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   382篇
  免费   11篇
  国内免费   8篇
安全科学   70篇
废物处理   1篇
环保管理   90篇
综合类   111篇
基础理论   40篇
污染及防治   11篇
评价与监测   36篇
社会与环境   11篇
灾害及防治   31篇
  2023年   1篇
  2022年   1篇
  2021年   5篇
  2020年   11篇
  2019年   6篇
  2018年   4篇
  2017年   7篇
  2016年   8篇
  2015年   8篇
  2014年   8篇
  2013年   10篇
  2012年   12篇
  2011年   18篇
  2010年   20篇
  2009年   22篇
  2008年   13篇
  2007年   30篇
  2006年   18篇
  2005年   19篇
  2004年   28篇
  2003年   24篇
  2002年   22篇
  2001年   12篇
  2000年   19篇
  1999年   10篇
  1998年   16篇
  1997年   6篇
  1996年   7篇
  1995年   5篇
  1994年   7篇
  1993年   4篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   4篇
  1984年   2篇
  1981年   1篇
  1979年   1篇
排序方式: 共有401条查询结果,搜索用时 15 毫秒
141.
体育教学过程中,教学效果的好坏取决于师生双方对过程的调控程度,而对技能教学的调控,则依据教师的教学反馈和学生的自我反馈来实现。在体育教学过程中,教学反馈与自我反馈的有机结合,是提高教学质量的关键。  相似文献   
142.
143.
Specifying information needs: improving the working methodology   总被引:1,自引:1,他引:0  
Specification of information needs is an important step in the design of monitoring networks. Within the framework of Monitoring Strategy 2000+, a programme of the Dutch Directorate General of Public Works and Water Management (Rijkswaterstaat) which seeks to provide innovation in the monitoring sector, a method has been developed to link water management policy to monitoring through specification of information needs. Over the past 2 years, this method has been applied in several projects within the Rijkswaterstaat organisation. Use of this method has led to improvements in the monitoring practice and was judged very positively by the people involved. Nevertheless, the main obstacle to employing the method was the actual translation of policy matters into information products. A special study is carried out, focusing on this aspect within the method, to provide the participants of a project with a mental framework that enables them to clearly specify their information needs. The major requirements for this mental framework are that all participants have a clear view of the process (system), and that they are able to relate their contribution to this process and to the contributions of others (transparency). The first step of the process is to focus the attention of stakeholders on the information they will actually need for decision-making. The next step is to confront the different expressed opinions through the method of the 'devil's advocate', which implies criticising the results of the first step by finding as many as possible arguments against these opinions. This should force the stakeholders to better specify their arguments. The method, its improvements and the results of one pilot project will be discussed in this paper. Electronic Publication  相似文献   
144.
随着工业化、城市化的飞速发展,我国经济社会面临的资源环境瓶颈约束日益突出,实现经济发展和环境保护的同步推进是当前工作的重要内容,环境保护将扮演更为重要的角色。实施绿色供应链管理有利于改善高能耗高污染问题,提高企业生产效率,增强核心竞争力,促进企业和社会的可持续发展。欧盟和美国在推行绿色供应链管理方面成果显著,汲取其先进的政策和实践经验,对中国推进绿色供应链具有重要的借鉴意义。  相似文献   
145.
以核电站核污染扩散预警技术为研究对象,基于环保指挥自动化系统C4ISRE,通过整合WRF、HYSPLIT、Unidata IDV、AGI STK、Arc GIS系统等构建核污染扩散单一合成图SIP(Single Integrated Picture),并通过SIP对核污染扩散进行详细分析,进而实现对核污染应急处置的制信息权。研究表明:当研究区实际的天气系统具备了本例模拟的气象特征时,即主体风向为局部区域东北风3~4级,局部区域西北风6~7级,发生与日本福岛核事故同样等级的事故,12个小时后,受影响的居民区主要为谢屯镇、炮台镇、李店镇、普兰店市、无名区1。其中,炮台镇的大部分区域浓度为10 Pbq,面积为2.66 km 2,东北方向部分区域浓度为100 Pbq,面积为0.03 km~2;普兰店市西南部区域浓度为10 Pbq,面积为8.00 km~2,东北部区域浓度为100 Pbq,面积为0.033 km 2;李店镇东北区域浓度为1 Pbq,面积为0.93km~2;无名区1南部区域浓度为1 Pbq,面积为4.50 km~2。  相似文献   
146.
During the last few years in the Netherlands an integrated environmental policy has been developed. Solving environmental problems by means of effective and efficient solutions requires that the entire environmental cycle be considered in order to take all relevant compartments and aspects into account. Four different phases can be identified during the treatment of an environmental problem by management: recognition, formulation, solution, and control.Some qualitative and quantitative aspects of the information demand of environmental policy are explored. Special attention is given to the consequences of the integral approach in environmental policy in terms of information requirements. The process of information supply starts with an analysis of the demand. Subsequently data from the environmental cycle have to be selected, aggregated, and presented adequately. Further, integrated environmental policy puts increased demands on the associative power of environmental information systems.  相似文献   
147.
本文通过本单位档案目标管理考核, 提出进一步完善环保档案管理工作, 是环保事业的需要。从以下四方面谈一谈认识。  相似文献   
148.
ABSTRACT: A Geographic Information System (GIS) based non‐point source runoff model is developed for the Las Vegas Valley, Nevada, to estimate the nutrient loads during the years 2000 and 2001. The estimated nonpoint source loads are compared with current wastewater treatment facilities loads to determine the non‐point source contribution of total phosphorus (TP), total nitrogen (TN), and total suspended solids (TSS) on a monthly and annual time scale. An innovative calibration procedure is used to estimate the pollutant concentrations for different land uses based on available water quality data at the outlet. Results indicate that the pollutant concentrations are higher for the Las Vegas Valley than previous published values for semi‐arid and arid regions. The total TP and TN loads from nonpoint sources are approximately 15 percent and 4 percent, respectively, of the total load to the receiving water body, Lake Mead. The TP loads during wet periods approach the permitted loads from the wastewater treatment plants that discharge into Las Vegas Wash. In addition, the GIS model is used to track pollutant loads in the stream channels for one of the subwatersheds. This is useful for planning the location of Best Management Practices to control nonpoint pollutant loads.  相似文献   
149.
ABSTRACT: Investigating natural, potential, and human-induced impacts on hydrologic systems commonly requires complex modeling with overlapping data requirements, plus massive amounts of one- to four-dimensional data at multiple scales and formats. Given the complexity of most hydrologic studies, the requisite software infrastructure must incorporate many components including simulation modeling and spatial analysis with a flexible, intuitive display. Integrating geographic information systems (GIS) and scientific visualization systems (SVS) provides such an infrastructure. This paper describes an integrated system consisting of an orographic precipitation model, a GIS, and an SVS. The results of this study provide a basis for improving the understanding of hydro-climatic processes in mountainous regions. An additional benefit of the integrated system, the value of which is often underestimated, is the improved ability to communicate model results, leading to a broader understanding of the model assumptions, sensitivities, and conclusions at a management level.  相似文献   
150.
The present study concerns a hazardous event which occurred in an industrial storage tank of a ground insecticide. A preliminary post-accident approach of the hazard evaluation is performed. The rapid report of the presence of an unstable functional group in the active product and of its potential thermal instability (CHETAH indices) has led to complete this examination by an experimental study of thermal analysis using isotherm exposition measurement (DTA) or with temperature programming by differential scanning calorimetry (DSC) and oxidability tests (BAM). The apparent kinetics of decomposition of the active matter of the ground insecticide has been represented by a global Arrhenius law.

A model designed for the simulation of heterogeneous thermal runaways based on the numerical solution of the transient mass and energy balances has been further applied to define the critical conditions of the storage and simulate its behavior.

The results obtained during this analysis with the experienced feedback allowed us on one side to explain the hazardous event and especially on the other side to modify the operating protocol of the conditions of formulation of the active matter on the inert mineral support.  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