全文获取类型
收费全文 | 24308篇 |
免费 | 1034篇 |
国内免费 | 13篇 |
专业分类
25355篇 |
出版年
2020年 | 288篇 |
2019年 | 286篇 |
2018年 | 477篇 |
2017年 | 442篇 |
2016年 | 468篇 |
2015年 | 304篇 |
2014年 | 414篇 |
2013年 | 1839篇 |
2012年 | 741篇 |
2011年 | 790篇 |
2010年 | 441篇 |
2009年 | 527篇 |
2008年 | 695篇 |
2007年 | 692篇 |
2006年 | 623篇 |
2005年 | 558篇 |
2004年 | 551篇 |
2003年 | 527篇 |
2002年 | 497篇 |
2001年 | 846篇 |
2000年 | 853篇 |
1999年 | 639篇 |
1998年 | 283篇 |
1997年 | 251篇 |
1996年 | 230篇 |
1995年 | 223篇 |
1992年 | 512篇 |
1991年 | 458篇 |
1990年 | 514篇 |
1989年 | 438篇 |
1988年 | 410篇 |
1987年 | 395篇 |
1986年 | 408篇 |
1985年 | 472篇 |
1984年 | 368篇 |
1983年 | 311篇 |
1982年 | 243篇 |
1979年 | 349篇 |
1978年 | 276篇 |
1977年 | 227篇 |
1975年 | 315篇 |
1974年 | 368篇 |
1973年 | 372篇 |
1972年 | 284篇 |
1971年 | 257篇 |
1970年 | 217篇 |
1969年 | 232篇 |
1968年 | 300篇 |
1967年 | 264篇 |
1966年 | 290篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
In Experiment I the response that terminated the postreinforcement pauses occurring under a fixed-interval 60-second schedule was reinforced, if the pause duration exceeded 30 seconds. The percentage of such pauses, rather than increasing, decreased. There were complex effects on the discriminative control of the pause by the reinforcer terminating the previous fixed interval, depending on whether the fixed interval and the added reinforcer were the same or different. In Experiments II(a) and II(b), each reinforcement initiated an alternative fixed-interval interresponse-time-greater-than-t-sec schedule, the schedule values being systematically varied. When the response following a pause exceeding a given duration was reinforced, fewer such pauses occurred than when they were not reinforced, i.e., on the comparable simple fixed-interval schedule. There was no systematic relationship between mean interrinforcement interval and duration of the postreinforcement pause. The pause duration initiated by reinforcement was directly related to the dependency controlling the shortest pause at that time, regardless of changes in mean interreinforcement interval. 相似文献
922.
923.
924.
Hineline PN 《Journal of the experimental analysis of behavior》1978,29(1):87-103
On avoidance procedures, rats and pigeons typically show warmup effects, characterized by improving performance within sessions and loss of the improvement (“warmup decrement”) between sessions. Between-session losses were examined by varying the time between periods of avoidance training. In one experiment, rats lived fulltime in conditioning chambers while intermission intervals were varied. In a second experiment, the animals lived in home cages between sessions; timeout intervals were introduced at midession, producing recurrence of warmup in the second half-session. In both experiments, the warmup decrements increased substantially as the timeout or intersession intervals were increased from zero to 30 minutes. With intervals of 60 or 120 minutes, the decrements approached or exceeded those obtained with intervals of a day or more. When avoidance was interposed between appetitive sessions, the appetitive responding was disrupted, but this seemed unrelated to the warmup or to the proficiency of avoidance. The warmup in avoidance shares characteristics with transient punishment effects, with the Kamin effect, and with habituation phenomena, but it is premature to assume that they reflect common processes. 相似文献
925.
926.
7 subjects, aged 19 to 25 yr., who evoked syntactic verbal material in the report made after awakening during REM sleep, were asked to reproduce it a few minutes later. No big differences had been obsered between the two recalls; all recalled verbal materials, many sentences and kernel-sentences reappeared. These results indicate a good consolidation of the material obtained after awakening during REM sleep. 相似文献
927.
928.
929.
930.
The relative effectiveness of incentive plans administered on continuous and VR-4 schedules of reinforcement was investigated with unionized employees using a within subjects design. Mountain beaver trappers working side by side were randomly assigned to one of two groups. In group A the trappers received $1.00 for every rat they trapped. At the end of four weeks, they were switched to a VR-4 schedule in which they received $4.00 contingent upon trapping a rat and correctly guessing the color of one of four marbles prior to drawing it from a bag held by the supervisor. In group B the order of the schedules was reversed. The results were analyzed in terms of cost-related, behavioral, and reaction criteria. The study increased employee productivity and decreased costs for the company. Inexperienced workers had higher productivity on the continuous reinforcement than on the VR-4 schedule; experienced workers had higher productivity on the VR-4 schedule than on the continuous schedule. Both the experienced and the inexperienced employees preferred the VR-4 schedule over the continuous schedule. 相似文献