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   1584篇
  免费   48篇
  国内免费   32篇
管理学   187篇
民族学   5篇
人口学   33篇
丛书文集   70篇
理论方法论   151篇
综合类   677篇
社会学   389篇
统计学   152篇
  2024年   2篇
  2023年   18篇
  2022年   11篇
  2021年   20篇
  2020年   42篇
  2019年   42篇
  2018年   52篇
  2017年   48篇
  2016年   39篇
  2015年   29篇
  2014年   80篇
  2013年   292篇
  2012年   94篇
  2011年   58篇
  2010年   48篇
  2009年   75篇
  2008年   73篇
  2007年   75篇
  2006年   90篇
  2005年   68篇
  2004年   57篇
  2003年   58篇
  2002年   54篇
  2001年   57篇
  2000年   35篇
  1999年   28篇
  1998年   18篇
  1997年   17篇
  1996年   17篇
  1995年   9篇
  1994年   14篇
  1993年   7篇
  1992年   5篇
  1991年   5篇
  1990年   5篇
  1989年   6篇
  1988年   3篇
  1987年   7篇
  1986年   1篇
  1984年   1篇
  1983年   2篇
  1981年   1篇
  1977年   1篇
排序方式: 共有1664条查询结果,搜索用时 46 毫秒
1.
The literature on urban farming in Sub-Saharan African cities reveals that most studies have been conducted in Eastern, Southern and Central African cities. A few have focused on West Africa, including Sierra Leone, Guinea Bissau, and Cameroon. In Ghana there is a paucity of information on urban farming. The purpose of this paper is to examine the status of urban cultivation in Accra, Ghana's capital, reviewing existing research, and to present new empirical findings on urban cultivation emphasizing on its history, nature, practices, problems, potentials and urban planning implications.  相似文献   
2.
粉煤灰在废水处理中的应用   总被引:7,自引:0,他引:7  
介绍了粉煤灰的结构及物理化学特性,处理废水的机理,综述了国内外利用粉煤灰处理各种废水的最新研究成果。目前利用粉煤灰处理废水主要应用于城市污水、印染废水、造纸废水、制药废水、电废水、重金属废水及含酚、含氟废水的处理。同时介绍了几种粉煤灰改性的方法及应用前景。  相似文献   
3.
液-气喷射器在电厂炉烟水处理中的应用研究   总被引:1,自引:1,他引:0  
本文通过对液-气喷射器的结构及工作原理进行分析,针对呼和浩特市发电厂中50MW容量机组,并提出将该喷射器用于循环冷却水处理系统中,从而有效防止凝汽器铜管表面结垢,不但可以节省费用,减轻环境污染,而且可以提高机组热交换效率,降低煤耗。  相似文献   
4.
在《TRIPS协议》中适用国民待遇原则 ,既要遵守《WTO协定》的规定 ,又要遵守《TRIPS协议》框架下各条约的规定。《TRIPS协议》中国民待遇原则适用对象的标准有国籍标准、居所标准和实质关联标准。《TRIPS协议》适应了世界贸易和经济的发展  相似文献   
5.
讨论了利用废锌渣制备氯化锌的理论依据、工艺流程、影响因素及控制方法  相似文献   
6.
Complete and partial diallel cross designs are examined as to their construction and robustness against the loss of a block of observations. A simple generalized inverse is found for the information matrix of the line effects, which allows evaluation of expressions for the variances of the line-effect differences with and without the missing block. A-efficiencies, based on average variances of the elementary contrasts of the line-effects, suggest that these designs are fairly robust. The loss of efficiency is generally less than 10%, but it is shown that specific comparisons might suffer a loss of efficiency of as much as 40%.  相似文献   
7.
文章将建设农村全面小康社会作为一项系统工程进行研究,既指出建设农村全面小康社会要依靠农业自身的发展,又阐述了从其他途径建设农村全面小康的可能性、必要性。  相似文献   
8.
教师期望效应是教师对学生的期望在学生的未来发展中得到证实的现象,它反映了教师对学生的态度会影响学生发展的方向和程度,开展该现象的研究对教师观念的改变和学生的健康发展均有重要意义。对教师期望效应的种类、理论模型及国外的相关研究进行了介绍,探讨了其对教育现实的一些重要启示。  相似文献   
9.
Liberia has gone through civil crisis for over a decade which has resulted in the destruction of infrastructure and disruption of basic services delivery particularly in Monrovia, the capital city. Most of the 1.3 million people living in Monrovia are without adequate environmental sanitation and waste management services which situation poses a serious health risk to the residents. The current waste management service coverage is less than 20% and disposal is by indiscriminate open dumping. In 2003, there were series of outbreaks of cholera epidemics in the city during which time a total of 26,651 cases were reported with many dying.The waste management plan was initiated as an exit strategy of UNICEF following an intervention response programme to assist the Monrovia City Corporation (MCC) whose capacity in this area had been crippled as a result of years of war, through the provision of support in solid waste collection and disposal.The objectives of the plan were to:
(a) Improve waste management services delivery in the city.
(b) Strengthen the ability of the MCC to plan and manage the waste services delivery.
(c) Enhance cooperation of service beneficiaries through comprehensive and effective health education and service promotional campaign.
(d) Enhance revenue generation and community participation through the promotion of private sector and CBOs/NGOs active involvement in the waste management service delivery.
The general methodology adopted for the assignment entailed the following:Desk study and review of existing reports on Water and Environmental Sanitation (WES) in Monrovia and other relevant literature, consultation with stakeholders, site visits and participatory planning which aimed at soliciting the opinions of the various stakeholders involved with the respective components to capture their aspirations and experiences. It also covered collection and analysis of available information and data to facilitate the plan preparation and facilities design.The three-phased strategy (short, medium and long term) covering a period of 10 years (August 2004–December 2014), recommended a combination of technical options for collection based on the pursuit of staged development to allow for the adoption of realistically attainable standards within a framework of continuous and systematic improvements as economic conditions improved and new knowledge gained through practice. The plan sought to blend the capacity within the City Corporation with that of the private sector and NGOs/CBOs to respond to the diverse service demands of the city taking into consideration housing and infrastructural conditions, service costs and cost recovery to ensure sustainability. It also identified sources of financing and allocated financing responsibilities to facilitate effective plan implementation.  相似文献   
10.
医疗消费的经济学探讨   总被引:1,自引:0,他引:1  
医疗消费是一个倍受大众关注的特殊的社会行为 ,关于如何正确认识与看待这一问题 ,理论界尚未展开更深入的研究。为此 ,从经济学的角度来探讨医疗消费这个关系到每个人切身利益的问题 ,并浅析公费医疗在市场经济条件下的不合理性 ,是十分必要的。  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