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   44782篇
  免费   876篇
  国内免费   12篇
  2020年   244篇
  2019年   260篇
  2018年   3793篇
  2017年   3148篇
  2016年   2645篇
  2015年   470篇
  2014年   455篇
  2013年   2012篇
  2012年   1276篇
  2011年   3129篇
  2010年   2946篇
  2009年   1900篇
  2008年   2332篇
  2007年   2797篇
  2006年   618篇
  2005年   743篇
  2004年   697篇
  2003年   592篇
  2002年   573篇
  2001年   801篇
  2000年   842篇
  1999年   599篇
  1998年   312篇
  1997年   264篇
  1996年   239篇
  1993年   231篇
  1992年   480篇
  1991年   431篇
  1990年   481篇
  1989年   432篇
  1988年   423篇
  1987年   412篇
  1986年   418篇
  1985年   443篇
  1984年   352篇
  1983年   313篇
  1982年   255篇
  1979年   403篇
  1978年   290篇
  1977年   267篇
  1975年   349篇
  1974年   389篇
  1973年   359篇
  1972年   339篇
  1971年   293篇
  1970年   270篇
  1969年   328篇
  1968年   367篇
  1967年   327篇
  1966年   329篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
982.
Orienting the finger opposition space during prehension movements   总被引:3,自引:0,他引:3  
Two experiments are reported that examined the act of prehension when subjects were asked to grasp with their thumb and index finger pads an elongated object resting horizontally on a surface and placed at different orientations with respect to the subject. In Experiment 1, the pad opposition preferences were determined for the six angles of orientation examined. For angles of 90 degrees (object parallel to frontal plane) or less, no rotation of the wrist (pronation) was used; for angles 110 degrees or greater, pronation was systematically employed to reorient the finger opposition space. Only one angle, 100 degrees , produced any evidence of ambiguity in how to grasp the object: Approximately 60% of these grasps involved pronation and 40% did not. Using the foregoing grasp preference data, in Experiment 2 we examined the kinematics of the wrist and elbow trajectories during prehension movements directed at an object in different orientations. Movement time, time to peak acceleration, velocity, and deceleration were measured. No kinematic differences were observed when the object orientation either required (110 degrees ) or did not require (80 degrees ) a pronation. By contrast, if the orientation was changed at the onset of the movement, such that an unpredicted pronation had to be introduced to achieve the grasp, kinematics were affected: Movement time was increased, and the time devoted to deceleration was lengthened. These data are interpreted as evidence that when natural prehension occurs, pronation can be included in the motor plan without affecting the movement kinematics. When constraints are imposed on the movement execution as a consequence of a perturbation, however, the introduction of a pronation component requires kinematic rearrangement.  相似文献   
983.
Subjects (N = 8) performed a timed response task in which they attempted to synchronize an impulsive foot-press response with the last in a series of four regularly spaced tones. In Experiment 1, the response was countermanded on one third of the trials (stop trials) by a stop signal that appeared at a predetermined delay after the third tone. No stop signal appeared on the remaining trials (go trials). All subjects showed a systematic transition from withholding the response on stop trials in which the stop signal appeared shortly after the third tone to executing the response on trials in which a single stop signal delay had been chosen so that a response would be made on about 50% of the stop trials. We elicited Hoffmann (H) reflexes from the soleus muscle on all trials to determine whether the reflexes were augmented on occasions on which a response was prepared but withheld. Mean H-reflex amplitudes on go trials and on stop trials on which the response was executed were similar and showed a marked augmentation beginning about 250 ms before response onset; mean H-reflex amplitudes on stop trials on which the response was withheld showed less pronounced augmentation. Inspection of individual H-reflex amplitudes revealed that on stop trials on which the response was withheld the reflexes could be augmented to the same extent as on trials on which the response was executed. This dissociation of H-reflex augmentation and response execution shows that H-reflex augmentation reflects a controlled response process. Ballistic response processes therefore must be limited to a brief duration.  相似文献   
984.
Two experiments considered the behavior of subjects who cross gaps in a pathway without benefit of vision. The first experiment contrasted visually and nonvisually guided locomotion, finding a significantly greater number of refusals under nonvisual guidance but no loss of appropriate modulation of step components to the salient dimensions of the actor and layout. Different components of crossing were modified under guidance of different sensory systems; the lengths of the crossing and support spans were primarily altered under nonvisual guidance, and the distance of the support foot to the near edge of the gap was the component of preference under visual guidance. In the second experiment, subjects crossed nonvisually, using probes that varied in length and moment of inertia. The adaptability of the step components to actor and layout dimensions was unchanged, but there was no effect of these mechanical manipulations on the components of crossing identified in Experiment 1.  相似文献   
985.
Exchange delays and impulsive choice in adult humans.   总被引:4,自引:3,他引:1       下载免费PDF全文
Choice responding by adult humans in a discrete-trial task was examined as a function of conditions that manipulated either the delay to point delivery or the delay between points and their exchange for money. In point-delay conditions, subjects chose between an "impulsive" alternative that provided a small amount of points immediately and a "self-control" alternative that provided a larger amount of points delayed by 15, 30, or 60 s. Points were exchanged for money immediately following the session. Subjects preferred the self-control alternative. In exchange-delay conditions, subjects chose between a small amount of points exchangeable for money immediately following the session and a larger amount of points exchangeable for money after 1 day, 3 weeks, or 6 weeks. A self-control preference observed for all subjects in the 1-day exchange-delay condition reversed to exclusive impulsive preference for 4 of the 6 subjects when choice conditions involved exchange delays of 3 or 6 weeks. These results show that human choice is sensitive to the manipulation of exchange delays and that impulsive preference can be obtained with exchange delays on the order of weeks.  相似文献   
986.
Socratic method and intuition are two ways of knowing commonly thought as opposed. The author shows how both ways of knowing can be linked in an education that has philosophy as its armature.  相似文献   
987.
Acceptance and Commitment Therapy (ACT) is a behavior-analytically-based psychotherapy approach that attempts to undermine emotional avoidance and increase the capacity for behavior change. An overview of this approach is given, followed by several specific examples of the techniques used within ACT. In each instance the behavioral rationale of these techniques is described. A contemporary view of verbal relations provides the basis for new approaches to adult outpatient psychotherapy.  相似文献   
988.
The authors review four new instruments designed to assess multicultural counseling competence in trainees and practicing professionals. The Cross-Cultural Counseling Inventory—Revised (CCCI-R), the Multicultural Counseling Awareness Scale—Form B (MCAS:B), the Multicultural Counseling Inventory (MCI), and the Multicultural Awareness-Knowledge-and Skills Survey (MAKSS) were each critically reviewed in terms of item development, psychometric properties, and pragmatic utility. Specific research suggestions for continued empirical validation on the instruments are posited, and strong cautions regarding their current use in training are leveled.  相似文献   
989.
This article focuses on the unique counselling needs of foreign students as reflected from a review of the literature. As more and more students from developing countries opt to further their education in the West, knowledge about counselling foreign students is of increasing interest. Distinctive aspects of foreign student clients and the typical problems faced by them are described. The issues which need to be addressed and the competencies which need to be developed in order to effectively counsel foreign students are discussed. Finally, specific strategies for counselling foreign students are suggested in the context of general guidelines for cross-cultural counselling.  相似文献   
990.
Research in several disciplines reveals large individual differences in orientations to romantic love, yet the origins of the differences have been unclear In this first behavior genetic study of romantic love, biometric model fitting reveals that in contrast to other personality and attitude domains, where genetic factors account for approximately 50% of the reliable variance and shared environment has little effect, individual differences in romantic love are due almost exclusively to environment Moreover, the common family environment plays a sizable role in determining love styles, a finding compatible with theories stressing the importance of family interactions in personality development  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