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   163665篇
  免费   7524篇
  国内免费   158篇
  171347篇
  2021年   1490篇
  2020年   2768篇
  2019年   3432篇
  2018年   3411篇
  2017年   3863篇
  2016年   4554篇
  2015年   3911篇
  2014年   4795篇
  2013年   23458篇
  2012年   4239篇
  2011年   3258篇
  2010年   3744篇
  2009年   4681篇
  2008年   3536篇
  2007年   3045篇
  2006年   3755篇
  2005年   3752篇
  2004年   3243篇
  2003年   2901篇
  2002年   2718篇
  2001年   2891篇
  2000年   2717篇
  1999年   2881篇
  1998年   2768篇
  1997年   2631篇
  1996年   2557篇
  1995年   2390篇
  1994年   2359篇
  1993年   2320篇
  1992年   2359篇
  1991年   2215篇
  1990年   2052篇
  1989年   2002篇
  1988年   1989篇
  1987年   2015篇
  1986年   1978篇
  1985年   2192篇
  1984年   2381篇
  1983年   2177篇
  1982年   2333篇
  1981年   2297篇
  1980年   2142篇
  1979年   2001篇
  1978年   2089篇
  1977年   2078篇
  1976年   1869篇
  1975年   1853篇
  1974年   1885篇
  1973年   1757篇
  1972年   1375篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
The 16th century schism in Christian thought leading to the Reformation has an interesting analogy in Carl Rogers' attempt to reform the helping professions. An exploration of this analogy clarifies much of the theoretical tension in the contemporary arena of pastoral counseling.  相似文献   
942.
Despite importance for theories of perception, controversy exists as to whether information is available to the perceptual system about involuntary as well as voluntary eye movements. We measured the perceived direction of targets flashed briefly in an otherwise dark field during the primary phase of optokinetic afternystagmus (OKAN), an involuntary eye movement that persists in darkness following optokinetic stimulation. Perceived direction was measured by unseen pointing in one experiment and by pointing made under visual control in a second experiment. Pointing was essentially veridical in both experiments, indicating that accurate extra-retinal information about eye position (presumably, as efference copy) exists for OKAN. Illusory motion of visual targets, which can occur during involuntary oculomotor responses, therefore cannot be attributed to a lack of efference-copy signals for such eye movements.  相似文献   
943.
Test of speech-sound discrimination are used by special educators, reading specialists and speech-language pathologists in assessing children's ability to differentiate between speech sounds occurring in standard English. Such tests are important in determining if speech-sound articulation errors are caused by difficulty in making such differentiations. However, during the past 10 years, these tests have been criticized on the basis of their reliability and validity. The purpose of this study was to examine the use of two alternative methods of assessing speech-sound discrimination with a school-aged population to determine if they elicited responses in a similar manner.  相似文献   
944.
945.
H-reflex amplitudes were studied during the acquisition of a motor skill involving coordinated isometric plantarflexion at the ankle joints as subjects learned to trace a triangular pattern on an oscilloscope screen by controlling plantarflexion torque applied against load cells. Torque feedback was presented on a subject oscilloscope with the right foot controlling a vertical cursor and the left foot a horizontal cursor. Eleven subjects reached criterion performance. H-reflexes were recorded from the right soleus and timed to the initiation of soleus muscle activity to plantarflex the foot. Average time to complete one trial decreased from 9 sec. in the prelearning block to 4 sec. postlearning. No single learning strategy was evident as subjects varied widely in their levels of H-reflex amplitude, but during postlearning, H-reflex amplitude became consistent within subjects as tracing performance became faster and accurate.  相似文献   
946.
947.
Perception of global pitch motion was studied through psychoacoustic experiments with random chord sequences. Chords contained either six or eight (fixed) tone elements, being sinusoidal, sawtooth-like, or Shepard tones, which were either on or off according to a probability controlled by the experimenter. Sequences of 2, 4, 5, or 8 chords were used. Identification by subjects of the perceived direction of overall pitch motion (up or down) was found to be well accounted for by a model in which the ultimate pitch motion percept is given by a sum of contributions from selected element transitions--that is, transitions between adjoining tone elements in successive time frames only. In its simplest form, this dipole contribution model has only one free parameter, the perceptual noise for an element transition, which was estimated for various acoustic tone representations and chord arrangements. Results of two experiments, which were carried out independently in two different laboratories, are reported.  相似文献   
948.
949.
The incidence of secondary enuresis in 16 institutionalized conduct-disordered children was examined. In contrast to a control group of 16 noninstitutionalized conduct-disordered children, the former showed significantly more enuretic behaviour. Also, enuresis began within 6 mo. of the children's separation from their families, suggesting this problem is very likely related to the emotional trauma surrounding the change in living conditions. However, the small number of subjects limits further interpretation of the findings.  相似文献   
950.
An Extended Two-Way Euclidean Multidimensional Scaling (MDS) model which assumes both common and specific dimensions is described and contrasted with the standard (Two-Way) MDS model. In this Extended Two-Way Euclidean model then stimuli (or other objects) are assumed to be characterized by coordinates onR common dimensions. In addition each stimulus is assumed to have a dimension (or dimensions) specific to it alone. The overall distance between objecti and objectj then is defined as the square root of the ordinary squared Euclidean distance plus terms denoting the specificity of each object. The specificity,s j , can be thought of as the sum of squares of coordinates on those dimensions specific to objecti, all of which have nonzero coordinatesonly for objecti. (In practice, we may think of there being just one such specific dimension for each object, as this situation is mathematically indistinguishable from the case in which there are more than one.)We further assume that ij =F(d ij ) +e ij where ij is the proximity value (e.g., similarity or dissimilarity) of objectsi andj,d ij is the extended Euclidean distance defined above, whilee ij is an error term assumed i.i.d.N(0, 2).F is assumed either a linear function (in the metric case) or a monotone spline of specified form (in the quasi-nonmetric case). A numerical procedure alternating a modified Newton-Raphson algorithm with an algorithm for fitting an optimal monotone spline (or linear function) is used to secure maximum likelihood estimates of the paramstatistics) can be used to test hypotheses about the number of common dimensions, and/or the existence of specific (in addition toR common) dimensions.This approach is illustrated with applications to both artificial data and real data on judged similarity of nations.  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