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   320篇
  免费   0篇
  国内免费   3篇
安全科学   1篇
废物处理   4篇
环保管理   16篇
综合类   170篇
基础理论   44篇
污染及防治   51篇
评价与监测   18篇
社会与环境   13篇
灾害及防治   6篇
  2017年   3篇
  2014年   5篇
  2013年   4篇
  2012年   4篇
  2011年   11篇
  2010年   8篇
  2009年   13篇
  2008年   10篇
  2007年   12篇
  2006年   11篇
  2004年   8篇
  2003年   5篇
  2002年   7篇
  2001年   9篇
  2000年   8篇
  1999年   4篇
  1998年   3篇
  1997年   5篇
  1996年   4篇
  1995年   3篇
  1994年   3篇
  1993年   4篇
  1989年   3篇
  1983年   3篇
  1981年   3篇
  1973年   4篇
  1965年   10篇
  1964年   5篇
  1962年   3篇
  1961年   8篇
  1960年   3篇
  1959年   4篇
  1957年   7篇
  1956年   3篇
  1955年   8篇
  1954年   3篇
  1952年   3篇
  1950年   4篇
  1941年   4篇
  1940年   4篇
  1939年   7篇
  1937年   3篇
  1935年   4篇
  1931年   3篇
  1930年   5篇
  1926年   2篇
  1925年   2篇
  1922年   5篇
  1919年   2篇
  1914年   2篇
排序方式: 共有323条查询结果,搜索用时 15 毫秒
301.
302.
303.
304.
305.
306.
太湖流域北部潜在洪涝风险区分析及影响评估   总被引:2,自引:3,他引:2  
太湖流域历来遭受严重的洪涝灾害,并且近年来有不断加重的趋势。本文选择太湖流域北部的无锡市作为典型研究地区,研究其洪涝的危险性并进行潜在损失评估。人类活动,包括修筑圩区、森林破坏、人口增长、城市化等,对这个地区的洪涝形势有较大的影响;自然条件的变化使河道水位升高,洪涝历时缩短,洪峰增高。本文选择不同回归年(2,5,10,20,50年),结合地理信息系统分析模型,计算了潜在洪涝危险区域和洪涝损失,主要结论为:(1)人类活动已经改变了自然的洪涝形势,增大了汇流和洪涝;(2)洪涝危险区与降雨中心有关;(3)筑圩成功地保护了圩内的土地,缩短了洪涝历时,增高了圩外河道的洪涝水位;(4)经济发展使洪涝损失增加。  相似文献   
307.
308.
309.
Marine aquaculture is facing a variety of competing uses in densely populated coastal areas such as the coast of Kiel Bay. Thus, a major barrier for extending the marine aquaculture business could be the lack of suitable space for “offshore farming”. Moreover, in public opinion the aquaculture sector is often associated with a negative image derived from environmental concerns. It might therefore be expected that planning aquaculture installations in Kiel Bay & Fjord would face resistance both from other offshore stakeholders and the public. This study therefore addressed the question whether arguments and criteria can be found that may contribute to a greater support and positive image of local aquaculture enterprise, thus fostering political support for this sector as well. Indeed, a widespread regional survey showed less public reservation towards aqua-cultural business in Kiel Fjord than initially expected. However, expanding the entrepreneurship in the regional aqua-cultural sector will only be successful if the installations can avoid a significant deterioration of the water quality in Kiel Fjord, e.g. through excessive emissions of nutrients from net cages. An important step forward toward this goal is the concept of IMTA = Integrated Multi-Trophic Aquaculture. The IMTA concept spatially integrates nutrient emitting installations such as fish net cages with installations of nutrient extracting organisms, e.g. mussels and algae. Based on spatial analyses of marine environmental parameters and through modelling of nutrient mass balances (emitted versus extracted nutrient quantities) possible locations, types and sizes of aquaculture installations can be determined.  相似文献   
310.
Participatory approaches to conservation are viewed as a plausible alternative to the old ‘fortress conservation’ approach. The design and implementation of these approaches in developing countries have tended to embrace community participation through decentralized governance mechanisms in the past three decades. However, sustainable conservation approaches that maintain community livelihoods while conserving biodiversity are challenged with meeting both objectives. In addressing this challenge, little attention has been given to an empirical analysis of community’s satisfaction levels on how they participated in the design and implementation of this approach. In this article, we use a mixed method approach using both quantitative and qualitative data to examine levels of satisfaction and participation of local communities in the Idodi-Pawaga Wildlife Management Area (WMA), south-western Tanzania. We find that social economic factors (e.g. age, household size, gender, number of years living in the same location and participation/non-participation) influence, in different ways, the satisfaction levels of community’s participation towards the WMA creation. Due to inadequate participation, we find that the WMA design and implementation process failed from the beginning to actively involve the local communities and this has resulted in the near absence of the promised economic benefits from wildlife conservation. We suggest that participation should go beyond the simple information sharing to actively engage the local communities in key planning activities from the beginning of any WMA programme. It is also important to take into consideration their levels of satisfaction with the process of decision-making if meaningful decentralized governance is to be achieved.  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