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   17053篇
  免费   15篇
财政金融   2681篇
工业经济   783篇
计划管理   2612篇
经济学   3920篇
综合类   482篇
运输经济   9篇
旅游经济   15篇
贸易经济   4566篇
农业经济   18篇
经济概况   1366篇
信息产业经济   44篇
邮电经济   572篇
  2024年   1篇
  2023年   5篇
  2022年   5篇
  2020年   10篇
  2019年   15篇
  2018年   2311篇
  2017年   2066篇
  2016年   1219篇
  2015年   99篇
  2014年   102篇
  2013年   132篇
  2012年   452篇
  2011年   1957篇
  2010年   1843篇
  2009年   1528篇
  2008年   1521篇
  2007年   1872篇
  2006年   72篇
  2005年   396篇
  2004年   466篇
  2003年   554篇
  2002年   257篇
  2001年   65篇
  2000年   50篇
  1999年   4篇
  1998年   20篇
  1997年   3篇
  1996年   16篇
  1995年   3篇
  1993年   2篇
  1991年   1篇
  1989年   1篇
  1987年   2篇
  1986年   14篇
  1982年   1篇
  1981年   2篇
  1978年   1篇
排序方式: 共有10000条查询结果,搜索用时 885 毫秒
41.
42.
43.
44.
45.
46.
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   
47.
48.
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   
49.
For a variety of reasons, this article argues, electricity must be seen by policy‐makers in South Africa not as the sole provider of all future household energy needs, but rather as one component of an energy mix which includes such ‘transitional’ fuels as coal, gas and paraffin. The reasons for this are that electricity is expensive for poor households; it is subject to power failures and disconnections for non‐payment; the poor find it difficult to monitor and to control their consumption; appliances are expensive and several are required to make best use of electricity; people prefer other fuels because they are familiar and have strong personal and cultural associations, and because Eskom is not trusted owing to its past ties to illegitimate local authorities and misunderstanding of electricity and how its use is monitored and charged for. Further, it is mistaken to equate ‘development’ with total electrification: most developed countries have fuel mixes which include gas and coal, particularly for cooking and heating. Accepting an affordable fuel mix for the poor in particular would focus attention on the problems currently associated with paraffin, gas and coal, namely fires, poisoning and air pollution.  相似文献   
50.
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