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   9077篇
  免费   80篇
  国内免费   8篇
教育   6247篇
科学研究   1135篇
各国文化   56篇
体育   627篇
综合类   3篇
文化理论   53篇
信息传播   1044篇
  2022年   54篇
  2021年   111篇
  2020年   144篇
  2019年   190篇
  2018年   312篇
  2017年   292篇
  2016年   284篇
  2015年   168篇
  2014年   279篇
  2013年   1540篇
  2012年   213篇
  2011年   248篇
  2010年   215篇
  2009年   192篇
  2008年   239篇
  2007年   204篇
  2006年   177篇
  2005年   166篇
  2004年   183篇
  2003年   139篇
  2002年   141篇
  2001年   201篇
  2000年   209篇
  1999年   193篇
  1998年   102篇
  1997年   133篇
  1996年   113篇
  1995年   78篇
  1994年   99篇
  1993年   71篇
  1992年   169篇
  1991年   128篇
  1990年   124篇
  1989年   147篇
  1988年   130篇
  1987年   106篇
  1986年   114篇
  1985年   111篇
  1984年   83篇
  1983年   96篇
  1982年   62篇
  1981年   75篇
  1980年   66篇
  1979年   107篇
  1978年   70篇
  1977年   66篇
  1976年   57篇
  1975年   53篇
  1974年   63篇
  1973年   63篇
排序方式: 共有9165条查询结果,搜索用时 0 毫秒
81.
The study was designed to evaluate the hepatoprotective activity of ethanolic extract of Bacopa monnieri in acute experimental liver injury induced by Nitrobenzene in rats. The extract at the dose of 200 mg/kg body weight was administered orally once every day for 10 days. The increased serum marker enzymes, Aspartate transaminase, Alanine transaminase and alkaline phosphatase were restored towards normalization significantly by the extract. Significant increase in SOD, CAT and GPx was observed in extract treated liver injured experimental rats. Histopathological examination of the liver tissues supported the hepatoprotection. It is concluded that the ethanolic extract of Bacopa monieri plant possess good hepatoprotective activity.  相似文献   
82.
In this paper we explore how the ‘employable’ student and ‘ideal’ future creative worker is prefigured, constructed and experienced through higher education work placements in the creative sector, based on a recent small-scale qualitative study. Drawing on interview data with students, staff and employers, we identify the discourses and practices through which students are produced and produce themselves as neoliberal subjects. We are particularly concerned with which students are excluded in this process. We show how normative evaluations of what makes a ‘successful’ and ‘employable’ student and ‘ideal’ creative worker are implicitly classed, raced and gendered. We argue that work placements operate as a key domain in which inequalities within both higher education and the graduate labour market are (re)produced and sustained. The paper offers some thoughts about how these inequalities might be addressed.  相似文献   
83.
Although widely touted as important, there is little evidence regarding the influence of teaching experience on elementary teachers' science subject matter knowledge (SMK). To better understand this phenomenon, we administered an assessment of science topics taught in the fifth and sixth grades to 169 preservice teachers, 231 fifth-grade teachers, and 208 sixth-grade teachers. We then compared the mean scores of teachers at different stages in the career cycle using one-way and two-way ANOVA and explored the relationship between SMK scores and years of teaching experience using regression analysis. Findings indicate that (i) being assigned to a specific grade level had an impact on teachers' SMK for topics included in the grade level, (ii) teachers' SMK scores were lower later in their careers for both science topics they had never taught and for science topics they were responsible for teaching, and (iii) results differed for fifth and sixth grades. This study adds to the existing literature through the examination of a large sample of elementary teachers, with teachers of varying years of experience, while focusing on the science topics these teachers are responsible for teaching. The results of this study provide strong evidence that (i) years of experience teaching specific science topics is associated with the development of teachers' knowledge of these topics, and (ii) teaching experience, what teachers do in the context of their everyday practice, can be an effective means of self-directed learning for teachers. There is also evidence that this influence is not uniform across years of teaching experience or science topics taught. These findings raise important implications about future research into the mechanism of SMK development through teaching experience and teacher grade-level assignments.  相似文献   
84.
Acquiring both published and unpublished documents produced in Africa is, generally, a difficult task due to the existing poor state of bibliographic control and the publishing industry. It is even more difficult to obtain unpublished documents in a specialized area of study such as demography--a diffuse area which cuts across several disciplines. This paper discusses the problems encountered on acquisition trips to some African countries to acquire unpublished population material. To help solve the problems, the Population Association of Africa must persuade its members to send copies of their publications to population libraries and documentation centers in their individual countries for dissemination to the other users in Africa. The various organizations and institutions in Africa engaged in the teaching and research of population studies should have an agreement to exchange copies of their theses. The Economic Commission for Africa (ECA) and the Organization of African Unity (OAU) should make representations to the various African member countries on the need to disseminate the results of vital censuses and surveys conducted. Finally, the Population Information Network for Africa (POPIN-AFRICA) with its coordinating unit at the population division of ECA should ensure that all the nodes of the network have the financial and other resources to be able to acquire the relevant documents needed for their operations.  相似文献   
85.
86.
Given the high prevalence of HIV/AIDS in Kenya, more Kenyans now find themselves in the role of informal caregiver for a family member or multiple family members living with HIV/AIDS. However, there exists little research on how these individuals cope. The present study explores coping responses among caregivers for family members living with HIV/AIDS in Kenya. An exploratory factor analysis of the Brief COPE yielded five factors, with strong loadings on Emotional Support and Instrumental Support. Implications for using the Brief COPE in research and clinical practice among Kenyans are discussed.  相似文献   
87.
Solitons emerge as non-perturbative solutions of non-linear wave equations in classical and quantum theories. These are non-dispersive and localised packets of energy — remarkable properties for solutions of non-linear differential equations. In the presence of such objects, the solutions of Dirac equation lead to the curious phenomenon of ‘fractional fermion number’. Under normal conditions the fermion number takes strictly integral values. In this article, we describe this accidental discovery and its manifestation in polyacetylene chains, which has led to the development of organic conductors. (left) Kumar Rao is a Postdoctoral Fellow at PRL, Ahmedabad. He is interested in particle physics phenomenology as probed in particle colliders and formal aspects of quantum field theory. (right) Narendra Sahu is currently a postdoctoral fellow at Lancaster University, UK. His main research area includes Cosmology and Astroparticle physics. Currently he is working on dark matter and matter anti-matter asymmetry of the universe. (center) P K Panigrahi’s research interests are in the area of quantum computation, solitons in Bose Einstein condensates & nonlinear optical media. He is also deeply interested in science education and derives pleasure from long weekend walks.  相似文献   
88.
In the last few decades, researchers are paying more and more attention to study the connections between sports and urban development. The main purpose of this study is to examine the changing role of sports in urban development through the example of Debrecen and to present the differences between the various historical periods. As a result, it can be concluded that on the one hand, in the inter-war years and in the period after 2000, the broader influence of sports was recognised, and local government made special efforts to use sports for the development of local economy, as well as for the improvement of the image of the city. By contrast, in the period between 1945 and 1990, the main approach used was from the side of mass sports, with satisfying the needs of workers and the general population deemed as the most important. On the other hand, from the early 1930s, i.e. from the beginning of urban planning (with the exception of the period during World War II and the 1950s), the leaders of the city paid special attention to ensure that sports facilities be included in the local development plans of Debrecen.  相似文献   
89.
Frances Brill 《Literacy》2004,38(2):83-89
It is sometimes assumed that the strongest opportunities for developing imagination and empathy through children's writing lie in narrative starting points, whereas other less obviously literary writing forms are more readily associated with functional literacy. Consequently, writing regarded as non‐literary is rarely analysed with these qualities in mind. This paper presents an exploratory, textual analysis of children's letter‐writing texts, which aims to identify and describe the uses of imagination and empathy. It is suggested that imaginative strategies were integral to this textual construction and that the significance of imagination and empathy in writing development is worthy of further exploration.  相似文献   
90.
The rapid urbanization and industrialization involve an unsustainable use of natural systems,leading to various problems in cities.The urban hydrological system experiences fluctuating amount of surfac...  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