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   30737篇
  免费   277篇
财政金融   5360篇
工业经济   1780篇
计划管理   4644篇
经济学   6942篇
综合类   975篇
运输经济   86篇
旅游经济   211篇
贸易经济   6402篇
农业经济   682篇
经济概况   3307篇
信息产业经济   45篇
邮电经济   580篇
  2020年   144篇
  2019年   208篇
  2018年   2561篇
  2017年   2337篇
  2016年   1479篇
  2015年   262篇
  2014年   362篇
  2013年   1453篇
  2012年   777篇
  2011年   2380篇
  2010年   2157篇
  2009年   1840篇
  2008年   1904篇
  2007年   2216篇
  2006年   337篇
  2005年   648篇
  2004年   757篇
  2003年   889篇
  2002年   547篇
  2001年   351篇
  2000年   369篇
  1999年   242篇
  1998年   274篇
  1997年   268篇
  1996年   247篇
  1995年   230篇
  1994年   241篇
  1993年   287篇
  1992年   259篇
  1991年   239篇
  1990年   224篇
  1989年   190篇
  1988年   179篇
  1987年   174篇
  1986年   201篇
  1985年   251篇
  1984年   306篇
  1983年   253篇
  1982年   245篇
  1981年   266篇
  1980年   239篇
  1979年   243篇
  1978年   205篇
  1977年   192篇
  1976年   172篇
  1975年   141篇
  1974年   141篇
  1973年   125篇
  1972年   83篇
  1969年   68篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
51.
52.
53.
54.
55.
56.
57.
Construction kits have played a significant part in nurturing the growth and development of the minds and manipulation-based skills of children (and adults) in formal and non-formal education settings. These kits have origins rooted in the representation of the built world and now have a diversity of form and function, including technical versions with moving parts. This article examines some of the historically based ideas that lie behind the role that kits may have in terms of physical modelling. The article traces the transformation of kits from simple bricks and blocks into more complicated pieces for space-filling and achieving the transfer of forces and motion. This transformation occurred during the Victorian era when the influence of the ideas of educationalists and, perhaps rather strangely, exponents of early aviation, played major roles in determining the diversity of forms of construction kit and modelled possibilities that are now to be seen in classrooms and homes. The article ends with a review of some of the lessons from the past and present that will need to be considered in relation to concrete modelling in schools for the future. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
58.
59.
In this article the impact of technology education, as a new learning area (subject) in the curriculum, on in-service teacher education in South Africa is described in order to ascertain the extent of the impact. The research on which this article is based draws on a variety of experiences and observations in the field at grassroots level (in particular an outreach project in rural communities). The envisaged impact of technology education on South African schools, communities, teacher educators and teachers, the range of in-service teacher education that is required, and the impacts in urban and rural areas are discussed. Finally a number of concluding remarks are made about the extent of the impact of the inclusion of technology education in the new National Curriculum Statement and whether the situation has changed since the implementation of a pilot technology education project in 1998. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
60.
One Pleistocene mystery is why early North Americans eradicated their large, potentially domesticable animals (e.g., horses), whereas early Europeans did not. A commonly‐held hypothesis is that European species were evasive due to co‐evolution with hominids, whereas North American animals were naïve and unable to adapt quickly enough when experienced human hunters arrived from Eurasia. We explore this hypothesis with a paleoeconomic model of co‐evolution that integrates human hunting investments and wildlife population responses. We find that investments in hunting ability, based on the relative scarcity of prey species, could have mattered more than wildlife ‘naivety’ in explaining the extinction.  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