全文获取类型
收费全文 | 53466篇 |
免费 | 1064篇 |
国内免费 | 5篇 |
专业分类
54535篇 |
出版年
2020年 | 554篇 |
2019年 | 655篇 |
2018年 | 922篇 |
2017年 | 910篇 |
2016年 | 943篇 |
2015年 | 648篇 |
2014年 | 856篇 |
2013年 | 3825篇 |
2012年 | 1526篇 |
2011年 | 1652篇 |
2010年 | 949篇 |
2009年 | 1016篇 |
2008年 | 1442篇 |
2007年 | 1426篇 |
2006年 | 1331篇 |
2005年 | 1167篇 |
2004年 | 1150篇 |
2003年 | 1081篇 |
2002年 | 1076篇 |
2001年 | 1678篇 |
2000年 | 1599篇 |
1999年 | 1231篇 |
1998年 | 607篇 |
1997年 | 512篇 |
1992年 | 980篇 |
1991年 | 916篇 |
1990年 | 943篇 |
1989年 | 897篇 |
1988年 | 874篇 |
1987年 | 815篇 |
1986年 | 855篇 |
1985年 | 949篇 |
1984年 | 754篇 |
1983年 | 690篇 |
1982年 | 556篇 |
1981年 | 519篇 |
1979年 | 802篇 |
1978年 | 602篇 |
1977年 | 496篇 |
1976年 | 530篇 |
1975年 | 701篇 |
1974年 | 795篇 |
1973年 | 822篇 |
1972年 | 650篇 |
1971年 | 596篇 |
1970年 | 566篇 |
1969年 | 602篇 |
1968年 | 743篇 |
1967年 | 646篇 |
1966年 | 661篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
221.
Human figure drawings of 12 pediatric oncology patients were significantly smaller in height, width, and area than were drawings of 12 school children and 12 pediatric general surgery patients paired for sex and age. The Goodenough-Harris scores of the cancer patients' drawings were also significantly lower than those of both school and general surgery groups. It is hypothesized that anxiety, lowered self-esteem, and the effects of chemotherapy contributed to these findings. 相似文献
222.
Subjects in a prior study of complex learning often experienced difficulty in mastering the task because of an apparent reluctance to release one perceptual field and reconstrue the task on a higher cognitive level. It was hypothesized that were this the correct explanation, the faster learners would be more field independent on a measure of field dependence, since independence has been defined in terms of ease in releasing one's attention from the immediate perceptual field. This hypothesis was tested with 22 undergraduate subjects for whom Group Embedded Figures Test scores were correlated with the number of trials to completion on the complex learning task. A moderate but significant correlation supported the hypothesis. 相似文献
223.
Effects of presentation complexity on rapid-sequential reading 总被引:1,自引:0,他引:1
224.
40 women were taught to use self-statements to cope with pain caused by ice water. The trainer used four different strategies for reassigning a homework task of using self-statements to cope with pain produced by immersing one hand in ice water. The strategies were equally effective in eliciting compliance with the homework assignment. 相似文献
225.
226.
White KG Pipe ME McLean AP Redman S 《Journal of the experimental analysis of behavior》1985,44(2):207-215
Distributions of reinforcers between two components of multiple variable-interval schedules were varied over a number of conditions. Sensitivity to reinforcement, measured by the exponent of the power function relating ratios of responses in the two components to ratios of reinforcers obtained in the components, did not differ between conditions with 15-s or 60-s component durations. The failure to demonstrate the “short-component effect,” where sensitivity is high for short components, was consistent with reanalysis of previous data. With 60-s components, sensitivity to reinforcement decreased systematically with time since component alternation, and was higher in the first 15-s subinterval of the 60-s component than for the component whose total duration was 15 s. Varying component duration and sampling behavior at different times since component transition may not be equivalent ways of examining the effects of average temporal distance between components. 相似文献
227.
228.
M J Howes J E Hokanson D A Loewenstein 《Journal of personality and social psychology》1985,49(4):1110-1113
Scores on the Beck Depression Inventory (BDI) were periodically obtained from the roommates of college students who exhibited a persistent mild depression over a 3-month period. For comparative purposes, BDI scores were also obtained from roommates of individuals who were transiently depressed and from subjects with nondepressed roommates. In comparison with control subjects, the roommates of persistently depressed persons displayed a progressive increase in BDI score over the course of the study. 相似文献
229.
Pigeons' not pecking or pecking constituted choice between a delayed, large reinforcer and an immediate, small reinforcer (self-control) and at other times between a delayed reinforcer and no reinforcer (omission). Both a tone and a keylight were tested as choice signals, and the delayed reinforcer was either response independent or response dependent. Pigeons pecked during the choice signals on over 95% of the trials in the self-control procedure, and pecked during the choice signals on over 75% of the trials in the omission procedure. Consistent pecking was observed with either the tone or the keylight as a choice signal, with the exception that a tone paired with a response-independent delayed reinforcer did not maintain pecking in the omission procedure. Pigeons pecked during more choice signals when delayed reinforcers were response dependent than when the delayed reinforcers were response independent. These results indicate that Pavlovian conditioning influences self-control experiments, especially in single-key procedures. 相似文献
230.
The following survey is intended to demonstrate and discuss some principle problems of biomagnetism and the application in clinical fields. The development of special technical parameters especially by the SQUID method is initiating new possibilities of research and completing the neurobiologically determinated basis and conditions of neuropsychiatric disorders. The Magnetoencephalography (MEG) will be represent an important role of a new functional diagnostic method. 相似文献