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   122篇
  免费   2篇
安全科学   9篇
废物处理   2篇
环保管理   18篇
综合类   13篇
基础理论   32篇
环境理论   1篇
污染及防治   38篇
评价与监测   6篇
社会与环境   2篇
灾害及防治   3篇
  2022年   1篇
  2021年   3篇
  2019年   2篇
  2018年   1篇
  2017年   3篇
  2016年   2篇
  2015年   4篇
  2014年   2篇
  2013年   23篇
  2012年   2篇
  2011年   8篇
  2010年   4篇
  2009年   4篇
  2008年   1篇
  2007年   5篇
  2006年   3篇
  2005年   3篇
  2004年   3篇
  2003年   5篇
  2002年   6篇
  2001年   2篇
  2000年   5篇
  1999年   3篇
  1998年   1篇
  1997年   4篇
  1996年   1篇
  1995年   2篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1986年   1篇
  1985年   5篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1973年   1篇
  1971年   1篇
排序方式: 共有124条查询结果,搜索用时 15 毫秒
31.
This paper develops a model to aid Coast Guard managers in formulating appropriate policies with respect to planning for various types of equipment required to contain major pollution incidents. The model is elaborated in terms of three primary stages of response: offloading, containment, and removal. The zero order rule of chance constrained programming is used to obtain a deterministic equivalent of the original chance constrained model. This is then replaced by a goal programming formulation to allow for plans that come “as close as possible” to desired quality and risk levels for each pertinent region and type of incident. Numerical examples illustrate potential uses of the model with special emphasis on its value for budgetary (equipment) planning by central management that extends to evaluation of risk and performance quality levels, as well as the usual dual evaluator approaches for evaluating initially prescribed levels for equipment and their efficiency coefficients.  相似文献   
32.
Impacts of urbanization on aquatic ecosystems are intensifying as urban sprawl spreads across the global land base. The urban stream syndrome (USS) identifies “symptoms” associated with urban development including changes in biotic communities, hydrology, water chemistry, and channel morphology. Direct relationships between road density (as surrogate of urbanization) and indicators of the USS were identified for streams in the Toronto region. Significant negative relationships were revealed between road density and biological (fish and benthic macroinvertebrate) richness, diversity, and fish Index of Biotic Integrity scores. Significant positive relationships were found between road density and tolerant fish/benthic macroinvertbrates, benthos Family Biotic Index scores, mean summer stream temperature, stream flashiness, and several water quality variables. Analysis of biological data showed that only four fish species and a reduced number of benthic macroinvertebrate families remained at the most urbanized sites. Road density was found to be a major determinant in both the fish and benthic macroinvertebrate community structure.  相似文献   
33.
No single particle size measuring device was found suitable in both the fine and ultrafine particle size regimes, however, combinations of devices have been used successfully. Methods of measurement and applications in the laboratory and field are discussed.  相似文献   
34.
35.
This is the third in a series of papers discussing the experience of electric utilities in applying baghouse technology for the collection of particulate matter at coal-fired electric power generating plants. The series presents new data obtained in research sponsored by the Electric Power Research Institute (EPRI) on reverse-gas and shake/deflate cleaned baghouses, and specifically addresses a number of unresolved issues in the design and operation of these units. This paper provides an overview of the design and operating characteristics of baghouses now in place in the utility industry. In addition, it discusses three key issues in design and operation: the relationships among dust cake weight and chemical composition, air-to-cloth ratio, and pressure drop; fabric selection; and bag life.  相似文献   
36.
This study investigated the effects of increased temperature and salinity, two potential impacts of global climate change, on the toxicity of two common pesticides to the estuarine grass shrimp, Palaemonetes pugio. Larval and adult grass shrimp were exposed to the fungicide chlorothalonil and the insecticide Scourge® under standard toxicity test conditions, a 10°C increase in temperature, a 10 ppt increase in salinity, and a combined increased temperature and salinity exposure. Toxicity of the fungicide chlorothalonil increased with temperature and salinity. Toxicity of the insecticide Scourge® also increased with temperature; while increased salinity reduced Scourge® toxicity, but only in adult shrimp. These findings suggest that changes in temperature and salinity may alter the toxicity of certain pesticides, and that the nature of the effect will depend on both the organism's life stage and the chemical contaminant. Standard toxicity bioassays may not be predictive of actual pesticide toxicity under variable environmental conditions, and testing under a wider range of exposure conditions could improve the accuracy of chemical risk assessments.  相似文献   
37.
38.
Environmental studies and environmental sciences programs in American and Canadian colleges and universities seek to ameliorate environmental problems through empirical enquiry and analytic judgment. In a companion article (Part 1) we describe the environmental program movement (EPM) and discuss factors that have hindered its performance. Here, we complete our analysis by proposing strategies for improvement. We recommend that environmental programs re-organize around three principles. First, adopt as an overriding goal the concept of human dignity??defined as freedom and social justice in healthy, sustainable environments. This clear higher-order goal captures the human and environmental aspirations of the EPM and would provide a more coherent direction for the efforts of diverse participants. Second, employ an explicit, genuinely interdisciplinary analytical framework that facilitates the use of multiple methods to investigate and address environmental and social problems in context. Third, develop educational programs and applied experiences that provide students with the technical knowledge, powers of observation, critical thinking skills and management acumen required for them to become effective professionals and leaders. Organizing around these three principles would build unity in the EPM while at the same time capitalizing on the strengths of the many disciplines and diverse local conditions involved.  相似文献   
39.
Research was conducted in Nottinghamshire, England to investigate public attitudes regarding home energy efficiency issues. Quantitative data were collected in the form of a postal survey, achieving over three hundred responses. Additionally, predominantly qualitative data were collected in semi-structured interviews in 15 homes. The issues investigated included the grant-funded energy efficiency measures installed by the public, the organisations providing grants, the means by which the recipients were referred to the organisations, and the public's preferences regarding energy efficiency advice. Findings were made about the local authority's success in encouraging the take-up of energy efficiency grants, about the public's preferences for the means by which advice should be provided, about trust relating to energy efficiency grants provided by gas and electricity suppliers, and about people's knowledge of the most effective energy efficiency measures. Additional findings were drawn about specific energy efficiency issues, including old heating systems and compact fluorescent light bulbs.  相似文献   
40.
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