内免费 | 20篇 |
出版年
2020年 | 452篇 |
2019年 | 439篇 |
2018年 | 616篇 |
2017年 | 649篇 |
2016年 | 704篇 |
2015年 | 519篇 |
2014年 | 662篇 |
2013年 | 2871篇 |
2012年 | 1093篇 |
2011年 | 1077篇 |
2010年 | 711篇 |
2009年 | 732篇 |
2008年 | 978篇 |
2007年 | 968篇 |
2006年 | 947篇 |
2005年 | 864篇 |
2004年 | 788篇 |
2003年 | 770篇 |
2002年 | 786篇 |
2001年 | 924篇 |
2000年 | 891篇 |
1999年 | 676篇 |
1998年 | 377篇 |
1997年 | 377篇 |
1996年 | 387篇 |
1995年 | 328篇 |
1994年 | 300篇 |
1993年 | 289篇 |
1992年 | 530篇 |
1991年 | 521篇 |
1990年 | 518篇 |
1989年 | 441篇 |
1988年 | 394篇 |
1987年 | 409篇 |
1986年 | 394篇 |
1985年 | 416篇 |
1984年 | 392篇 |
1983年 | 342篇 |
1982年 | 287篇 |
1981年 | 275篇 |
1980年 | 258篇 |
1979年 | 343篇 |
1978年 | 308篇 |
1977年 | 275篇 |
1976年 | 234篇 |
1975年 | 285篇 |
1974年 | 336篇 |
1973年 | 315篇 |
1972年 | 239篇 |
1968年 | 241篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
T D Crespi 《Adolescence》1988,23(92):805-811
The effectiveness of a time-out intervention for adolescent psychiatric patients, adjudicated (delinquent) youth, and behaviorally disordered youngsters was explored in this study. The research was conducted in three psychiatric hospitals for children and adolescents, a facility for adjudicated youth, and in a day-treatment program. Utilizing a comparative outcome model, 813 occurrences of time-out with 274 youth were investigated in order to assess levels of effectiveness. The results indicated that time-out had a significant impact, and the use of a child-care specialist as time-out monitor improves overall effectiveness. Important implications for practicing professionals and clinical researchers are noted. 相似文献
93.
94.
The influences of sex, age, and conversational, partner (mother vs. stranger) on eye contact during verbalizations were examined in a longitudinal study of 33 children at 2 and 4 years of age. A free-play sample was obtained of each child interacting with mother and with a male or female experimenter. The amount of eye contact in conjunction with verbalization was analyzed. Significant main effects were found for sex (females engaged in a higher percent of eye contact than males) and conversational partner (more eye contact while speaking exhibited to experimenter than to mother). There was an interaction between age and conversational partner, in that mother received more and experimenter relatively less percent of eye contact during verbalizations as children got older. Notably, there was no main effect for age. These results revealed sex differences at an age (2–2 1/2 years) and in a context (free-play setting) not previously studied, demonstrating the robustness of the effect. Further, age findings seem indicative of unique developmental trends for eye contact during verbalizations for the ages between 2 and 4 years.Mount Saint Vicent University 相似文献
95.
96.
Previous theories of intrinsic motivation have traditionally ignored the experiential or subjective aspects of engagement in intrinsically and extrinsically motivated tasks. Part of the reason for the lack of research in this area was our ignorance of which emotions to study. Data are presented here from two studies designed to produce the first systematic evidence of changes in basic emotional states during task engagement. Our findings suggest that intrinsic and extrinsic tasks can be differentiated according to the emotional changes subjects retrospectively report about their engagement with these tasks, and point the way to future research incorporating emotion as an important variable to consider.The first author was supported in part by a Minority Fellowship administered by the American Psychological Association under a Clinical Training Grant from the National Institute of Mental Health (5 T01 MH13833), and by a Regents Fellowship from the University of California, Berkeley. 相似文献
97.
David Widerker 《Erkenntnis》1988,28(2):269-291
I would like to thank Eddy Zemach, Jonathan Stavi, Julius Moravcsik and Dov Gabbay for some very good discussions on the logical form of action sentences. Also, I am indebted to an anonymous referee of Erkenntnis for some very helpful comments on an earlier draft of this paper. 相似文献
98.
M J Nissen J L Ross D B Willingham T B Mackenzie D L Schacter 《Brain and cognition》1988,8(1):117-134
We studied an individual with multiple personality disorder in whom each of several personalities claimed to have no direct awareness of the others and to be unable to consciously remember the experiences of other personalities. A broad selection of implicit and explicit memory tests was used to determine the extent to which one personality had access to knowledge acquired by another and the circumstances in which that knowledge would be expressed. The implicit assessment of memory was a necessary but not sufficient condition for demonstrating interpersonality access. The degree of compartmentalization of knowledge in this patient depended largely on whether the interpretation of presented information was likely to differ across personalities. 相似文献
99.
Studies of psychosocial influences on coronary artery atherogenesis in cynomolgus monkeys 总被引:1,自引:0,他引:1
The cynomolgus macaque provides a suitable primate model for studying how psychosocial factors contribute to coronary artery atherogenesis. Important interactions with diet, sex, and behaviorally elicited cardiovascular reactivity are described. 相似文献
100.
S R Hursh T G Raslear D Shurtleff R Bauman L Simmons 《Journal of the experimental analysis of behavior》1988,50(3):419-440
Laboratory studies of consumer demand theory require assumptions regarding the definition of price in the absence of a medium of exchange (money). In this study we test the proposition that the fundamental dimension of price is a cost-benefit ratio expressed as the effort expended per unit of food value consumed. Using rats as subjects, we tested the generality of this "unit price" concept by varying four dimensions of price: fixed-ratio schedule, number of food pellets per fixed-ratio completion, probability of reinforcement, and response lever weight or effort. Two levels of the last three factors were combined in a 2 x 2 x 2 design giving eight groups. Each group was studied under a series of six FR schedules. Using the nominal values of all factors to determine unit price, we found that grams of food consumed plotted as a function of unit price followed a single demand curve. Similarly, total work output (responses x effort) conformed to a single function when plotted in terms of unit price. These observations provided a template for interpreting the effects of biological factors, such as brain lesions or drugs, that might alter the cost-benefit ratio. 相似文献