首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   85968篇
  免费   3556篇
  国内免费   45篇
  89569篇
  2020年   999篇
  2019年   1188篇
  2018年   1692篇
  2017年   1689篇
  2016年   1800篇
  2015年   1278篇
  2014年   1540篇
  2013年   7378篇
  2012年   2884篇
  2011年   2915篇
  2010年   1766篇
  2009年   1864篇
  2008年   2503篇
  2007年   2548篇
  2006年   2285篇
  2005年   1946篇
  2004年   1968篇
  2003年   1905篇
  2002年   1859篇
  2001年   2700篇
  2000年   2599篇
  1999年   1973篇
  1998年   943篇
  1997年   879篇
  1996年   909篇
  1995年   887篇
  1994年   820篇
  1993年   842篇
  1992年   1628篇
  1991年   1504篇
  1990年   1484篇
  1989年   1403篇
  1988年   1408篇
  1987年   1303篇
  1986年   1287篇
  1985年   1387篇
  1984年   1158篇
  1983年   1064篇
  1982年   827篇
  1979年   1211篇
  1978年   903篇
  1976年   822篇
  1975年   959篇
  1974年   1111篇
  1973年   1144篇
  1972年   991篇
  1971年   889篇
  1968年   991篇
  1967年   873篇
  1966年   828篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Individuals with brain damage often encounter visual perceptual and visuo-motor difficulties. Studies have indicated an improvement in exceptional individuals' performances when the colors of figure-ground materials were reversed. Effects of reversals were studied for spastic cerebral palsied and normal children's scores on the Developmental Test of Visual-motor Integration and the Motor-free Visual Perception Test. Normal children performed better than the cerebral palsied children on all tests; the cerebral palsied children performed best on the reversed-format Motor-free Visual Perception Test. Reversal affected neither group's scores on visual-motor integration.  相似文献   
962.
Evidence relating to the hypothesis on facial feedback which ties the experience of discrete emotions to feedback from innately patterned facial expressions is discussed. Strong evidence is deduced for a more general form of the hypothesis, but the requirements of necessity and sufficiency representing the strictest form are only satisfied within narrow limits of experimental manipulations which are not common to all investigations. Evidence is deemed to support a relationship between facial expression and emotion, but facial expression is regarded as one of many systems and cannot be assigned an exclusive role (either as first system or as necessary system).  相似文献   
963.
The relationship between cognitive style and illusion magnitude was examined using the assimilation and contrast Delboeuf distortions. As in previous research, field dependence correlated positively with assimilation; however, a significant negative correlation with contrast was also found, suggesting that, while field dependence may involve the illusory integration of the stimulus field, field independence may involve its equally illusory differentiation.  相似文献   
964.
965.
Using a psychological test battery for registration of psychic/psychomotoric speed and flexibility/perseveration we examined 78 epileptic patients with different forms of epilepsy and the same number of brain healthy control persons, parallelised in sex, age, education, profession and intelligence. The registrated data were varianz-, correlation- and factoranalised. We found a deceleration of psychic/psychomotoric speed as a primary basic disorder in epileptics. Decreases of flexibility independent of speed were not ascertainable.  相似文献   
966.
967.
968.
Rats were given backward pairings of a tone (CS) and shock (US) and were then tested for response to the CS in a lick suppression test. Animals given a cuing or reminder treatment prior to the test exhibited enhanced suppression in the presence of the tone relative to a variety of control conditions. The cue-induced suppression enhancement did not appear to result from sensitization or short-term motivational changes nor did it seem to depend on second-order conditioning of the test context. The effect appeared more robust as the number of backward conditioning trials preceding the cue increased. The results were discussed in terms of current explanations of backward conditioning effects.  相似文献   
969.
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   
970.
Two experiments examined pigeons' response rates during short trials signaled by stimuli closely spaced along a wavelength continuum. In Experiment 1 separate halves of the continuum were correlated with different reinforcement schedules. In Experiment 2, the middle stimulus was accompanied by a lower probability of reinforcement than were the remaining wavelengths. Both procedures resulted in dimensional contrast “shoulders,” seen as relatively enhanced or depressed response rates in the presence of stimuli between the extreme of the continuum and the border separating the positive and negative stimuli. Sequential analyses addressed possible contributions of the following interactions: (a) local contrast, seen when rate during a given schedule depends on the schedule in the just-preceding trial; (b) modification of local contrast by the similarity of the signaling stimuli (P. Blough, 1983); and (c) schedule-independent rate contrast, seen when rate in a given trial depends on the rate controlled by the stimulus that accompanied the just-preceding trial (Malone & Rowe, 1981). Dimensional contrast functions were similar when isolated according to the schedule, to the similarity of the signaling stimulus, and to the response rate of the just-preceding trial. The interactions noted above do not appear to make important contributions to this effect.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号