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   3153篇
  免费   225篇
  国内免费   382篇
安全科学   346篇
废物处理   106篇
环保管理   792篇
综合类   1408篇
基础理论   361篇
环境理论   24篇
污染及防治   167篇
评价与监测   50篇
社会与环境   451篇
灾害及防治   55篇
  2024年   9篇
  2023年   51篇
  2022年   69篇
  2021年   83篇
  2020年   134篇
  2019年   116篇
  2018年   119篇
  2017年   193篇
  2016年   211篇
  2015年   162篇
  2014年   147篇
  2013年   321篇
  2012年   256篇
  2011年   322篇
  2010年   219篇
  2009年   167篇
  2008年   127篇
  2007年   170篇
  2006年   141篇
  2005年   100篇
  2004年   96篇
  2003年   86篇
  2002年   66篇
  2001年   68篇
  2000年   59篇
  1999年   51篇
  1998年   26篇
  1997年   25篇
  1996年   22篇
  1995年   13篇
  1994年   22篇
  1993年   12篇
  1992年   12篇
  1991年   8篇
  1990年   12篇
  1989年   3篇
  1988年   5篇
  1987年   3篇
  1985年   2篇
  1984年   4篇
  1983年   2篇
  1982年   4篇
  1981年   6篇
  1980年   6篇
  1979年   8篇
  1978年   5篇
  1977年   5篇
  1976年   3篇
  1972年   2篇
  1971年   2篇
排序方式: 共有3760条查询结果,搜索用时 62 毫秒
881.
关于建立我国资源节约型经济体系的认识   总被引:6,自引:0,他引:6  
从可持续发展角度看,我国资源节约型经济体系机制应在坚持集约经济和适应消费的基础上,强调社会生产与消费两者间的平衡和协调发展,欲达此目的,加快市场经济体系的完善和国家宏观指导是保障这一体系机制正常运转的根本条件。  相似文献   
882.
我国可持续能源系统发展的途径探讨   总被引:4,自引:0,他引:4  
本文从大规模发展风能所要解决的问题入手,通过借鉴石油和天然气的经验,提出了以租赁方式发展风能的设想,并对我国利用租赁方式发展风能所要解决的问题进行了讨论。  相似文献   
883.
可再生能源资源评价体系与方法   总被引:8,自引:0,他引:8  
本文根据可再生能源资源的特性以及与技术、市场之间的内在联系,构建了可再生能源的资源评价体系,分析了资源量、生产率、生产经济性及不确定性分析等各环节中的具体评价方法和指标框架,并提出了最小和最大经济获利开发量以度量资源生产的经济性潜力  相似文献   
884.
In univariate frequency analysis, the return period of an event has a one-to-one correspondence with its characteristic value, and the response of the hydraulic structure to hydrological load expressed by the hydrological event is monotonic. Thus, the design criteria of the hydraulic structure can be equivalently represented by the return period of the hydrological event, and consequently, design event-based design parameters evaluated have been widely used in practical engineering. However, the monotonic correspondence between the return period of the hydrological event and the response of the hydraulic structure does not exist in the multivariate context, and hydrological load with a larger joint return period does not always produce a more unsafe response. Misunderstandings of concepts of return periods of hydrological event, and estimation of hydrological design events usually take place in multivariate frequency analysis. This study theoretically derives the relations between different types of joint return periods, joint return period and its marginal return periods, the occurrence of bivariate extreme events and their return periods, and then the theoretical framework is tested. Results from the case contribute to the understanding of bivariate return periods of hydrological event, and the results demonstrate that design criteria cannot be equivalently represented by joint return periods of hydrological load, and design parameters of the hydraulic structure should not be determined by multivariate hydrological design events.  相似文献   
885.
ABSTRACT

The imminent development of a number of offshore wind farms in the Republic of Ireland presents a sizable opportunity to stimulate the Irish economy through the growth of an indigenous and globally competitive offshore wind supply chain. This study uses a value chain analysis to evaluate the economic and employment potential of the offshore wind sector for Ireland. The analysis is based on the expenditure on products and services required to develop an offshore wind farm, the planned capacity of projects in the pipeline, and the ability of Irish companies to supply the sector. Results suggest that by 2030, 2.5–4.5GW of domestic offshore wind development could create between 11,424 and 20,563 supply chain jobs and generate between €763 m and €1.4bn in gross value added. This is the first study to estimate domestic GVA potential for the sector.  相似文献   
886.
ABSTRACT The definition and comparison of alternative water resource systems designed to meet long-range goals (say 60 years) is illustrated by a case study in Hungary. A comprehensive cost-effectiveness approach is adapted to define goals, specifications, criteria, alternatives and their capabilities. Specifications include demands given in probabilistic terms. The comparison of alternative systems is based on 12 criteria, one of which is the balance between total energy consumed and peak energy produced. Important factors involving social elements, such as flood protection and land and forest use, are described both as monetary quantities and as qualitative appreciations. Five alternative systems are defied involving flat land reservoirs, pumped storage reservoirs, interbasin transfer, and conjunctive use of surface and ground water. International cooperation is then used to rank systems and reduce the problem to a tradeoff between only two alternatives.  相似文献   
887.
Power plant water consumption (evaporative water loss) for various river temperature standards is presented for existing and proposed power plants located along the Missouri and Upper Mississippi Rivers in the MAPP geographical area. Thermodynamic and economic models are combined to evaluate the cooling related water consumption at various river thermal standards. The existing thermal standards and a number of other hypothetical thermal regulations including the extreme cases of no thermal standards and no allowable heated discharges are examined to show the dependence on thermal standards of power production related water consumption. A critical appraisal of the cost of thermal standards in terms of water consumption is thereby possible so that subjective assessments of the standards can proceed with full knowledge of the tradeoffs involved between the “water costs” of power production and environmental enhancement.  相似文献   
888.
ABSTRACT: Forecasts of future urban water demand traditionally have been made by the projection of historic trends in per capita consumption and population. This paper outlines the use of two deterministic models to forecast the residential component of urban water demand. The models incorporate specific representation of the activities which result in water consumption at each residence. Predictions of water use can then be made by modeling the changes expected in the number of these activities and the consumption for each such activity.  相似文献   
889.
ABSTRACT: The effects of energy development on the water resources of the Colorado River and Great Basin regions is expected to be substantial. Complex physical, economic and institutional interactions may be expected. Most research on these impacts appears single purpose, fragmented, uncoordinated, and often inaccessible to potential users - particularly those with responsibility for energy/water policy and program decisions. A comprehensive, integrative framework for assessing alternative water allocation decisions is outlined, taking a heuristic decision making model for evaluating impacts on maximization of gross (or net) regional product, and regional social welfare, and for assessing the region's contribution to national objectives. The suggested model provides a structure for application and integration of data of various kinds to a range of situations arising from possible impacts from energy proposals. The focus is on water and energy relationships but the model may provide a framework for comprehensive analysis of a variety of environmental actions and resulting system perturbations and effects.  相似文献   
890.
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