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   2668篇
  免费   204篇
  国内免费   320篇
  3192篇
  2024年   11篇
  2023年   49篇
  2022年   50篇
  2021年   90篇
  2020年   160篇
  2019年   141篇
  2018年   149篇
  2017年   144篇
  2016年   149篇
  2015年   110篇
  2014年   134篇
  2013年   403篇
  2012年   102篇
  2011年   126篇
  2010年   72篇
  2009年   124篇
  2008年   98篇
  2007年   117篇
  2006年   99篇
  2005年   110篇
  2004年   104篇
  2003年   91篇
  2002年   72篇
  2001年   68篇
  2000年   58篇
  1999年   36篇
  1998年   35篇
  1997年   33篇
  1996年   23篇
  1995年   38篇
  1994年   22篇
  1993年   10篇
  1992年   10篇
  1991年   12篇
  1990年   8篇
  1989年   12篇
  1988年   9篇
  1987年   11篇
  1986年   6篇
  1985年   11篇
  1984年   15篇
  1983年   8篇
  1982年   13篇
  1981年   8篇
  1980年   7篇
  1979年   12篇
  1977年   4篇
  1976年   3篇
  1975年   7篇
  1974年   4篇
排序方式: 共有3192条查询结果,搜索用时 0 毫秒
991.
992.
993.

The diffusion kinetics in a concentrated fcc alloy are described by means of divacancies. The model chosen is the random alloy model with bound divacancies. We show that for the fcc structure the Manning formalism developed originally for monovacancies can be used intact to describe diffusion via divacancies. Monte Carlo simulation results for both tracer and collective correlation factors are in good agreement with the results of the formalism for a wide range of the component atom exchange frequencies with the divacancy except for the slower-moving component.  相似文献   
994.

Time-of-flight inelastic neutron scattering spectra were measured on cerium metal at temperatures near the fcc (gamma)-to-bcc (delta) transition temperature. Phonon density-of-states (DOS) curves were extracted from data acquired over a wide range of momentum transfers. A large softening of the phonon DOS was found in going from gamma-cerium to delta-cerium, and this accounts for an increase in vibrational entropy of (0.71 +/- 0.05)k B/atom. To be consistent with the latent heat of the gamma-delta transition, this increase in vibrational entropy must be accompanied by a large decrease in electronic entropy. The results not only confirm the recent discovery of a significant electronic contribution to the gamma-delta transition but also suggest that it may be twice that previously reported.  相似文献   
995.
996.
Genetic and environmental correlation matrices among 7 personality scales were estimated, using samples of adult and young adult twins from Australia (2081 and 1178 pairs, respectively). A general factor of personality and two supplemental factors were obtained in each. The supplemental factors were tentatively identified as Social conformity and Other-dependence. Factors from the genetic and environmental correlations replicated well across samples, and they were similar in both the genetic and environmental covariation. It was concluded that the structure of personality is inherent in the evolved phenotype, and is not the immediate consequence of either genetic or environmental organizing factors.  相似文献   
997.
This article suggests that we are in the midst of a profound dimensional shift in our rational capacity to process reality, and seeks to articulate the implications of this evolutionary shift to global reason for our scientific enterprise. As we enter the 21st century it is unmistakably clear that we are in the midst of an unprecedented shift in the human condition—a global renaissance that affects every aspect of our cultural lives, our self-understanding, and, of course, our rational enterprise. This evolutionary transformation, when seen through the expanded global lens, has been emerging through the ages on a global scale. In this brief reflection I suggest that this advance in our technology of mind is of an order of magnitude that is so radical and comprehensive that the very concept of a person, of what it means to be human, of our encounter with Reality and all our hermeneutical arts, including the sciences, are likewise taken to a higher global dimension. I suggest that the diverse voices included in this special edition are best situated in the context of this global awakening of reason, scientific knowing, and the holistic worldview.  相似文献   
998.
Ruth     
《Women & Therapy》2013,36(1):7-11
No abstract available for this article.  相似文献   
999.
In this study we quantify for the first time electrophysiological components associated with incorporating long-term semantic knowledge with visuo-spatial information using two variants of a traditional matrix patterns task. Results indicated that the matrix task with greater semantic content was associated with enhanced accuracy and RTs in a change-detection paradigm; this was also associated with increased P300 and N400 components as well as a sustained negative slow wave (NSW). In contrast, processing of the low semantic stimuli was associated with an increased N200 and a reduction in the P300. These findings suggest that semantic content can aid in reducing early visual processing of information and subsequent memory load by unitizing complex patterns into familiar forms. The N400/NSW may be associated with the requirements for maintaining visuo-spatial information about semantic forms such as orientation and relative location. Evidence for individual differences in semantic elaboration strategies used by participants is also discussed.  相似文献   
1000.
Humans are extremely good at detecting anomalies in sensory input. For example, while listening to a piece of Western-style music, an anomalous key change or an out-of-key pitch is readily apparent, even to the non-musician. In this paper we investigate differences between musical experts and non-experts during musical anomaly detection. Specifically, we analyzed the electroencephalograms (EEG) of five expert cello players and five non-musicians while they listened to excerpts of J.S. Bach’s Prelude from Cello Suite No. 1. All subjects were familiar with the piece, though experts also had extensive experience playing the piece. Subjects were told that anomalous musical events (AMEs) could occur at random within the excerpts of the piece and were told to report the number of AMEs after each excerpt. Furthermore, subjects were instructed to remain still while listening to the excerpts and their lack of movement was verified via visual and EEG monitoring. Experts had significantly better behavioral performance (i.e. correctly reporting AME counts) than non-experts, though both groups had mean accuracies greater than 80%. These group differences were also reflected in the EEG correlates of key-change detection post-stimulus, with experts showing more significant, greater magnitude, longer periods of, and earlier peaks in condition-discriminating EEG activity than novices. Using the timing of the maximum discriminating neural correlates, we performed source reconstruction and compared significant differences between cellists and non-musicians. We found significant differences that included a slightly right lateralized motor and frontal source distribution. The right lateralized motor activation is consistent with the cortical representation of the left hand – i.e. the hand a cellist would use, while playing, to generate the anomalous key-changes. In general, these results suggest that sensory anomalies detected by experts may in fact be partially a result of an embodied cognition, with a model of the action for generating the anomaly playing a role in its detection.  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