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   387篇
  免费   29篇
  国内免费   19篇
安全科学   45篇
废物处理   5篇
环保管理   186篇
综合类   81篇
基础理论   43篇
污染及防治   3篇
评价与监测   29篇
社会与环境   27篇
灾害及防治   16篇
  2023年   4篇
  2021年   4篇
  2020年   9篇
  2019年   9篇
  2017年   11篇
  2016年   16篇
  2015年   11篇
  2014年   11篇
  2013年   17篇
  2012年   5篇
  2011年   23篇
  2010年   13篇
  2009年   17篇
  2008年   23篇
  2007年   26篇
  2006年   15篇
  2005年   20篇
  2004年   12篇
  2003年   6篇
  2002年   18篇
  2001年   12篇
  2000年   4篇
  1999年   7篇
  1998年   6篇
  1997年   4篇
  1996年   6篇
  1995年   2篇
  1994年   5篇
  1993年   4篇
  1992年   8篇
  1991年   6篇
  1990年   2篇
  1989年   3篇
  1988年   11篇
  1987年   8篇
  1985年   5篇
  1984年   5篇
  1982年   3篇
  1981年   3篇
  1980年   7篇
  1979年   5篇
  1978年   9篇
  1977年   5篇
  1976年   3篇
  1975年   2篇
  1974年   2篇
  1973年   4篇
  1972年   7篇
  1971年   9篇
  1970年   3篇
排序方式: 共有435条查询结果,搜索用时 406 毫秒
281.
Water quality monitoring network designs historically have tended to use experience, intuition, and subjective judgment in siting monitoring stations only sporadically. Better design procedures for optimizing monitoring systems with respect to multiple criteria decision analysis had rarely been put into practice up front when the needs for intensive monitoring became critical. This paper describes a systematic relocation strategy that is organized to identify several significant planning objectives and consider a series of inherent constraints simultaneously. The planning objectives considered in this analysis are designed to enhance the detection possibility for lower compliance areas, reflect the emphasis for different attainable water uses at different locations, promote the potential detection for the lower degradation areas of pollutants, increase the protection degree of those areas with higher population density in the proximity of the river system, and strengthen the pre‐warning capability of water quality for water intakes. The constraint set contains the limitations of budget, the equity implication, and the detection sensitivity in the water environment. A case study in the Kao‐Ping River Basin, South Taiwan, demonstrates the application potential of this methodology based on a seamless integration between the optimization and the simulation models. It enables identification of the optimal locational pattern stepwise using the embedded screening and sequencing capacity in a compromise programming model. However, a well calibrated and verified water quality model is an indispensable tool in support of this multiobjective evaluation. Extra sampling procedures become necessary for the sites with sparse environmental information. Comparison of planning outcomes of compromise programming is made against previously achieved analyses by using weighted programming and fuzzy programming.  相似文献   
282.
Multicriteria decision analysis (MCDA) increasingly is being applied in environmental impact assessment (EIA). In this article, two MCDA techniques, stochastic analytic hierarchy process and compromise programming, are combined to ascertain the environmental impacts of and to rank two alternative sites for Mexico City’s new airport. Extensive sensitivity analyses were performed to determine the probability of changes in rank ordering given uncertainty in the hierarchy structure, decision criteria weights, and decision criteria performances. Results demonstrate that sensitivity analysis is fundamental for attaining consensus among members of interdisciplinary teams and for settling debates in controversial projects. It was concluded that sensitivity analysis is critical for achieving a transparent and technically defensible MCDA implementation in controversial EIA.  相似文献   
283.
This paper introduces a violation analysis approach for the planning of regional solid waste management systems under uncertainty, based on an interval-parameter fuzzy integer programming (IPFIP) model. In this approach, several given levels of tolerable violation for system constraints are permitted. This is realized through a relaxation of the critical constraints using violation variables, such that the model's decision space can be expanded. Thus, solutions from the violation analysis will not necessarily satisfy all of the model's original constraints. Application of the developed methodology to the planning of a waste management system indicates that reasonable solutions can be generated through this approach. Considerable information regarding decisions of facility expansion and waste flow allocation within the waste management system were generated. The modeling results help to generate a number of decision alternatives under various system conditions, allowing for more in-depth analyses of tradeoffs between environmental and economic objectives as well as those between system optimality and reliability.  相似文献   
284.
根据梧州市郊县农村土地生态特征,利用逐步判别分析方法给出以各自然村为基础的区位点土地利用方法;并根据土地利用方向,结合果树经济效益和各种信息,应用规划理论给出本地区果树在满足诸条件时以种植46万亩橙、2万亩香蕉最为适宜。  相似文献   
285.
ABSTRACT: Land use planning in rapidly developing areas can serve as an effective tool for minimizing water quality impacts on ground water supplies. A land use management model applied to Jackson Township of the New Jersey Pine Barrens was developed. The management model consisted of a simulation model for the transport of nitrates from septic tank systems through the aquifer and a multiobjective, goal programming optimization model to determine population density restrictions using 208 areawide planning population projections. Results showed that growth may have to be curtailed in several areas of Jackson Township and that current population projections over the next 30 years may result in unacceptably high nitrate concentrations downgradient of Jackson Township. The management framework provides a flexible approach to land use planning.  相似文献   
286.
ABSTRACT A linear programming model to assess the cost-effectiveness of appropriate point and nonpoint phosphorus control measures was constructed for Carnegie Lake, an eutrophic lake located in Mercer County, New Jersey. The resultant model was tested for present and future conditions. Feasible solutions were obtained only after significant relaxation of receiving water quality standards. The high levels of point source treatment required to meet the in-stream water quality standards and the mesotrophic loading conditions suggest that a source control solution may not be feasible.  相似文献   
287.
Cost effective environmental control technology for utilities   总被引:1,自引:0,他引:1  
On September 24, 1998, new regulations announced by the US EPA require 22 eastern states plus the District of Columbia to develop state implementation plans to reduce ground-level ozone through the reduction of nitrogen oxide (NOx) emissions (Cooper, 1998). This plan calls for a 28% NOx cut in the summer time (1.2 million tons) by 2007. This calls for utilities to develop new, efficient, and robust post-combustion NOx control technologies. A new environmental control technology called low temperature oxidation (LTO) system, which can reduce NOx emissions below measurable levels (i.e. 2 ppm using process analyzers) at low temperature (125-325 °F), was awarded the best available control technology and the lowest available emission reduction technology by the US EPA in April 1998. Ozone is employed to oxidize nitric oxide (NO) to dinitrogen pentoxide (N2O5) at a low temperature in an oxidizer, which is then easily absorbed by water in a scrubber. Bench scale and pilot plant tests have shown that the LTO process can almost completely remove the NOx emissions (i.e. NOx emissions are below levels measurable using process analyzers). This proved that the LTO system is an attractive process to meet the stricter NOx regulations. There are multiple benefits of the LTO system besides removal of NOx emissions, includes reduction of SOx and CO emissions, and no secondary air emissions (NH3, N2O). In order to obtain minimum NOx emissions, extra ozone needs to be supplied. The cost of the process also increases nonlinearly as emissions decrease. This poses a challenging multiobjective optimization problem where emissions like NOx and SOx need to be minimized, while minimizing the system cost as well as extra ozone. This problem is addressed using a new and efficient multiobjective optimization framework. This framework will provide designs that are cost effective as well as environmentally friendly.  相似文献   
288.
ABSTRACT: The state of Minnesota seeks to reduce phosphorus loading to the Minnesota River by 40 percent from current levels. Looking at one major watershed in the river basin, we examined the cost effectiveness of targeting versus not targeting specific practices or regions within a watershed for controlling nonpoint phosphorus pollution from agriculture. Integrating biophysical simulation results from current and alternative farming systems with production cost and return estimates enabled us to analyze this policy. Our results indicated it is more cost effective to reduce nonpoint pollution by targeting particular regions or practices in a watershed compared to not targeting. Specifically, producers farming on cropland susceptible to erosion in close proximity to water will appreciably reduce phosphorus nonpoint pollution loading potential by switching from conventional tillage to conservation tillage and by reducing phosphorus fertilization levels to those recommended by the state extension service. Efforts to target those producers in the Minnesota River Basin could reduce potential transaction costs and compensation from “takings” by approximately $50 million (74 percent) over not targeting.  相似文献   
289.
介绍了基于GIS的铜陵市防震减灾计算机信息管理系统,着重介绍了在系统研制和开发过程中编程的关键技术及运用实现。  相似文献   
290.
Integrated resource assessment and sustainable land use   总被引:3,自引:0,他引:3  
Decision makers and planners in resource sectors recognize, at least in theory, the multiple uses of land, reflecting possible choices and options for society, and the need to evaluate the economic, social, and environmental implications of these choices. As such, the need for integrated resource management is now widely accepted in resource planning. This article contributes to the understanding of sustainable resource development through a specific case study. An integrated analytical system is developed and applied to the Peace River Region, British Columbia, Canada, to examine the impacts of a wide range of land-use options and policies upon the achievement of multiple resource use goals. The results indicate that an integrated approach in land resource analysis is not only possible but a necessary step in the move to develop procedures for assisting public decision makers in integrating the diverse functions of the land resource base and to revise demands or develop alternative strategies in order to move society closer to sustainable outcomes.  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