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   52345篇
  免费   2113篇
  国内免费   15篇
  2019年   670篇
  2018年   899篇
  2017年   940篇
  2016年   971篇
  2015年   717篇
  2014年   855篇
  2013年   4014篇
  2012年   1533篇
  2011年   1612篇
  2010年   971篇
  2009年   948篇
  2008年   1352篇
  2007年   1381篇
  2006年   1262篇
  2005年   1146篇
  2004年   1110篇
  2003年   1034篇
  2002年   1078篇
  2001年   1657篇
  2000年   1525篇
  1999年   1173篇
  1998年   581篇
  1997年   493篇
  1996年   515篇
  1992年   949篇
  1991年   924篇
  1990年   895篇
  1989年   896篇
  1988年   893篇
  1987年   820篇
  1986年   855篇
  1985年   894篇
  1984年   732篇
  1983年   675篇
  1982年   533篇
  1981年   527篇
  1979年   829篇
  1978年   608篇
  1977年   508篇
  1976年   548篇
  1975年   692篇
  1974年   806篇
  1973年   837篇
  1972年   668篇
  1971年   635篇
  1970年   628篇
  1969年   630篇
  1968年   806篇
  1967年   696篇
  1966年   683篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
911.
Bandler and Grinder's hypothesis that eye-movements reflect sensory processing was examined. 28 volunteers first memorized and then recalled visual, auditory, and kinesthetic stimuli. Changes in eye-positions during recall were videotaped and categorized by two raters into positions hypothesized by Bandler and Grinder's model to represent visual, auditory, and kinesthetic recall. Planned contrast analyses suggested that visual stimulus items, when recalled, elicited significantly more upward eye-positions and stares than auditory and kinesthetic items. Auditory and kinesthetic items, however, did not elicit more changes in eye-position hypothesized by the model to represent auditory and kinesthetic recall, respectively.  相似文献   
912.
913.
In two experiments, we investigated the factors that influence the perceived similarity of speech sounds at two developmental levels. Kindergartners and second graders were asked to classify nonsense words, which were related by syllable and phoneme correspondences. The results support the existence of a developmental trend toward increased attention to individual phonemic segments. Moreover, one significant factor in determining the perceived similarity of speech sounds appears to be the position of the component correspondences; attention to the beginning of utterances may have developmental priority. An unexpected finding was that the linguistic status of the unit involved in a correspondence (whether it was a syllable or a phoneme) did not seem particularly important. Apparently, the factors which contribute to the perceived similarity of speech sounds in the classification task are not identical to those which underlie performance in explicit segmentation and manipulation tasks, since in the latter sort of task, syllables are more accessible than phonemes for young children. The present task may tap a level of processing that is closer to the one entailed in word recognition and lexical access.  相似文献   
914.
Intermediate prepositional logics we consider here describe the setI() of regular informational types introduced by Yu. T. Medvedev [7]. He showed thatI() is a Heyting algebra. This algebra gives rise to the logic of infinite problems from [13] denoted here asLM 1. Some other definitions of negation inI() lead to logicsLM n (n ). We study inclusions between these and other systems, proveLM n to be non-finitely axiomatizable (n ) and recursively axiomatizable (n < ). We also show that formulas in one variable do not separateLM from Heyting's logicH, andLM n (n < ) from Scott's logic (H+S).  相似文献   
915.
In some recent papers, the authors and Peter Gärdenfors have defined and studied two different kinds of formal operation, conceived as possible representations of the intuitive process of contracting a theory to eliminate a proposition. These are partial meet contraction (including as limiting cases full meet contraction and maxichoice contraction) and safe contraction. It is known, via the representation theorem for the former, that every safe contraction operation over a theory is a partial meet contraction over that theory. The purpose of the present paper is to study the relationship more finely, by seeking an explicit map between the component orderings involved in each of the two kinds of contraction. It is shown that at least in the finite case a suitable map exists, with the consequence that the relational, transitively relational, and antisymmetrically relational partial meet contraction functions form identifiable subclasses of the safe contraction functions, over any theory finite modulo logical equivalence. In the process of constructing the map, as the composition of four simple transformations, mediating notions of bottom and top contraction are introduced. The study of the infinite case remains open.  相似文献   
916.
This paper discusses thecompatibility of the polychotomous Rasch model with dichotomization of the response continuum. It is argued that in the case of graded responses, the response categories presented to the subject are essentially an arbitrary polychotomization of the response continuum, ranging for example from total rejection or disagreement to total acceptance or agreement of an item or statement. Because of this arbitrariness, the measurement outcome should be independent of the specific polychotomization applied, for example, presenting a specific multicategory response format should not affect the measurement outcome. When such is the case, the original polychotomous model is called compatible with dichotomization.A distinction is made between polychotomization or dichotomization before the fact, that is, in constructing the response format, and polycho- or dichotomization after the fact, for example in dichotomizing existing graded response data.It is shown that, at least in case of dichotomization after-the-fact, the polychotomous Rasch model is not compatible with dichotomization, unless a rather special condition of the model parameters is met. Insofar as it may be argued that dichotomization before the fact is not essentially different from dichotomization after the fact, the value of the unidimensional polychotomous Rasch model is consequently questionable. The impact of our conclusion on related models is also discussed.  相似文献   
917.
A family of chance-corrected association coefficients for metric scales   总被引:1,自引:0,他引:1  
A chance-corrected version of the family of association coefficients for metric scales proposed by Zegers and ten Berge is presented. It is shown that a matrix with chance-corrected coefficients between a number of variables is Gramian. The members of the chance-corrected family are shown to be partially ordered. The author is obliged to Jos ten Berge for helpful comments.  相似文献   
918.
919.
Pupillary responses have proven to be reliable physiological correlates of cognitive effort in a variety of tasks, including language processing. To investigate the relation between psychological and syntactic complexity 20 syntactically ambiguous sentences, balanced for bias, were presented to 16 subjects, while their pupil size was continuously measured. These sentences could be read as verb oriented (syntactically more complex) or object oriented (syntactically less complex). Principal components analysis of pupillary movements revealed that verb-oriented readings, resulted in greater pupillary dilations than object-oriented readings, indicating that syntactically more complex sentences, as determined via a formal grammar, require greater cognitive effort in processing. This is viewed as further evidence for the notion that syntactic and psychological complexity are related. High- and low-bias sentences did not induce comparable differences in pupillary movements, indicating that the "multiple meaning theory" may have to be modified.  相似文献   
920.
Four experiments investigated the relation between the development of binocular vision and infant spatial perception. Experiments 1 and 2 compared monocular and binocular depth perception in 4- and 5-month-old infants. Infants in both age groups reached more consistently for the nearer of two objects under binocular viewing conditions than under monocular viewing conditions. Experiments 3 and 4 investigated whether the superiority of binocular depth perception in 4-month-olds is related to the development of sensitivity to binocular disparity. Under binocular viewing conditions in Experiment 3, infants identified as disparity-sensitive reached more consistently for the nearer object than did infants identified as disparity-insensitive. The two groups' performances did not differ under monocular viewing conditions. These results suggest that, binocularly, the disparity-sensitive infants perceived the objects' distances more accurately than did the disparity-insensitive infants. In Experiment 4, infants were habituated to an object, then presented with the same object and a novel object that differed only in size. Disparity-sensitive infants showed size constancy by recovering from habituation when viewing the novel object. Disparity-insensitive infants did not show clear evidence of size constancy. These findings suggest that the development of sensitivity to binocular disparity is accompanied by a substantial increase in the accuracy of infant spatial perception.  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