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   53篇
  免费   2篇
安全科学   1篇
环保管理   16篇
综合类   9篇
基础理论   14篇
污染及防治   8篇
评价与监测   2篇
社会与环境   5篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2019年   2篇
  2018年   5篇
  2017年   4篇
  2015年   3篇
  2014年   2篇
  2013年   3篇
  2012年   5篇
  2011年   3篇
  2010年   2篇
  2009年   2篇
  2008年   3篇
  2006年   3篇
  2004年   1篇
  2002年   3篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1994年   1篇
  1992年   1篇
  1990年   1篇
  1982年   1篇
  1981年   1篇
排序方式: 共有55条查询结果,搜索用时 0 毫秒
51.
This research compares environmental volunteering among students in South Korea and the US (n = 3612). Given differing environmental histories of these countries, we explore whether and to what extent volunteer proclivity and intensity varies, and potential factors that explain existing variation. Findings suggest that American students are more likely to volunteer for, and devote time to, environmental causes, while South Korean students differ on socio-economic correlates of such behaviour. In a global society, understanding determinants of environmental volunteer participation is critical to the management of environmental NGOs that are involved in broad-based and participatory planning, educating stakeholders and legitimising environmental advocacy.  相似文献   
52.
ABSTRACT: A study of stream base flow and NO3‐N concentration was conducted simultaneously in 51 subwatersheds within the 116‐square‐kilometer watershed of East Mahantango Creek near Klingerstown, Pennsylvania. The study was designed to test whether measurable results of processes and observations within the smaller watersheds were similar to or transferable to a larger scale. Ancillary data on land use were available for the small and large watersheds. Although the source of land‐use data was different for the small and large watersheds, comparisons showed that the differences in the two land‐use data sources were minimal. A land use‐based water‐quality model developed for the small‐scale 7.3‐square‐kilometer watershed for a previous study accurately predicted NO3‐N concentrations from sampling in the same watershed. The water‐quality model was modified and, using the imagery‐based land use, was found to accurately predict NO3‐N concentrations in the subwatersheds of the large‐scale 116‐square‐kilometer watershed as well. Because the model accurately predicts NO3‐N concentrations at small and large scales, it is likely that in second‐order streams and higher, discharge of water and NO3‐N is dominated by flow from smaller first‐order streams, and the contribution of ground‐water discharge to higher order streams is minimal at the large scale.  相似文献   
53.
Ambio - A horizon scan was conducted to identify emerging and intensifying issues for biodiversity conservation in South Africa over the next 5–10 years. South African biodiversity...  相似文献   
54.
Industrial production processes contribute the most diverse group of emissions to air, water, and land pollution. These forms of pollution were the initial focus of environmental regulations requiring control efforts. Under optimum conditions, industrial waste streams pass through some type of treatment to minimize toxicity prior to being released into the environment. Business, government, and interest groups have previously assumed that industrial productivity and environmental quality were diametrically opposed. In other words, enhanced industrial productivity resulted in environmental damage and, conversely, environmental protection resulted in costs to business. However, companies that have implemented pollution prevention (P2) strategies to address their environmental problems have usually found that their facility's productivity can improve, while at the same time waste and pollution can be reduced. Where previous environmental strategies focused on end-of-pipe control efforts, P2 strategies are implemented at the design or process phase. While there are many examples of individual companies successfully implementing P2, consensus shows P2 adoption by the business community advancing at a rate far slower than expected. Most government agencies that currently promote P2 are not typically viewed as credible sources of innovation by industry. Publicly Owned Treatment Works (POTWs), however, may be able to capitalize on their dual status as respected members of the local community as well as experts in waste management thus serving as credible proponents of P2. The paper discusses how POTWs are working with industrial users to promote P2, as well as their interest in doing so and their requirements for technical assistance. Survey results are provided that describe how POTW personnel in the State of Illinois believe they could best promote P2.  相似文献   
55.
Atmospheric deposition of nitrogen (N) and sulfur (S) containing compounds affects soil chemistry in forested ecosystems through (1) acidification and the depletion of base cations, (2) metal mobilization, particularly aluminum (Al), and iron (Fe), (3) phosphorus (P) mobilization, and (4) N accumulation. The Bear Brook Watershed in Maine (BBWM) is a long-term paired whole-watershed experimental acidification study demonstrating evidence of each of these acidification characteristics in a northeastern U.S. forested ecosystem. In 2003, BBWM soils were studied using the Hedley fractionation procedure to better understand mechanisms of response in soil Al, Fe, and P chemistry. Soil P fractionation showed that recalcitrant P was the dominant fraction in these watersheds (49%), followed by Al and Fe associated P (24%), indicating that a majority of the soil P was biologically unavailable. Acidification induced mobilization of Al and Fe in these soils holds the potential for significant P mobilization. Forest type appears to exert important influences on metal and P dynamics. Soils supporting softwoods showed evidence of lower Al and Fe in the treated watershed, accompanied by lower soil P. Hardwood soils had higher P concentrations in surface soils as a result of increased biocycling in response to N additions in treatments. Accelerated P uptake and return in litterfall overshadowed acidification induced P mobilization and depletion mechanisms in hardwoods.  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