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   20483篇
  免费   944篇
  国内免费   17篇
  2021年   180篇
  2020年   311篇
  2019年   305篇
  2018年   476篇
  2017年   486篇
  2016年   496篇
  2015年   373篇
  2014年   405篇
  2013年   1726篇
  2012年   776篇
  2011年   804篇
  2010年   470篇
  2009年   449篇
  2008年   607篇
  2007年   613篇
  2006年   500篇
  2005年   436篇
  2004年   427篇
  2003年   404篇
  2002年   408篇
  2001年   775篇
  2000年   779篇
  1999年   520篇
  1998年   220篇
  1997年   205篇
  1996年   168篇
  1995年   168篇
  1993年   161篇
  1992年   395篇
  1991年   354篇
  1990年   381篇
  1989年   367篇
  1988年   342篇
  1987年   327篇
  1986年   340篇
  1985年   328篇
  1984年   264篇
  1983年   233篇
  1979年   233篇
  1978年   185篇
  1975年   221篇
  1974年   273篇
  1973年   220篇
  1972年   220篇
  1971年   182篇
  1970年   171篇
  1969年   211篇
  1968年   218篇
  1967年   173篇
  1966年   191篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
932.
The acquisition of observing.   总被引:6,自引:6,他引:0       下载免费PDF全文
Pigeons were exposed to stimuli correlated with the presence or absence of a variable-interval 60-second schedule of reinforcement only while they depressed a crossbar or "perch." In the first experiment, the stimuli were different tilts of a line displayed on the key. When the difference in brightness between the line and the background (salience) was maximal, seven of eight birds acquired the discrimination, but when the difference was reduced by 50%, only one succeeded. In the second experiment, wavelength of chamber illumination served as the relevant dimension. Neither experiment showed a large effect attributable to the magnitude of the difference (disparity) between the positive and the negative stimulus. Individual differences in time spent observing were positively correlated with level of discrimination in the presence of the stimuli. All birds produced the positive stimulus for a greater proportion of the available time than they did the negative stimulus. This may be the mechanism that provides selective reinforcement of observing. Finally, the formation of a discrimination was analyzed in terms of changes in the proportion of time spent in contact with the discriminative stimuli.  相似文献   
933.
934.
935.
Just and Carpenter (1980) presented a theory of reading based on eye fixations wherein their “psycholinguistic” variables accounted for 72% of the variance in word gaze durations. This comment raises some statistical and theoretical problems with their use of simultaneous regression analysis of gaze duration measures and with the resulting theory of reading. A major problem was the confounding of perceptual with psycholinguistic factors. New eye fixation data are presented to support these criticisms. Analysis of fixations within words revealed that most gaze duration variance was contributed by number of fixations rather than by fixation duration.  相似文献   
936.
How do we use place information in a number comparison task involving multidigit numbers? In four experiments, subjects identified stimulus numbers as larger or smaller than the number 5,000 in a choice reaction time task. As the difference between the number of places in the stimulus number and the number of places in the standard decreased, response time and errors significantly increased. When the number of places was held constant, the type of numeric information extracted depended on the value of the standard (5,000 or 5,555). In some cases, irrelevant place information affected choice time.  相似文献   
937.
938.
The fractionation of arithmetical skills: A single case study   总被引:14,自引:0,他引:14  
A single case study of a patient with a selective impairment of arithmetical calculation is reported. DRC became severely acalculic after sustaining a left parietal intra-cerebral haematoma. His numeracy skills were documented as fully as possible. It was found that his knowledge of the significance of individual numbers and his concept of quantity appeared to be intact, but simple addition, subtraction and multiplication were all performed laboriously and inaccurately and his performance was inconsistent from trial to trial. Further it was shown that it was his knowledge of arithmetical facts not his knowledge of arithmetical operations which was impaired. The findings are discussed in relation to models of arithmetical calculation and it is concluded that for DRC there was a deficit in accessing one category of verbal semantic knowledge systems, namely arithmetical facts.  相似文献   
939.
Based on an attributional analysis of menstrual distress, the present study examined how a woman is evaluated when she attributes an instance of negative social behavior to the approach or onset of menstruation. College men and women were asked to imagine an interaction in which a woman behaves very irritably and then gives one of several excuses for her negative behavior, two of which were menstrual related. Subjects evaluated each excuse in terms of (1) degree of annoyance, (2) blameworthiness, and (3) internality versus externality. The results showed consistent relationships between these evaluations and both sex of subject and general attitudes about menstruation. Males tended to see menstrual-related excuses as less blameworthy and more external than did females. In addition, general attitudes regarding the debilitating effects of menstruation predicted greater tolerance toward the use of menstrual excuses. These results are discussed in terms of their implications for the socialization and continuing reinforcement of menstrual distress.The research reported in this article was supported by grants SOC-7602137 and SOC-7602179 from the National Science Foundation. The authors wish to thank Russ Fazio for his help in collecting the data and Al Rogers and Terry Balaban for their help in analyzing the data. Diane N. Ruble is now at New York University. Ann K. Boggiano is now at the University of Colorado.  相似文献   
940.
What career decision-making procedures enable people to make decisions that yield consequences congruent with their own values? The 40 “best” (most congruent) and 40 “worst” decision makers on the Career Decision Simulation were compared in a sample of 148 community college students. No significant differences appeared in the amount of double checking, number of occupations and information sources checked, amount of information collected, decision time required, and the proportion of information sought about high values. The “best” decision makers, however, were significantly more persistent in immediately seeking more information about an occupation that seemed to match one of their most important personal work values. Following a values-guided search appears more effective than simply searching exhaustively.  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