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   9341篇
  免费   147篇
  国内免费   217篇
  2018年   38篇
  2017年   29篇
  2016年   28篇
  2015年   43篇
  2014年   43篇
  2013年   46篇
  2012年   752篇
  2011年   841篇
  2010年   227篇
  2009年   119篇
  2008年   654篇
  2007年   686篇
  2006年   587篇
  2005年   526篇
  2004年   468篇
  2003年   437篇
  2002年   391篇
  2001年   277篇
  2000年   297篇
  1999年   168篇
  1998年   58篇
  1997年   34篇
  1996年   55篇
  1995年   43篇
  1994年   93篇
  1993年   107篇
  1992年   104篇
  1991年   119篇
  1990年   120篇
  1989年   128篇
  1988年   144篇
  1987年   145篇
  1986年   113篇
  1985年   136篇
  1984年   115篇
  1983年   150篇
  1982年   100篇
  1981年   109篇
  1980年   81篇
  1979年   84篇
  1978年   73篇
  1966年   50篇
  1965年   144篇
  1964年   112篇
  1963年   134篇
  1962年   57篇
  1958年   96篇
  1957年   84篇
  1956年   47篇
  1953年   16篇
排序方式: 共有9705条查询结果,搜索用时 31 毫秒
971.
Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we reinforced the least frequent saccadic amplitudes to increase variability, and then reinforced the central part of the amplitude distributions to reduce variability. The target was placed at a constant distance from the fovea after the saccade to maintain the postsaccadic visual signal constant and an auditory reinforcement was delivered depending on saccadic amplitude. The second experiment tested the effects of the contingency. We reinforced high levels of variability in 4 participants, whereas 4 other participants were assigned to a yoked control group. On average, saccadic amplitude standard deviations were doubled while the medians remained mostly unchanged in the experimental participants in both experiments, and variability returned to baseline level when low variability was reinforced. In the control group no consistent changes in amplitude distributions were observed. These results, showing that variability can be reinforced, challenge the idea of a stochastic neural noise. We instead propose that selection processes constrain saccadic amplitude distributions.  相似文献   
972.
The present study focused on the motivational predictors of coping with academic examination through the test of the contribution of self-determination for academic studies and achievement goals. Coping strategies, academic motivation and achievement goals were assessed among 199 undergraduate students. Regression analysis revealed that problem-focused coping is positively predicted by identified regulation and negatively by amotivation, whereas emotion-focused coping is positively predicted by introjected regulation and amotivation. Mastery approach goals contributed positively to problem-focused coping. Identified regulation and mastery approach goals made a unique positive contribution to problem-focused coping, and amotivation was negatively related. Students' coping actions may vary according to both the reasons why they engage in academic studies and the goals they pursue in this setting.  相似文献   
973.
Two experiments examined the role of numerical distance in updating numerical information in working memory. In the first experiment, participants had to memorize a new number only when it was smaller than a previously memorized number. In the second experiment, updating was based on an external signal, which removed the need to perform any numerical comparison. In both experiments, distance between the memorized number and the new one was manipulated. The results showed that smaller distances between the new and the old information led to shorter updating times. This graded facilitation suggests that the process by which information is substituted in the focus of attention involves maintaining the shared features between the new and the old number activated and selecting other new features to be activated. Thus, the updating cost may be related to amount of new features to be activated in the focus of attention.  相似文献   
974.
There is a knowledge gap concerning how well community-based teams fare in implementing evidence-based interventions (EBIs) over many years, a gap that is important to fill because sustained high quality EBI implementation is essential to public health impact. The current study addresses this gap by evaluating data from PROSPER, a community-university intervention partnership model, in the context of a randomized-control trial of 28 communities. Specifically, it examines community teams' sustainability of implementation quality on a range of measures, for both family-focused and school-based EBIs. Average adherence ratings approached 90% for family-focused and school-based EBIs, across as many as 6 implementation cohorts. Additional indicators of implementation quality similarly showed consistently positive results. Correlations of the implementation quality outcomes with a number of characteristics of community teams and intervention leaders were calculated to explore their potential relevance to sustained implementation quality. Though several relationships attained statistical significance at particular points in time, none were stable across cohorts. The role of PROSPER's continuous, proactive technical assistance in producing the positive results is discussed.  相似文献   
975.
976.
977.
The current study examined the longitudinal stability and invariance of psychopathic traits in a large community sample of male twins from ages 17 to 23. Participants were assessed across 6 years to gauge the stability and measurement invariance of the Minnesota Temperament Inventory (MTI), a Cleckley-based measure of psychopathic personality traits, and how family functioning and externalizing behavior were linked to these traits. A latent variable approach was used to model the structure of the MTI and provide a statistical test of measurement invariance across time. The results revealed support for invariance and moderate to strong stability of the MTI factors, which showed significant associations with the external correlates in late adolescence but not early adulthood.  相似文献   
978.

Objective

The purpose of this article is to introduce a new assessment designed to measure the orofacial abilities of children who stutter (CWS), the Movement, Articulation, Mandibular and Sensory Awareness (MAMS) Orofacial Assessment. The new instrument was developed and validated to measure orofacial abilities in a comprehensive manner.

Design

A group of 43 CWS (mean age 13.10 years, S.D. 2.10 years) and a control group of 32 fluent children (mean age 13.4 years, S.D. 2.6 years) were tested with the new tool. It was hypothesized, that (a) the MAMS is a reliable and valid instrument to measure orofacial abilities in CWS, (b) fluent children have better orofacial abilities than CWS and (c) that the therapy outcome of CWS depend on their orofacial abilities.

Results

The MAMS Orofacial Assessment proved to be a valid and reliable instrument to assess orofacial abilities. Compared with their fluent peers, CWS had significantly worse orofacial abilities. CWS with better orofacial abilities had a better prognosis for therapy outcome.

Conclusions

The new instrument is a reliable and valid tool to measure orofacial abilities and MAMS distinguishes CWS and controls. Orofacial abilities are one set of factors that influence therapy outcome for CWS.Educational objectives: The reader will get an overview over of the literature on orofacial abilities in people who stutter and will learn about and be able to (1) describe different characteristics of orofacial abilities, (2) use the MAMS Orofacial Assessment in the diagnostic process for CWS and for research purposes, and (3) interpret the results of the MAMS to use them for therapy planning.  相似文献   
979.
The role of physical and relational aggression in adolescents' friendship selection was examined in a longitudinal sample of 274 Chilean students from 5th and 6th grade followed over 1 year. Longitudinal social network modeling (SIENA) was used to study selection processes for aggression while influence processes were controlled for. Furthermore, the effects of network characteristics (i.e., reciprocity and transitivity), gender, and social status on friendship selection were examined. The starting assumption of this study was that selection effects based on aggression might have been overestimated in previous research as a result of failing to consider influence processes and alternative characteristics that steer friendship formation. The results show that selection effects of both physical and relational aggression disappeared when network effects, gender, and social status were taken into account. Particularly gender and perceived popularity appeared to be far more important determinants of friendship selection over time than aggression. Moreover, a peer influence effect was only found for relational aggression, and not for physical aggression. These findings suggest that similarity in aggression among befriended adolescents can be considered to be mainly a by-product rather than a leading dimension in friendship selection.  相似文献   
980.
Our representation of peripersonal space does not always accurately reflect the physical world. An example of this is pseudoneglect, a phenomenon in which neurologically normal individuals bisect to the left of the veridical midpoint, reflecting an overrepresentation of the left portion of space compared with the right one. Consistent biases have also been observed in the vertical and radial planes. It is an open question whether these biases depend on normal visual experience for their occurrence. Here we systematically investigated this issue by testing blindfolded sighted and early blind individuals in a haptic line bisection task. Critically, we found a robust leftward bias in all participants. In the vertical and radial planes, sighted participants showed a consistent downward and proximal bias. Conversely, the directional bias in blind participants was dependent on the final movement direction; thus, there was no general bias in either direction. These findings are discussed in terms of different reference frames adopted by sighted and blind participants when encoding space.  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