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   2304篇
  免费   75篇
  2018年   23篇
  2017年   22篇
  2016年   36篇
  2015年   21篇
  2014年   26篇
  2013年   240篇
  2012年   56篇
  2011年   61篇
  2010年   41篇
  2009年   59篇
  2008年   56篇
  2007年   69篇
  2006年   53篇
  2005年   51篇
  2004年   67篇
  2003年   67篇
  2002年   73篇
  2001年   32篇
  2000年   40篇
  1999年   32篇
  1998年   37篇
  1997年   36篇
  1996年   28篇
  1995年   36篇
  1994年   36篇
  1993年   24篇
  1992年   33篇
  1991年   28篇
  1990年   32篇
  1989年   26篇
  1988年   27篇
  1987年   25篇
  1986年   31篇
  1985年   29篇
  1984年   40篇
  1983年   39篇
  1982年   37篇
  1981年   53篇
  1980年   42篇
  1979年   49篇
  1978年   39篇
  1977年   36篇
  1976年   47篇
  1975年   51篇
  1974年   50篇
  1973年   43篇
  1972年   22篇
  1971年   30篇
  1969年   33篇
  1968年   31篇
排序方式: 共有2379条查询结果,搜索用时 15 毫秒
951.
Perceptual masking was studied under binocular and dichoptic conditions in order to separate peripheral and central interference effects. Under binocular conditions, when the test flash (TF) and the blanking flash (BF) fell on both retinas, both retroactive and proactive masking were demonstrated. Under dichoptic conditions, when the TF fell on one eye and the BF on the other eye, thus eliminating opportunity for intraretinal interference, there was partial retroactive perceptual masking and no proactive masking. These results suggest that binocular proactive masking is due to peripheral light adaptation, that binocular retroactive masking is due to both peripheral and central effects, and that dichoptic masking is due solely to central retrochiasmal interference. It is proposed that dichoptic retroactive perceptual masking affords a method of investigating central perception time, i.e., the time to consolidate a perceptual experience.  相似文献   
952.
Luminance thresholds for downward moving contours were measured under several conditions of adaptation. Included was one condition which desensitized visual mechanisms responsive to downward motion. Another condition exerted equal effects on both up- and down-sensitive mechanisms. Thresholds for moving contours were unaffected by exposure to contours which moved in the opposite direction. This indicates that the perception of motion does not depend upon the relative activity in oppositely tuned, directionally selective visual mechanisms.  相似文献   
953.
Rhesus monkeys were trained to make auditory frequency, intensity, and duration discriminations. Initial training was carried out with a procedure which allowed the utilization of either relational cues or absolute cues. Later tests with similar auditory parameters allowed only the utilization of relational cues. Performance on these latter tests indicated that relational rather than absolute cues had been utilized when both types were available on the frequency and intensity discrimination tasks. However, absolute rather than relational cues were apparently utilized in making duration discriminations.  相似文献   
954.
Taste profiles were obtained for 26 compounds after adaptation to distilled water and also for water after adaptation to each of the 26 compounds. Each of the four “basic tastes” was induced in water by adaptation to certain of the compounds. Compounds having similar tastes did not necessarily have similar water tastes. The results imply a peripheral locus of the water taste mechanism(s).  相似文献   
955.
Patterns were computer-generated about two prototypes to form schematic clusters of three diameters about the cluster centroids. In a schematic concept-formation task, recovery of a priori schematic class membership by Os varied inversely as physical cluster diameter, with concept acquisition across trials evidenced in only the low-cluster-diameter condition. For each 0 who failed to classify according to the schema rule, linear discriminant function analysis was applied to his classes. In all cases, O-generated classes were successfully recovered by the physical pattern features used as predictors, the mapping of these classes by the LDF exceeding that by the schema rule in accuracy at all cluster-diameter levels.  相似文献   
956.
Users of interobserver agreement statistics have heretofore ignored the problem of autocorrelation in behavior sequences when testing the statistical significance of agreement measures. Due to autocorrelation traditional reliability tests based on the 2 × 2 contingency-table model (e.g., kappa, phi) are incorrect. Correct tests can be developed by using the bivariate time series as a statistical model. Seen from this perspective, testing the significance of interobserver agreement becomes formally equivalent to testing the significance of the lag-zero cross-correlation between two time series. The robust procedure known as the jackknife is suggested for this purpose.  相似文献   
957.
958.
The moments of a nonnegative bounded waveform (e.g., bounded probability density functions or responses that can be expressed as bounded probability density functions) provide the basis for characterizing the waveform. Traditionally, only the lower-order moments (k ≤ 4) have been utilized in deriving topographical indices of these waveforms. Recent advances in waveform moment analysis, however, have made it possible to derive comprehensive and interpretable indices of complex nonnegative bounded waveforms by utilizing both lower-order and higher-order moments. Waveform moment analysis is reviewed briefly, and a flexible and efficient computer program is presented for conducting waveform moment analyses.  相似文献   
959.
“Same” and “different” responses to stimuli that result in strong and weak single phenomenal wholes were investigated. Present and also previous results indicate that strong phenomenal wholes tend to be associated with a fast “same” and slow “different” response pattern. This result suggests that the parts of strong phenomenal wholes are perceived as more similar (e.g., because it should be easier to respond “same” to more similar stimuli). This suggestion is consistent with results based on other measures of perceived similarity. Present and also previous results additionally indicate that strong phenomenal wholes are frequently associated with superior overall (“same” plus “different”) performance. This result is consistent with evidence that the identification of simultaneously occurring multiple targets improves when they belong to the same phenomenal whole. The present results also hint that attention can affect whether two or three objects form the effective (functional) whole and support the assimilation explanation of the Müller Lyer illusion.  相似文献   
960.
The cross-cultural validity of a North American personality inventory, namely, the Personality Research Form (Jackson 1984) was examined using 394 university students in the Philippines who were able to speak and read English. Scale validities, with self and peer ratings as criteria, were generally significant but modest. Moderate scale and peer rating reliabilities probably contributed to these results. Elevated scores on a PRF scale designed to detect careless responding suggested failure to understand instructions or insufficient motivation may also account for the findings. Interestingly, recalculating validities for subsamples comprising ‘dependable’ and ‘undependable’ subjects yielded no substantial differences in overall validity. Implications for cross-cultural personality assessment are discussed.  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