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   12360篇
  免费   20篇
  国内免费   2篇
教育   9613篇
科学研究   1225篇
各国文化   23篇
体育   372篇
综合类   2篇
文化理论   385篇
信息传播   762篇
  2023年   2篇
  2022年   6篇
  2021年   9篇
  2020年   24篇
  2019年   22篇
  2018年   2194篇
  2017年   2104篇
  2016年   1585篇
  2015年   124篇
  2014年   142篇
  2013年   255篇
  2012年   240篇
  2011年   718篇
  2010年   858篇
  2009年   455篇
  2008年   667篇
  2007年   1164篇
  2006年   88篇
  2005年   407篇
  2004年   472篇
  2003年   375篇
  2002年   164篇
  2001年   22篇
  2000年   33篇
  1999年   7篇
  1998年   11篇
  1997年   30篇
  1996年   9篇
  1995年   12篇
  1994年   14篇
  1993年   14篇
  1992年   12篇
  1991年   19篇
  1990年   8篇
  1989年   10篇
  1988年   11篇
  1987年   11篇
  1986年   4篇
  1985年   7篇
  1984年   6篇
  1983年   9篇
  1982年   3篇
  1981年   5篇
  1980年   8篇
  1979年   8篇
  1978年   5篇
  1977年   10篇
  1976年   9篇
  1975年   5篇
  1945年   1篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
181.
Whole system improvement—where the vast majority of schools improve—is difficult to achieve. Some jurisdictions use what turns out to be ‘wrong’ policy drivers like testing and evaluation. Rather, success turns out to depend on changing the culture of schools and their relationship to the infrastructure of policies and regulation. I examined the six cases studies in the light of whole system change criteria. Two of the case studies, South Africa and India, represent limited but useful examples in that they focus on basic skills like literacy. A second set of two studies, Escuela Nueva and LCP in Mexico, represent strong examples of how bottom up strategies can spread to significant levels. The final two, Long Beach in the US and Ontario, are strong examples of how deep change can be accomplished by focusing on a few core priorities and then building a culture over a number of years to support and sustain the changes. The paper then draws conclusions about the conditions that will be required for large scale change to occur.  相似文献   
182.
The co-effect of transmitted power fluctuation and system nonlinearity produce deviations in scatterometer measurement results . An internal calibration method to deal with this problem is proposed. The method can result in more precise scatterometric measurements in a wide range. The basic principle of the method is combining real-transmitted-power detection with the calibration of system nonlinearity. A practical scheme to implement the method is also presented, which is developed based on a special designed mechanism of a microwave radiometer-scatterometer combined system.  相似文献   
183.
Visual cues have an important role in food preference for both rats and humans. Here, we aim to isolate the effects of numerosity, density, and surface area on food preference and running speed in rats, by using a forced-choice maze paradigm. In Experiment 1, rats preferred and ran faster for a group of multiple smaller pellets rather than a single large pellet, corroborating previous research (Capaldi, Miller, & Alptekin Journal of Experimental Psychology: Animal Behavior Processes, 15(1), 75–80, 1989). Further experiments tested the prevailing hypothesis that multiple food pieces are more reinforcing because they occupy a larger surface area. Experiment 2 controlled for numerosity by utilizing a continuous food: mashed potatoes flattened to cover a larger surface area or rounded into a ball. The rats preferred and ran faster for the flattened potatoes, suggesting surface area plays a role in quantity estimations. Finally, in Experiment 3, rats displayed no preference or difference in running speed between a group of scattered and clustered pellets when number of pellets were kept constant. Taken together, these results suggest that density has an important role in food perception—that is, the rewarding effect of higher numerosity or larger surface area is removed when the food does not fill out the entire space. Alternative explanations and implications for human diet are discussed.  相似文献   
184.
This study employed content analysis to examine 3 popular middle-grades mathematics curricula in the USA on the support they provide for teachers to implement concepts associated with variables in school mathematics. The results indicate that each of the 3 curricula provides some type of support for teachers, but in a varied amount and quality. More specifically, whereas the University of Chicago School Mathematics Project (UCSMP) curriculum provides support for teachers on several aspects of using variables in school mathematics, the support found in the Connected Mathematics 2 and the Math Connects curricula focused mainly on one conception of variables—namely, the use of variables as quantity that varies in the Connected Mathematics 2 curriculum and the use of variables as specific unknowns in the Math Connects curriculum. Overall, the UCSMP curriculum provides the most support for teachers, followed by the Connected Mathematics 2 curriculum, with the Math Connects curriculum recording the least support for teachers to enact variable concepts. It is worth pointing out that, although the 3 curricula collectively provide guidance for teachers to implement variable ideas within meaningful real-world contexts, the supports identified in the respective curriculum were not sufficient in addressing all of the areas that are essential for teaching the many concepts associated with variables in school mathematics effectively. Recommendations for curriculum developers and for international researchers with interest in the roles of variables in school mathematics are provided.  相似文献   
185.
Propagation stability of non-paraxial beam in nonlinear Kerr media is investigated with a linear stability method.Both theoretical analysis and numerical simulation show that modulation instability(MI) gain spectrum has three different distribution features determined by the times of incident power P0 and the non-paraxial parameter a. Furthermore,the corresponding criterion is put forward to distinguish the three different distributions.  相似文献   
186.
187.
188.
This paper addresses the effect of leakage on the natural frequencies of a large amplitude vibrating panel backed by a cavity, which has not been considered in many other related studies. The structural-acoustic governing equations are employed to study this nonlinear problem. An elliptical integral method, which was recently developed for the nonlinear panel cavity problem, is introduced here to solve for the structural-acoustics responses. The present results agree reasonably well with those obtained from the classical harmonic balance method. Modal convergences of the nonlinear solutions are performed to verify the proposed method. The effects of vibration amplitude and leakage size are studied and discussed. It is found that (1) the edge leakages in a panel cavity system significantly affect the natural frequency properties, and (2) the edge leakages induce a low frequency acoustic resonance.  相似文献   
189.
Genetic determinism can be described as the attribution of the formation of traits to genes, where genes are ascribed more causal power than what scientific consensus suggests. Belief in genetic determinism is an educational problem because it contradicts scientific knowledge, and is a societal problem because it has the potential to foster intolerant attitudes such as racism and prejudice against sexual orientation. In this article, we begin by investigating the very nature of belief in genetic determinism. Then, we investigate whether knowledge of genetics and genomics is associated with beliefs in genetic determinism. Finally, we explore the extent to which social factors such as gender, education, and religiosity are associated with genetic determinism. Methodologically, we gathered and analyzed data on beliefs in genetic determinism, knowledge of genetics and genomics, and social variables using the “Public Understanding and Attitudes towards Genetics and Genomics” (PUGGS) instrument. Our analyses of PUGGS responses from a sample of Brazilian university freshmen undergraduates indicated that (1) belief in genetic determinism was best characterized as a construct built up by two dimensions or belief systems: beliefs concerning social traits and beliefs concerning biological traits; (2) levels of belief in genetic determination of social traits were low, which contradicts prior work; (3) associations between knowledge of genetics and genomics and levels of belief in genetic determinism were low; and (4) social factors such as age and religiosity had stronger associations with beliefs in genetic determinism than knowledge. Although our study design precludes causal inferences, our results raise questions about whether enhancing genetic literacy will decrease or prevent beliefs in genetic determinism.  相似文献   
190.
In this paper, we discuss methodological issues that emerged as we worked through a small empirical research project, ‘Engaging Aboriginal students in education through community empowerment’. Recent national policy statements (see, for example, MCEETYA 2000, NBEET 1995) argue the importance of education/research that keeps the locus of control within the Aboriginal community as a means to further the goal of self-determination and improve educational outcomes. In keeping with these recommendations, our project aimed to challenge assimilationist frameworks and sought to ‘empower’ members of the local Aboriginal community through participation in the project.  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