全文获取类型
收费全文 | 17531篇 |
免费 | 1475篇 |
国内免费 | 1030篇 |
出版年
2024年 | 38篇 |
2023年 | 281篇 |
2022年 | 250篇 |
2021年 | 292篇 |
2020年 | 609篇 |
2019年 | 648篇 |
2018年 | 622篇 |
2017年 | 706篇 |
2016年 | 718篇 |
2015年 | 445篇 |
2014年 | 614篇 |
2013年 | 1934篇 |
2012年 | 369篇 |
2011年 | 453篇 |
2010年 | 381篇 |
2009年 | 583篇 |
2008年 | 773篇 |
2007年 | 820篇 |
2006年 | 775篇 |
2005年 | 649篇 |
2004年 | 563篇 |
2003年 | 478篇 |
2002年 | 451篇 |
2001年 | 282篇 |
2000年 | 260篇 |
1999年 | 222篇 |
1998年 | 177篇 |
1997年 | 151篇 |
1996年 | 122篇 |
1995年 | 117篇 |
1994年 | 107篇 |
1993年 | 82篇 |
1992年 | 66篇 |
1991年 | 45篇 |
1990年 | 48篇 |
1988年 | 40篇 |
1987年 | 26篇 |
1985年 | 372篇 |
1984年 | 416篇 |
1983年 | 344篇 |
1982年 | 449篇 |
1981年 | 441篇 |
1980年 | 443篇 |
1979年 | 394篇 |
1978年 | 444篇 |
1977年 | 350篇 |
1976年 | 353篇 |
1975年 | 272篇 |
1974年 | 278篇 |
1973年 | 236篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
241.
R Dunn 《Journal of the experimental analysis of behavior》1990,53(1):163-174
Response-contingent timeouts of equal duration and frequency were added to both alternatives of unequal concurrent schedules of reinforcement. For each of 4 pigeons in Experiment 1, relative response rates generally became less extreme as the frequency of timeout increased. In Experiment 2, relative response rates consistently approached indifference as the duration of timeout was increased. Variation in time allocation was less consistent in both experiments. Absolute response rates did not vary with the timeout contingency in either experiment. In a third experiment, neither measure of choice varied systematically when the duration of a postreinforcement blackout was varied. In contrast to the present results, preference has been shown to vary directly with the parameters of shock delivery in related procedures. The pattern of results in the first two experiments follows that obtained with other manipulations of the overall rate of reinforcement in concurrent schedules. The results of the third experiment suggest that an intertrial interval following reinforcement is not a critical feature of the overall rate of reinforcement. 相似文献
242.
Determinants of pigeons' waiting time: Effects of interreinforcement interval and food delay
下载免费PDF全文
![点击此处可从《Journal of the experimental analysis of behavior》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Manabe K 《Journal of the experimental analysis of behavior》1990,53(1):123-132
Four pigeons performed on three types of schedules at short (i.e., 10, 30, or 60 s) interreinforcement intervals: (a) a delay-dependent schedule where interreinforcement interval was held constant (i.e., increases in waiting time decreased food delay), (b) an interreinforcement-interval-dependent schedule where food delay was held constant (i.e., increases in waiting time increased interreinforcement interval), and (c) a both-dependent schedule where increases in waiting time produced increases in interreinforcement interval but decreases in food delay. Waiting times were typically longer under the delay-dependent schedules than under the interreinforcement-interval-dependent schedules. Those under both-dependent schedules for 1 subject were intermediate between those under the other two schedule types, whereas for the other subjects waiting times under the both-dependent procedure were similar either to those under the delay-dependent schedule or to those under the interreinforcement-interval-dependent schedule, depending both on the subject and the interreinforcement interval. These results indicate that neither the interreinforcement interval nor food delay is the primary variable controlling waiting time, but rather that the two interact in a complex manner to determine waiting times. 相似文献
243.
A two-facet measurement model with broad application in the behavioral sciences is identified, and its coefficient of generalizability (CG) is examined. A normalizing transformation is proposed, and an asymptotic variance expression is derived. Three other multifaceted measurement models and CGs are identified, and variance expressions are presented. Next, an empirical investigation of the procedures follows, and it is shown that, in most cases, Type I error control in inferential applications is precise, and that the estimates are relatively efficient compared with the correlation coefficient. Implications for further research and for practice are noted. In an Appendix, four additional models, CGs, and variance expressions are presented.The research reported herein formed part of a doctoral dissertation conducted by Marsha Schroeder (Schroeder, 1986), under the direction of Ralph Hakstian, at the University of British Columbia. We acknowledge with thanks the contributions to this research of Todd Rogers and James Steiger. We are also very indebted to an mous reviewer who provided some important clarifications in connection with two of the models considered. Some support for this research was provided by a grant to Ralph Hakstian from the Natural Sciences and Engineering Research Council of Canada. 相似文献
244.
Raphael Sassower 《Studies in Philosophy and Education》1990,10(3):251-261
This paper suggests that medical education be revised to assist in diffusing potential ethical dilemmas that arise during health care provision. A revised medical education would emphasize the role of the humanities in the training of physicians, especially in light of recent critiques of the canonical scientific model in general, and more specifically in the use of that model for medical training and practice.I wish to thank Dr. Mary Ann Cutter and Melissa M. Amaro for their critical suggestions. 相似文献
245.
Joseph C. Pitt 《Studies in Philosophy and Education》1990,10(1):7-17
It is argued that the manner in which we teach science in the high schools represents an outdated positivistic conception of science. The standard presentation of a year of each of chemistry, biology and physics should be replaced by an integrated science plus history, philosophy, and sociology of science which would take a total of three years to complete. A proper appreciation for the true nature of science is essential to the continued health of the scientific enterprise. 相似文献
246.
Paul Chodoff 《Political psychology》1997,18(1):147-157
The Nazi Holocaust has had continuing and widely reverberating consequences not only for the Jewish survivors but for the world at large. These consequences are detailed, first through a personal account of an Auschwitz survivor, and then through a discussion of the adaptive measures of concentration camp inmates and the long-term psychiatric and psychological effects on survivors and their families. The Survivor or Concentration Camp Syndrome and its relationship to the Post-Traumatic Stress Disorder is described. Indirect effects of the Holocaust have been manifested in various ways, particularly through various levels of psychologic denial displayed by Holocaust criminals and (at least during the early postwar period) by the German public. The Holocaust has had profound effects on the ways the Jewish people regard themselves and are seen by others. Finally, the Holocaust can be seen as offering a kind of paradigmatic signature to the worldview of the end of the 20th century, emphasizing the persistence of evil and the limitations of the idea of progress. 相似文献
247.
In this paper, we examine the termination of children's mental health services. Analyses were based on the 901 families in the Fort Bragg Evaluation Project who participated at Wave 1 and Wave 2 six months later. The project compared a full continuum of care provided at a demonstration site with traditional care at two comparison sites. The results showed that in most cases families and providers were partners in decisions to terminate treatment. About half of the clients self-terminated or were terminated solely at the discretion of the provider. Providers tended to play a more dominant role in terminating restrictive services; families played a more central role in terminating outpatient care. Regardless of initial psychopathology, children in single-headed households, whose parents were dissatisfied with services, did not expect their child to cooperate with treatment and did not expect treatment to help their child, were more likely to terminate care than others. While the Demonstration site had significantly fewer terminations, the sites did not differ with regard to the reasons for termination, who participated in termination decisions, or the factors that affected the likelihood to terminate care. Of most interest, mental health outcomes among children who had terminated all care did not vary by reasons for termination or by who participated in the termination decision. 相似文献
248.
The major challenge facing today’s biomedical researchers is the increasing competition for available funds. The competitive
review process, through which the National Institutes of Health (NIH) awards grants, is built upon review by a committee of
expert scientists. The NIH is firmly committed to ensuring that its peer review system is fair and objective.
Wendy Baldwin, Ph.D., is Deputy Director for Extramural Research, National Institutes of Health.
This paper is based on a presentation at a workshop, “Advances in Peer Review Research”, American Association for the Advancement
of Science Meeting, Baltimore, MD, February 9, 1996. 相似文献
249.
250.
本文对1—5岁汉族儿童使用双宾结构的状况进行了考察。首先对儿童语言中双宾结构的结构类型、句法功能及其发展状况进行了描述分析;在此基础上,讨论了儿童习得汉语双宾结构的机制。 相似文献