全文获取类型
收费全文 | 37916篇 |
免费 | 1502篇 |
国内免费 | 24篇 |
出版年
2020年 | 420篇 |
2019年 | 434篇 |
2018年 | 658篇 |
2017年 | 700篇 |
2016年 | 702篇 |
2015年 | 496篇 |
2014年 | 592篇 |
2013年 | 2895篇 |
2012年 | 1147篇 |
2011年 | 1259篇 |
2010年 | 760篇 |
2009年 | 707篇 |
2008年 | 998篇 |
2007年 | 965篇 |
2006年 | 870篇 |
2005年 | 765篇 |
2004年 | 757篇 |
2003年 | 704篇 |
2002年 | 753篇 |
2001年 | 1342篇 |
2000年 | 1345篇 |
1999年 | 953篇 |
1998年 | 425篇 |
1997年 | 376篇 |
1992年 | 777篇 |
1991年 | 701篇 |
1990年 | 739篇 |
1989年 | 713篇 |
1988年 | 687篇 |
1987年 | 658篇 |
1986年 | 680篇 |
1985年 | 689篇 |
1984年 | 543篇 |
1983年 | 492篇 |
1982年 | 352篇 |
1981年 | 332篇 |
1979年 | 553篇 |
1978年 | 420篇 |
1977年 | 369篇 |
1976年 | 338篇 |
1975年 | 510篇 |
1974年 | 594篇 |
1973年 | 535篇 |
1972年 | 505篇 |
1971年 | 434篇 |
1970年 | 400篇 |
1969年 | 504篇 |
1968年 | 540篇 |
1967年 | 470篇 |
1966年 | 494篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
982.
Eye-movement latency as a function of age, stimulus uncertainty, and position in the visual field 总被引:2,自引:0,他引:2
L K Miller 《Perceptual and motor skills》1969,28(2):631-636
983.
984.
985.
Experiments with pigeons and rats showed that: (1) When a brief blackout was presented in lieu of reinforcement at the end of 25% of intervals on a fixed-interval 2-min schedule, response rate was reliably and persistently higher during the following 2-min intervals (omission effect). This effect was largely due to a decrease in time to first response after reinforcement omission. (2) When blackout duration was varied, within sessions, over the range 2 to 32 sec, time to first response was inversely related to the duration of the preceding blackout, for pigeons, and for rats during the first few sessions after the transition from FI 2-min to FI 2-min with reinforcement omission. Post-blackout pause was independent of blackout duration for rats at asymptote. These results were interpreted in terms of differential depressive effects of reinforcement and blackout on subsequent responding. 相似文献
986.
Effects of instructions and reinforcement-feedback on human operant behavior maintained by fixed-interval reinforcement 总被引:10,自引:10,他引:0 下载免费PDF全文
In three experiments, human subjects were trained on a five-component multiple schedule with different fixed intervals of monetary reinforcement scheduled in the different components. Subjects uninstructed about the fixed-interval schedules manifested high and generally equivalent rates regardless of the particular component. By comparison, subjects given instructions about the schedules showed orderly progressions of rates and temporal patterning as a function of the interreinforcement intervals, particularly when feedback about reinforcement was delivered but also when reinforcement-feedback was withheld. Administration of the instructions-reinforcement combination to subjects who had already developed poorly differentiated behavior, however, did not make their behavior substantially better differentiated. When cost was imposed for responding, both instructed and uninstructed subjects showed low and differentiated rates regardless of their prior histories. It was concluded that instructions can have major influences on the establishment and maintenance of human operant behavior. 相似文献
987.
Weisman RG 《Journal of the experimental analysis of behavior》1969,12(3):443-450
Interspersed reinforcement and extinction during discrimination learning generate a U-shaped gradient of inhibition about the stimulus correlated with extinction. The present work showed that extinction is not a necessary determinant of inhibitory stimulus control. In Exp. I, a reduction in the rate of reinforcement, through a shift from a multiple variable-interval 1-min variable-interval 1-min schedule to a multiple variable-interval 1-min variable-interval 5-min schedule, resulted in a post-discrimination line orientation gradient of inhibition about the stimulus correlated with the variable-interval 5-min schedule. In Exp. II, the rates of reinforcement, correlated with a pair of stimuli, were held constant during a shift from a multiple variable-interval 1-min variable-interval 1-min schedule to a multiple variable-interval 1-min differential-reinforcement-of-low-rate schedule. Inhibitory stimulus control about the stimulus correlated with the differential reinforcement of low rate was obtained. In both experiments, a reduction in the rate of responding during one stimulus and behavioral contrast during the other stimulus preceded the observation of inhibitory stimulus control. 相似文献
988.
989.
990.