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   58378篇
  免费   976篇
  国内免费   5篇
  59359篇
  2020年   623篇
  2019年   732篇
  2018年   1000篇
  2017年   1112篇
  2016年   1127篇
  2015年   773篇
  2014年   963篇
  2013年   4356篇
  2012年   1787篇
  2011年   1824篇
  2010年   1179篇
  2009年   1095篇
  2008年   1597篇
  2007年   1614篇
  2006年   1433篇
  2005年   1280篇
  2004年   1217篇
  2003年   1153篇
  2002年   1188篇
  2001年   1755篇
  2000年   1727篇
  1999年   1335篇
  1998年   607篇
  1997年   570篇
  1993年   526篇
  1992年   1102篇
  1991年   989篇
  1990年   1065篇
  1989年   957篇
  1988年   977篇
  1987年   932篇
  1986年   948篇
  1985年   921篇
  1984年   798篇
  1983年   742篇
  1982年   568篇
  1981年   533篇
  1979年   898篇
  1978年   648篇
  1977年   575篇
  1975年   749篇
  1974年   822篇
  1973年   854篇
  1972年   675篇
  1971年   642篇
  1970年   573篇
  1969年   679篇
  1968年   784篇
  1967年   705篇
  1966年   649篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
281.
Improvement in auditory-successive selective attention was noted across the age range of 9 through 16 yr. In contrast to comparable paradigms with visual-simultaneous materials, 30 learning disabled and 30 normal boys did not differ. Results of research on selective attention may be affected by task materials and encoding requirements.  相似文献   
282.
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   
283.
The present experiments studied a three-event delayed sequence-discrimination (DSD) task: one arrangement (order) of two stimuli (red and yellow overhead lights) taken three in succession (e.g., red, yellow, red) was the positive sequence and the remaining seven arrangements were the negative sequences for responding and reward during the subsequent test stimulus. In Experiment 1, the final stimulus (recency) and the order of stimuli in the positive sequence controlled acquisition of discrimination. In Experiment 2, increasing the duration of memory intervals between stimuli reduced the discriminability of those negative sequences identical to the positive sequence after the delay. Three-event DSD performance in Experiments 1 and 2 was similar to two-event DSD performance in comparable published experiments. Models developed to explain pigeon performance in two-event DSD were extended to the three-event task. Results from both two- and three-event versions of the DSD task falsified a noncumulative model and several cumulative integration models (i.e., adding, averging, and some multiplying models), but corroborated one cumulative, multiplying model.  相似文献   
284.
The following survey is intended to demonstrate and discuss some principle problems of biomagnetism and the application in clinical fields. The development of special technical parameters especially by the SQUID method is initiating new possibilities of research and completing the neurobiologically determinated basis and conditions of neuropsychiatric disorders. The Magnetoencephalography (MEG) will be represent an important role of a new functional diagnostic method.  相似文献   
285.
The author presents the case of a patient who showed the massive defensive effects seen in people who were abused in childhood. These effects are similar to those described in George Orwell's 1984 and in his autobiographical writings: denial and "doublethink"; masochistic submission to the tormentor; turning of anger against the self and loving "Big Brother"; identifying with the abuser and tormenting others; a burgeoning of anal mechanisms and obsessive phenomena that results in a massive isolation of affects; excessive emotional control alongside outbursts of rage. The interference with memory and emotions compromises identity and humanity. The unforseeable evolution of innate gifts in a child sometimes permits a partial transcendence of these crippling defenses, as Orwell partially transcended what appears to have been the emotional deprivation of his childhood and what he felt to have been the abuse of his schoolboy years.  相似文献   
286.
Additional results from Rutte and Wilke's (1984) study are presented. In the context of a social dilemma situation two variables were manipulated: use and variance. Preference for various decision structures is the issue of the present paper. It appeared that a large majority structure and an unanimity structure were mast preferred. A small majority structure and a structure in which each decides for him/herself were intermediately preferred. Whereas a structure in which one person, a leader, decides for all was least preferred. Further analysis of these data suggested that only the latter two decision structures were influenced by the use and variance manipulations.  相似文献   
287.
Analyses of averaged auditory evoked responses to a list of 10 positive and 10 negative words led to the identification of a restricted region in the brain response which reliably discriminated between words differing in the semantic features positive and negative. These data support the view that word meanings are composed of more basic components or features and are not stored simply as dictionary items in the brain.  相似文献   
288.
This study examined two issues related to the use of nonprofessional counselors (n = 159) within the context of a diversion program for juvenile offenders. First, the relationship of the nonprofessionals' personality traits and general attitudes to client outcome was examined. No statistically significant correlations were observed. Second, the differential impact of various training and supervision factors was examined in terms of nonprofessional satisfaction, attitudes, and locus of control. Results suggested that training intensity, training content, and supervision setting may influence nonprofessionals' attitudes towards various social groups and their satisfaction with the nonprofessional experience.  相似文献   
289.
290.
Phenomena of language teaching and learning in the course of verbal interactions between one mother and her daughter were analyzed. The daughter was between 18 and 27 months old during the recordings, and her utterance length ranged from 1,5 to 4,0 morphemes. Twenty hours of interactions were analyzed and the emphasis was placed upon sequential aspects and mathemagenic features of the conversations. It was demonstrated that the mother performs much analytic, synthetic, abstracting, and word-class-defining work during these verbal interactions. These maternal instructional activities seem to lead not only to the child's learning of language rules but also to her employment of the abstracting, analytical, and synthetic methodology. It is concluded that the main explanatory focus has to be on the mother in the attempts to explain language transmission and acquisition. Basic similarities to other instructional/skill training situations are suggested. Neither extraordinary complex cognitive nor innate linguistic capacities need to be assumed to explain the phenomena in question.  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