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   2454篇
  免费   44篇
  国内免费   3篇
教育   1753篇
科学研究   136篇
各国文化   34篇
体育   313篇
综合类   2篇
文化理论   24篇
信息传播   239篇
  2023年   15篇
  2022年   11篇
  2021年   26篇
  2020年   54篇
  2019年   88篇
  2018年   94篇
  2017年   94篇
  2016年   110篇
  2015年   66篇
  2014年   85篇
  2013年   609篇
  2012年   59篇
  2011年   84篇
  2010年   66篇
  2009年   53篇
  2008年   64篇
  2007年   83篇
  2006年   48篇
  2005年   43篇
  2004年   43篇
  2003年   36篇
  2002年   44篇
  2001年   30篇
  2000年   41篇
  1999年   31篇
  1998年   21篇
  1997年   17篇
  1996年   21篇
  1995年   15篇
  1994年   26篇
  1993年   25篇
  1992年   20篇
  1991年   19篇
  1990年   15篇
  1989年   18篇
  1988年   18篇
  1987年   16篇
  1986年   24篇
  1985年   18篇
  1984年   16篇
  1983年   20篇
  1982年   25篇
  1981年   19篇
  1980年   13篇
  1979年   14篇
  1978年   11篇
  1977年   13篇
  1976年   10篇
  1975年   15篇
  1973年   12篇
排序方式: 共有2501条查询结果,搜索用时 15 毫秒
101.
Within the UK, the "Long Term Athlete Development" (LTAD) model has been proposed by a variety of national governing bodies to offer a first step to considering the approach to talent development. The model, which is primarily a physiological perspective, presents an advancement of understanding of developing athletic potential alongside biological growth. It focuses on training to optimize performance longitudinally, and considers sensitive developmental periods known as "windows of opportunity". However, it appears that there are a number of problems with this theoretical model that are not necessarily transparent to coaches. Principally, the model is only one-dimensional, there is a lack of empirical evidence upon which the model is based, and interpretations of the model are restricted because the data on which it is based rely on questionable assumptions and erroneous methodologies. Fundamentally, this is a generic model rather than an individualized plan for athletes. It is crucial that the LTAD model is seen as a "work in progress" and the challenge, particularly for paediatric exercise scientists, is to question, test, and revise the model. It is unlikely that this can be accomplished using classical experimental research methodology but this should not deter practitioners from acquiring valid and reliable evidence.  相似文献   
102.
Most document clustering algorithms operate in a high dimensional bag-of-words space. The inherent presence of noise in such representation obviously degrades the performance of most of these approaches. In this paper we investigate an unsupervised dimensionality reduction technique for document clustering. This technique is based upon the assumption that terms co-occurring in the same context with the same frequencies are semantically related. On the basis of this assumption we first find term clusters using a classification version of the EM algorithm. Documents are then represented in the space of these term clusters and a multinomial mixture model (MM) is used to build document clusters. We empirically show on four document collections, Reuters-21578, Reuters RCV2-French, 20Newsgroups and WebKB, that this new text representation noticeably increases the performance of the MM model. By relating the proposed approach to the Probabilistic Latent Semantic Analysis (PLSA) model we further propose an extension of the latter in which an extra latent variable allows the model to co-cluster documents and terms simultaneously. We show on these four datasets that the proposed extended version of the PLSA model produces statistically significant improvements with respect to two clustering measures over all variants of the original PLSA and the MM models.  相似文献   
103.
The methodology of protecting the European stained glass windows against environmental risk (e.g. meteorological factors, air pollution, microorganisms) by means of an external glazing is not new. In spite of many scientific studies carried out in the last 20 years, some questions were still up for discussion. The European VIDRIO (2002–2005) project gave an answer to these questions. The research carried out by the different project partners established a new multidisciplinary approach aimed at evaluating the efficiency of the protective glazing systems and their effects on stained glass windows conservation, and finally at assessing the most appropriate strategy to preserve stained glass windows. Scientific results showed that the so-called isothermal glazing (i.e. ventilation by the air coming from the inside of the building) protected efficiently the ancient stained glass window from environmental attack (i.e. rain, pollutants, condensation, thermal shocks) with very limited secondary effects. The scientific research highlighted that its efficiency was strongly related to the technical design of the protective system. In particular, the ventilation and the size of the interspace had to be carefully considered. The research developed within the VIDRIO project was turned into general recommendations to the owners and practitioners on the best practice for the stained glass windows future conservation.  相似文献   
104.
In the late nineteenth century, issues such as professionalization, the advancement of women, and the appropriate training of teachers faced our field. The Boston Normal School of Gymnastics (BNSG) was instrumental in addressing these issues, and perhaps addressed most thoroughly, the training of teachers. This paper examines the legacy of the BNSG on today's physical education teacher preparation (PETE) programs. Many have documented the infloence of the BNSG as one of the first successful physical education teacher training institutions. However, what has not been examined are the particular philosophies of the administrators and teachers at the BNSG that still persevere in colleges and universities today. The BNSG was instrumental in the professionalization of the field and in the advancement of women in physical education. The argument is made that perhaps the BNSG's greatest contribution was in the development of many philosophies and basic pedagogical concepts such as combining theory and practice, teaching with progressions, and using experts to train future teachers, and these philosophies and concepts that guide today's PETE programs were the same used in the BNSG over a century ago.  相似文献   
105.
Clinical discourses from the domains of medicine and psychology exert a powerful influence on theory and practice in special education. These discourses first define disability as ‘an individual human condition’ and locate ‘the problem’ in the physiological and psychological characteristics of the individual. Second, they privilege the role of experts and exclude the perspectives of disabled people themselves. In spite of considerable criticism, psycho-medical definitions of and responses to disability have been incorporated into educational legislation in Ireland and continue to dominate policy development in special education. The real danger of failing to address these deep structures in special education is that exclusion and marginalization will be reproduced even in well-intentioned and well-supported programmes.  相似文献   
106.
107.
108.
根据制造产业集群知识资源的特点,结合集群环境下知识资源管理的优势,从知识资源管理流程入手分析研究制造产业集群知识资源管理机制,主要包括:知识资源的整合机制、显性化机制、共享机制、创新机制、学习与流动机制、激励机制和保障机制,并提出集群协同创新服务平台知识资源管理体系架构。  相似文献   
109.
Pigeons were trained on a discrete-trial delayed reinforcement procedure with respect to one response key that was periodically illuminated. In some conditions, a second response key, or a tone, both previously paired with reinforcement, was interpolated in the delay-of-reinforcement interval. In comparison to a control condition with neither stimulus in the delay interval, the interpolated stimulus attenuated (blocked) the amount of responding that was maintained by the delayed reinforcement contingency. The degree of blocking was unaffected by whether the interpolated stimulus was the tone or keylight, in spite of the fact that the keylight evoked responding and the tone did not. A second study showed that the blocking effects involved the response-reinforcer association in that blocking occurred when the delayed reinforcement was response-dependent but did not occur when reinforcement was response-independent. The results thus show that response-reinforcer associations are affected by informational variables in the same manner as has been shown for stimulus-reinforcer associations. They also demonstrate that preexisting stimulus-reinforcer associations can block response-reinforcer associations, thus suggesting that both types of association depend upon the same associative process.  相似文献   
110.
On a kayak ergometer, an accurate simulation of the athlete-paddle-kayak system kinematics is essential for analysing the relationship between technique and performance. The purpose of this study was to establish a strong relationship between performances on flatwater and performances on an ergometer by means of propulsive force measurement and drag models. Two trials were performed by 12 kayakers in which they were first timed over 250 m of flatwater kayaking (the reference test) and were then asked to perform a trial of the same duration on the ergometer with the same perceived physical exertion. Three techniques for measuring propulsive force and three drag models generated nine combinations, which were all evaluated for their ability to estimate kayak velocity. For each combination, the distance covered by the athlete on the ergometer was simulated. A kayakers’ ergometer ranking was based on the average velocity in the ergometer trial. Both distance and ranking were compared to the on-water results. The simulation with the best combination of force measurement and drag model gave an accurate estimate of distance (253 ± 10.5 vs. 250 m) and ranking compared to the reference test.  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