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   2671篇
  免费   126篇
  国内免费   107篇
安全科学   776篇
废物处理   16篇
环保管理   526篇
综合类   694篇
基础理论   246篇
环境理论   2篇
污染及防治   118篇
评价与监测   140篇
社会与环境   133篇
灾害及防治   253篇
  2024年   4篇
  2023年   31篇
  2022年   34篇
  2021年   70篇
  2020年   81篇
  2019年   54篇
  2018年   29篇
  2017年   82篇
  2016年   96篇
  2015年   98篇
  2014年   84篇
  2013年   146篇
  2012年   140篇
  2011年   224篇
  2010年   120篇
  2009年   168篇
  2008年   143篇
  2007年   163篇
  2006年   137篇
  2005年   144篇
  2004年   120篇
  2003年   135篇
  2002年   95篇
  2001年   68篇
  2000年   69篇
  1999年   60篇
  1998年   34篇
  1997年   44篇
  1996年   28篇
  1995年   31篇
  1994年   24篇
  1993年   36篇
  1992年   25篇
  1991年   17篇
  1990年   9篇
  1989年   9篇
  1988年   5篇
  1987年   8篇
  1986年   4篇
  1985年   3篇
  1984年   2篇
  1983年   3篇
  1981年   9篇
  1980年   3篇
  1979年   4篇
  1978年   2篇
  1977年   3篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有2904条查询结果,搜索用时 875 毫秒
471.
基于RS与GIS的长江三角洲生态环境脆弱性综合评价   总被引:4,自引:0,他引:4       下载免费PDF全文
使用空间主成分分析法构建评价指标体系,采用层次分析法确定指标权重,结合遥感数据与地理信息系统软件,对长江三角洲生态环境脆弱性进行了综合评价,并对脆弱性成因进行了分析. 结果表明,长江三角洲生态环境极度和重度脆弱区主要分布在其中部的太湖流域和浙江中西部,占整个研究区的20.10%;轻度和中度脆弱区遍布于整个研究区,占55.25%;微度脆弱区主要分布在江苏北部和浙江东部,占24.65%. 总体来看,长江三角洲大部分区域的生态环境属轻度和中度脆弱. 影响长江三角洲生态环境脆弱性的自然因素有≥35 ℃日数、旱涝分布、海拔高度、归一化植被指数(NDVI)年累加值、景观多样性指数和土壤侵蚀强度;人为因素有人均耕地面积、人均水资源、人均废水排放量、人均废气排放量、化肥施用强度、土地利用变化、“三废”综合利用产品产值、人口密度和GDP. 极度和重度脆弱区生态环境的主要特征是自然灾害发生频率大、资源匮乏、污染强度大、土壤侵蚀严重和生物多样性低.   相似文献   
472.
环境风险全过程评估与管理模式研究及应用   总被引:11,自引:2,他引:9       下载免费PDF全文
基于环境风险“全过程管理”与“优先管理”的理念,提出了环境风险全过程评估与管理的概念框架和理论体系,涵盖了风险源识别、受体易损性评估、环境风险表征、风险应急控制决策以及风险事故损失后评估等关键步骤.并以某化工园区企业为例,以硝基苯储罐塌陷为初始事件,采用蝴蝶结方法进行风险源识别,得到硝基苯储罐泄漏事件蝴蝶结,通过GIS空间分析方法揭示居民对地表水水源污染易损性的空间分异,分析结果不仅为事故安全防范与应急控制提供关键节点,而且有助于在日常风险管理中增强受体抗风险能力.  相似文献   
473.
基于SCI发文的中国生态学研究态势文献计量分析   总被引:1,自引:0,他引:1  
邢颖  孔红梅  刘天星 《生态环境》2010,19(2):447-452
采用文献计量学的方法,基于《科学引文索引》数据库近十年的检索结果,定量分析中国生态学领域发文的主题、时间、作者、机构、合作国家、被引频次、期刊分布等数据,系统分析中国生态学领域近十年的研究发展态势、研究热点、研究投入主体、国际合作和研究水平等趋势和特征。基于检索得到的3316篇SCI论文数据,研究认为:我国生态学领域的研究发展迅速。研究的热点主要是分子标记、气候变化、生物多样性、土地利用、分类学、物种、草原、荒漠化、模型、多态性等方面。研究主题的关联性随时间有增加的趋势。588个第一作者发文机构中,中国科学院发文量最高,大学近年的研究发展迅猛。生态学领域篇均作者人数是2.2人。国际合作的主要国家是美国。我国生态学研究的SCI发文篇均被引频次为6。第一作者机构为中国机构的论文被引用情况逊于外国机构。中国生态学领域研究最重要的发文期刊是ECOLOGICAL MODELLING和JOURNAL OF ARID ENVIRONMENTS。  相似文献   
474.
The current research provides guidance on the prevention and mitigation of dust explosion using a Quantitative Risk Management Framework (QRMF). Using concepts drawn from previous studies, the framework consists of three main steps: (i) a new combined safety management protocol, (ii) the use of DESC (Dust Explosion Simulation Code) and FTA (Fault Tree Analysis) to assess explosion consequences and likelihood, respectively, and (iii) application of the hierarchy of controls (inherent, engineered and procedural safety). QRMF assessment of an industrial case study showed that the original process was at high risk. DESC simulations and Probit equations determined the destructive percentages. FTAs revealed high probabilities of explosion occurrence; in addition, detailed individual and societal risks calculations were made, before and after the framework was applied. Based on the hierarchy of controls technique, the framework showed significant risk reduction to the point where the residual risk was acceptable for the process.  相似文献   
475.
The key objective of this paper is the presentation of a new risk assessment tool for underground coal mines based on a simplified semi-quantitative estimation and assessment method.In order to determine the risk of explosion of any work process or activity in underground coal mines it is necessary to assess the risk. The proposed method is based on a Risk Index obtained as a product of three factors: frequency of each individual scenario Pucm, associated severity consequences Cucm and exposure time to explosive atmospheres Eucm. The influence of exposure time is usually not taken into account up to now. Moreover, the exposure to explosive atmospheres may affect factors of hazardous event probability as much as its consequences. There are many definitions of exposure to explosive atmospheres but in the case of underground coal mines the exposure is defined as frequency risk of firedamp and coal dust. The risk estimation and risk assessment are based on the developed of a risk matrix.The proposed methodology allows not only the estimation of the explosion risk but also gives an approach to decide if the proposal investment is well-justified or not in order to improve safety.  相似文献   
476.
This paper presents a novel quantitative risk analysis process for urban natural gas pipeline networks using geographical information systems (GIS). The process incorporates an assessment of failure rates of integrated pipeline networks, a quantitative analysis model of accident consequences, and assessments of individual and societal risks. Firstly, the failure rates of the pipeline network are calculated using empirical formulas influenced by parameters such as external interference, corrosion, construction defects, and ground movements. Secondly, the impacts of accidents due to gas leakage, diffusion, fires, and explosions are analyzed by calculating the area influenced by poisoning, burns, and deaths. Lastly, based on the previous analyses, individual risks and social risks are calculated. The application of GIS technology helps strengthen the quantitative risk analysis (QRA) model and allows construction of a QRA system for urban gas pipeline networks that can aid pipeline management staff in demarcating high risk areas requiring more frequent inspections.  相似文献   
477.
Natech accidents at industrial plants are an emerging risk with possibly serious consequences. For the mitigation of natech risk, authorities need to identify natech prone areas in a systematic manner. In order to facilitate probabilistic natech risk mapping, a unified methodology was developed that is based on the estimation of on-site natural hazard parameters, determination of damage probabilities of plant units, and assessment of probability and severity of possibly triggered natech events. The methodology was implemented as an on-line, extensible risk assessment and mapping software framework called RAPID-N, which allows rapid local and regional natech risk assessment and mapping with minimal data input. RAPID-N features an innovative data estimation framework to complete missing input data, such as on-site natural hazard parameters and plant unit characteristics. The framework is also used for damage assessment and natech consequence analysis, and allows easy modification of input parameters, dynamic generation of consequence models according to data availability, and extension of models by adding new equations or substituting existing ones with alternatives. Results are presented as summary reports and interactive risk maps, which can be used for land-use and emergency planning purposes by using scenario hazards, or for rapid natech consequence assessment following actual disasters. As proof of concept, the framework provides a custom implementation of the U.S. EPA's RMP Guidance for Offsite Consequence Analysis methodology to perform natech consequence analysis and includes comprehensive data for earthquakes. It is readily extendible to other natural hazards and more comprehensive risk assessment methods.  相似文献   
478.
在对我国安全生产信息化建设现状调研的基础上,结合国内外相关资料文献及笔者多年为企业提供安全生产信息化建设解决方案的工作经验,分析了目前我国安全生产信息系统的分类和应用方向,以及企业在安全生产信息化建设过程中存在的问题,如缺乏统一规范和总体规划、投入结构不合理等。针对企业安全生产信息化建设中存在的诸多问题,提出了建设应对措施及建议。对指导企业开展安全生产信息化建设,保证系统科学性、实用性等方面具有重要意义。  相似文献   
479.
本文对信息获取过程中的信息来源分析方法、信息采集方法、信息检索方法、信息加工方法进行了简要介绍,并将上述信息获取方法用于宏观环境督察信息获取过程中,研究了宏观环境督察信息获取机制,并对宏观环境督察信息获取过程进行了详细地分析,为后续的宏观环境督察信息发布提供了基础。  相似文献   
480.
Risk assessment/management frameworks employed around the world to guide environmental decision-making were analyzed for their approaches to developing risk management objectives and the decision criteria necessary for environmental policy implementation. Frameworks from the Netherlands, the UK, Sweden, Australia/New Zealand, Canada, and the USA were considered. Progress in refining the scientific basis for risk assessment/management has been made, but there has been little parallel development in defining the mechanisms by which available scientific information may be used to define risk management goals or identify and select between management options using a priori decision criteria. The lack of detailed guidance on the setting and achievement of risk management goals that appropriately balance technical information and public input remains an important challenge to the use and practice of all risk assessment/management frameworks.  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