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   130篇
  免费   3篇
安全科学   3篇
废物处理   8篇
环保管理   21篇
综合类   44篇
基础理论   18篇
污染及防治   29篇
评价与监测   4篇
社会与环境   6篇
  2023年   1篇
  2021年   3篇
  2020年   2篇
  2019年   1篇
  2017年   4篇
  2016年   3篇
  2015年   6篇
  2014年   4篇
  2013年   7篇
  2012年   8篇
  2011年   9篇
  2010年   2篇
  2009年   6篇
  2008年   6篇
  2007年   6篇
  2006年   9篇
  2005年   3篇
  2004年   3篇
  2003年   6篇
  2002年   4篇
  2001年   6篇
  2000年   1篇
  1999年   4篇
  1998年   3篇
  1997年   2篇
  1996年   1篇
  1994年   1篇
  1993年   1篇
  1992年   2篇
  1991年   3篇
  1989年   1篇
  1987年   1篇
  1986年   3篇
  1981年   1篇
  1971年   1篇
  1968年   1篇
  1964年   1篇
  1959年   1篇
  1954年   1篇
  1926年   1篇
  1925年   1篇
  1924年   1篇
  1923年   1篇
  1922年   1篇
排序方式: 共有133条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
This paper presents a study of recycling stations in the municipality of Borl?nge, Sweden. The main objectives were to measure volume weights of recyclables, to facilitate future planning of collection intervals and bin/container volume, and to investigate the general attitudes among the public towards waste management in general and recycling stations in particular. Volume weights measured in bins/containers were: paper/newsprint: 297 kg/m3, glass packaging: 297 kg/m3, metal packaging: 81.7 kg/m3, paper packaging: 27.8 kg/m3, plastic packaging: 28.1 kg/m3. The recycling stations have been in use since 1994. Most visitors (90%) arrived by car but said the visit to the recycling station was not the main purpose of the trip. The results from the interviews indicated that the people who use the recycling stations have found ways to incorporate waste sorting into their everyday lives, with the help of information, design of the collection system and environmental concerns.  相似文献   
66.
67.
It is currently estimated that 40 million hectares worldwide are cultivated through no-tillage systems (Derpsh, 1998). Small family farms account for less than 50,000ha, half of them located in South America's Southern Cone (Wall, 1998). Many hypotheses have been offered to explain why so few small farmers have adapted to this method. The most simplistic ones relate this limited adoption to small farmers' traditionalism and to their rejection of innovation. Others point to the low technological development of animal-drawn equipment needed for this technology or the low educational level of family farmers.Results of work done in the Center-South of Paraná, Southern Brazil, by AS-PTA1 in partnership with the region's Forum of Family Farmers Organizations, challenge these hypotheses and draw attention to the need for new approaches and processes of research and extension if the goal is to disseminate and implement appropriate no-tillage systems among family farmers. One requisite is to lower production costs of this method through elimination of herbicides and using green manure and cover crops that shift the crop-weed balance in favor of crops.  相似文献   
68.
Mining is an important part of the South African economy and has been the driver of much of the economic development of the country. However, the small–scale mining subsector still has to realise its full potential. A small–scale mine has been defined as a mining activity employing less than 50 people and with an annual turnover of less than 7.5 million Rand and includes artisanal mines. Small–scale miners are involved in many commodities but there appears to be a bias towards gold, diamonds and quarrying for construction materials, including brickclays. Small–scale mining is regulated by the same legislation (i.e., for the environment, labour, mineral rights, exploration and mining permitting, and skills development) as large–scale mining, though compliance is low, particularly where artisanal mining in concerned. The effective participation of small–scale miners in the mining sector is hampered by their lack of skills, i.e., technical, business and management, and their limited access to mineral deposits, capital and markets. Some of these hindrances have been inherited from the imbalances of the colonial and apartheid eras and continue to act as barriers, making entrance to the industry difficult. For those who have entered the industry out of desperation, as is the case with most artisanal miners, their activities result in negative impacts evident in the inefficient, unsafe and environmentally unfriendly operations. With the advent of the new political dispensation in South Africa, a new era is dawning for the country’s small–scale mining subsector. This has resulted in a change of attitude and new government policies which have led to special programmes being put in place to promote the subsector. Intervention strategies for the support of small–scale mining (some of which are already in operation) include programmes for kickstarting mineral beneficiation and value–addition projects, development of appropriate technologies and skills and technology transfer. Proponents of small–scale mining see a well–regulated industry as being the cornerstone of future rural economic development, particularly for previously disadvantaged communities in the poverty nodes.  相似文献   
69.
In the management literature, heuristics are often conceived of as a source of systematic error, whereas logic and statistics are regarded as the sine qua non of good decision making. Yet, this view can be incorrect for decisions made under uncertainty, as opposed to risk. Research on fast and frugal heuristics shows that simple heuristics can be successful in complex, uncertain environments and also when and why this is the case. This article describes the conceptual framework of heuristics as adaptive decision strategies and connects it with the managerial literature. We review five classes of heuristics, analyze their common building blocks, and show how these are applied in managerial decision making. We conclude by highlighting some prominent opportunities for future research in the field. In the uncertain world of management, simple heuristics can lead to better and faster decisions than complex statistical procedures. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
70.
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