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   19961篇
  免费   144篇
  国内免费   8篇
教育   15002篇
科学研究   1848篇
各国文化   164篇
体育   1018篇
综合类   3篇
文化理论   505篇
信息传播   1573篇
  2022年   56篇
  2021年   95篇
  2020年   154篇
  2019年   223篇
  2018年   2421篇
  2017年   2340篇
  2016年   1833篇
  2015年   351篇
  2014年   375篇
  2013年   1945篇
  2012年   450篇
  2011年   903篇
  2010年   1032篇
  2009年   619篇
  2008年   907篇
  2007年   1337篇
  2006年   301篇
  2005年   592篇
  2004年   596篇
  2003年   552篇
  2002年   294篇
  2001年   143篇
  2000年   139篇
  1999年   117篇
  1998年   115篇
  1997年   125篇
  1996年   117篇
  1995年   125篇
  1994年   119篇
  1993年   96篇
  1992年   114篇
  1991年   111篇
  1990年   102篇
  1989年   93篇
  1988年   84篇
  1987年   71篇
  1986年   67篇
  1985年   73篇
  1984年   60篇
  1983年   77篇
  1982年   73篇
  1981年   78篇
  1980年   82篇
  1979年   75篇
  1978年   54篇
  1977年   45篇
  1976年   55篇
  1975年   44篇
  1974年   40篇
  1971年   29篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
301.
This paper explores the assumptions underlying a commonplace school activity based on the mandated science curriculum: exploring the difference between natural and human made structures. Following a student's desire to use Dolly the Sheep as his example, a great array of contemporary and classical connections are explored.  相似文献   
302.
303.
304.
The evaluation of promisingness is central to knowledge building and knowledge creation but remains largely unexplored. As part of a design-based research program to support promisingness judgments, the present study implemented an intervention in a sixth grade science class, with the goal of exploring the potential of promisingness judgments to foster scientific understanding and epistemic beliefs. Aided by a Promising Ideas Tool and pedagogical supports designed for this intervention, students explored the concept of promisingness, judged the promisingness of their community ideas, and engaged in iterative cycles of idea refinement. Results indicated that students were capable of improving their understanding of promisingness and making promisingness judgments deemed sensible by domain experts. The conceptual understanding and epistemic beliefs displayed by students improved over the course of the intervention, and such improvement happened in tandem with students’ understanding of promisingness. The implications of this exploratory study and future research are discussed.  相似文献   
305.
306.
307.
308.
A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptually by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling. Based on this novel floating foundation, the hydrodynamic performance was investigated in the frequency domain and time domain by using the wave analysis software HydroD and DeepC from Det Norske Veritas. The frequency domain analysis was conducted to investigate the effects of the incident wave angle and water depth. The time-domain analysis was carried out to evaluate the response of the floating foundation under a selected operational condition. The hydrodynamic performances of this floating foundation with respect to time series and response spectra were also investigated in this study.  相似文献   
309.
1IntroductionIt is i mportant for the economic development of acountry to maintain the stabilization of exchange rate,so the intervention of exchange rate has become thetopic of the main concerns of the economic and math-ematical circles[1-5].To maintain the stabilization ofexchange rate,many countries use target zone re-gi mes,that is,the central banks intervene in the for-eign exchange market such that the exchange ratestays within the interval[a,b].There are fixed costand cost proportional …  相似文献   
310.
The National Policy on Education in Nigeria is an important document that had attractive plans for the Educational System of the country in general and, in particular, for persons with a disability. As the policy concerns the welfare and education of persons with a disability, its implementation has been fraught with the problem of lack of a legal document to regulate implementation activities. Basic to this problem, of course, are those of funding, limited definitions and policy objectives. This paper highlights these problems with brief discussions and concludes with suggestions for effective implementation.  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