全文获取类型
收费全文 | 60981篇 |
免费 | 1667篇 |
国内免费 | 27篇 |
出版年
2020年 | 436篇 |
2019年 | 571篇 |
2018年 | 4028篇 |
2017年 | 3388篇 |
2016年 | 2987篇 |
2015年 | 770篇 |
2014年 | 785篇 |
2013年 | 3591篇 |
2012年 | 1857篇 |
2011年 | 3583篇 |
2010年 | 3219篇 |
2009年 | 2318篇 |
2008年 | 2797篇 |
2007年 | 3263篇 |
2006年 | 1163篇 |
2005年 | 1198篇 |
2004年 | 1121篇 |
2003年 | 1043篇 |
2002年 | 1017篇 |
2001年 | 1243篇 |
2000年 | 1274篇 |
1999年 | 942篇 |
1998年 | 508篇 |
1997年 | 470篇 |
1996年 | 454篇 |
1995年 | 455篇 |
1994年 | 428篇 |
1992年 | 776篇 |
1991年 | 725篇 |
1990年 | 688篇 |
1989年 | 659篇 |
1988年 | 659篇 |
1987年 | 605篇 |
1986年 | 609篇 |
1985年 | 676篇 |
1984年 | 579篇 |
1983年 | 563篇 |
1982年 | 474篇 |
1981年 | 417篇 |
1980年 | 417篇 |
1979年 | 604篇 |
1978年 | 483篇 |
1977年 | 450篇 |
1976年 | 467篇 |
1975年 | 505篇 |
1974年 | 578篇 |
1973年 | 606篇 |
1972年 | 505篇 |
1968年 | 495篇 |
1967年 | 428篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
931.
M. B. Sterman J. J. Lynch M. T. Orne D. Paskewitz J. Costello N. Nicolov O. Diankov M. Popova E. Tsvetanska Robert G. Grenell J. J. Izquierdo V. H. Mark Joseph Germana N. Zill William P. Paré Joseph E. O. Newton George C. Offutt Walter Ehrlich Joseph E. D. Newton Julij Tosef J. Perez-Cruet Chester R. Wilpizeski John F. Lontz Andrew Livingston Joseph W. Cullen Samuel A. Corson Herman R. Weed Elizabeth O. Corson O. D. Murphree Paul N. Morgan Ruth Jarman J. Antal T. A. Ban J. V. Ananth H. E. Lehmann A. Ulric Moore Richard H. Barnes Wilson G. Pond 《Integrative psychological & behavioral science》1970,5(3):185-193
932.
In a genetic analysis of PTC taste sensitivity of mice, Ss were presented tap water and a PTC solution in a two-choice situation. A preference index was used as a measure of taste sensitivity, assuming that ability to taste would lead to avoidance, i.e., negative preference. This assumption, however, lead to the rejection of seven Ss who preferred the test solution. Due to the undesirability of deleting Ss, the data were reanalyzed, using an alternative index of taste sensitivity that required no assumption concerning the hedonic quality of the test solution. Information regarding the inheritance of taste sensitivity to PTC provided the validating criterion for this measure. 相似文献
933.
This investigation examined the effect of sense modality switching ofinformation at various positions of a serial learning task. Different numbers of flashes of light and different numbers of “blips” ofa pure tone were used as signalsin a four-position serial learning task. The design of the study involved a switch in sense modality at each one of the four possible positions in the series. Thus, it was possible to determine if the transmission of information through one sense modality makes it progressively more difficult or more time consuming to switch to another source of information transmitted through another modality. The results generally supported the contention that, as information is received through a particular modality, there is a build-up of the disruption involved in switching sense modality. 相似文献
934.
The effect of a fading procedure upon the acquisition of control by an overshadowed auditory feature
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)
Pigeons' key-pecking responses were reinforced in the presence of a compound stimulus that consisted of an auditory feature (a tone) and a visual feature (a light) and non-reinforced in the presence of a compound stimulus that was either a noise and a dark key, or noise and a light. In the condition where reinforcement trials differed from non-reinforcement trials on the basis of both auditory and visual features, the tone exerted very little control over responding on test. In the condition where reinforcement differed from non-reinforcement trials solely on the basis of the auditory features, an abrupt and a gradual introduction of the visual feature of the negative stimulus, a light, were compared for their effect upon control in the compounds. The tone acquired strong control in both cases. Evidence indicated that the tone had acquired control in the gradual condition without the occurrence of responses to the negative stimulus. An incidental finding was that when the negative stimulus consisted of a noise and a light, which was introduced abruptly, responding over the light dimension with tone, on test, was peaked at a point other than that light value used as positive and negative during training. 相似文献
935.
936.
937.
938.
939.
940.