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   7086篇
  免费   269篇
  国内免费   483篇
安全科学   825篇
废物处理   51篇
环保管理   1413篇
综合类   2827篇
基础理论   490篇
污染及防治   504篇
评价与监测   953篇
社会与环境   510篇
灾害及防治   265篇
  2024年   11篇
  2023年   104篇
  2022年   118篇
  2021年   218篇
  2020年   229篇
  2019年   112篇
  2018年   132篇
  2017年   202篇
  2016年   267篇
  2015年   291篇
  2014年   332篇
  2013年   382篇
  2012年   367篇
  2011年   600篇
  2010年   259篇
  2009年   443篇
  2008年   419篇
  2007年   401篇
  2006年   331篇
  2005年   296篇
  2004年   285篇
  2003年   268篇
  2002年   235篇
  2001年   168篇
  2000年   194篇
  1999年   181篇
  1998年   166篇
  1997年   131篇
  1996年   95篇
  1995年   99篇
  1994年   117篇
  1993年   101篇
  1992年   59篇
  1991年   36篇
  1990年   25篇
  1989年   13篇
  1988年   15篇
  1987年   17篇
  1986年   18篇
  1985年   16篇
  1984年   12篇
  1983年   5篇
  1982年   10篇
  1981年   14篇
  1980年   7篇
  1979年   11篇
  1978年   6篇
  1977年   3篇
  1973年   6篇
  1968年   2篇
排序方式: 共有7838条查询结果,搜索用时 78 毫秒
1.
Over the past decades, the plastic production has been dramatically increased. Indeed, a category of small plastic particles mainly with the shapes of fragments, fibers, or spheres, called microplastics (particles smaller than 5 mm) and nanoplastics (particles smaller than 1 μm) have attracted particular attention. Because of its wide distribution in the environment and potential adverse effects to animal and human, microplastic pollution has been reported as a serious environment problem receiving increased attention in recent years. As one of the commonly detected emerging contaminants in the environment, recent evidence indicates that the concentration of microplastics show an increasing trend, for the reason that up to 12.7 million metric tons of plastic litter is released into aquatic environment from land-based sources each year. Furthermore, microplastic exposure levels of model organisms in laboratory studies are usually several orders of magnitude higher than those found in environment, and the microplastics exposure conditions are also different with those observed in the environment. Additionally, the detection of microplastics in feces indicates that they can be excreted out of the bodies of animal and human. Hence, great uncertainties might exist in microplastics exposure and health risk assessment based on current studies, which might be exaggerated. Policies reduce microplastic emission sources and hence minimize their environmental risks are determined. To promote the above policies, we must first overcome the technical obstacles of detecting microplastics in various samples.  相似文献   
2.
水环境系统脆弱性是水资源利用与生态环境研究的热点问题,通过研究水环境系统的内在机理,综合考虑影响水环境系统脆弱性的资源、环境、经济、社会等因素,借助驱动力-压力-状态-影响-响应-管理(DPSIRM)框架构建水环境系统脆弱性评价指标体系。在此基础上,构建基于变权灰色云模型的评价方法,对2004~2014年江苏省水环境系统脆弱性进行评价。结果表明:2004~2014年水环境系统脆弱性指数由47.056提高到63.210,脆弱性等级由“重度脆弱”演化为“中度脆弱”,并长期维持在“中度脆弱的”等级,2014年出现了向“轻度脆弱”状态转变的趋势。分析各个子系统对水环境系统脆弱性影响程度可知,影响子系统和响应子系统对江苏省水环境脆弱性系统的影响程度逐年增加;而压力子系统和管理子系统对水环境系统脆弱性的影响程度逐年下降;其它子系统对水环境系统脆弱性的影响维持在一定水平小幅度波动。  相似文献   
3.
• Isotope dilution method was developed for the determination of 27 PPCPs in water. • The established method was successfully applied to different types of water samples. • The correction effect of corresponding 27 ILSs over 70 d was investigated. • Benefit of isotopic dilution method was illustrated for three examples. Pharmaceuticals and personal care products (PPCPs) are a unique group of emerging and non-persistent contaminants. In this study, 27 PPCPs in various water samples were extracted by solid phase extraction (SPE), and determined by isotope dilution method using liquid chromatography coupled to tandem triple quadruple mass spectrometer (LC-MS/MS). A total of 27 isotopically labeled standards (ILSs) were applied to correct the concentration of PPCPs in spiked ultrapure water, drinking water, river, effluent and influent sewage. The corrected recoveries were 73%–122% with the relative standard deviation (RSD)<16%, except for acetaminophen. The matrix effect for all kinds of water samples was<22% and the method quantitation limits (MQLs) were 0.45–8.6 ng/L. The developed method was successfully applied on environmental water samples. The SPE extracts of spiked ultrapure water, drinking water, river and wastewater effluent were stored for 70 days, and the ILSs-corrected recoveries of 27 PPCPs were obtained to evaluate the correction ability of ILSs in the presence of variety interferences. The recoveries of 27 PPCPs over 70 days were within the scope of 72%–140% with the recovery variation<37% in all cases. The isotope dilution method seems to be of benefit when the extract has to be stored for long time before the instrument analysis.  相似文献   
4.
工业内窥镜是电站锅炉内部检验中不可或缺的设备,主要用来对集箱、减温器、受热面管等内部人眼无法观察到的地方进行检验,从而确定承压部件内部是否存在严重影响锅炉安全运行的缺陷.本文通过对锅炉内窥实例进行分析和总结,阐述内窥镜检查在锅炉内检中的重要性并给相关工作人员提供借鉴与参考.  相似文献   
5.
随着浙江"五水共治"工作的深化,宁波作为浙江"五水共治"的中坚力量,始终把"五水共治"作为全市工作的首要任务和突破重点。自1999年进行清淤后,月湖水质得到短期改善,然而治标不治本的治理措施,并没有让月湖水质得到根本改善。因此,对月湖进行科学有效的生态修复,针对性地处理水污染问题,使之重新焕发活力具有十分重要的意义。  相似文献   
6.
Reducing accident occurrence in petrochemical plants is crucial, thus appropriately allocating management resources to safety investment is a vital issue for corporate management as international competition intensifies. Understanding the priority of safety investment in a rational way helps achieve this objective.In this study, we targeted an acrylonitrile plant. First, Dow Chemical's Fire and Explosion Index (F&EI) identified the reaction process as having the greatest physical risk. We evaluated the severity of accidents in the reaction process using the Process Safety Metrics advocated by the Center for Chemical Process Safety (CCPS); however, this index does not express damages a company actually experience. To solve this problem, we proposed a new metric that adds indirect cost to CCPS metrics. We adopted fault tree analysis (FTA) as a risk assessment method. In identifying top events and basic events, we attempted to improve the completeness of risk identification by considering accidents from the past, actual plant operation and equipment characteristics, natural disasters, and cyber-attacks and terrorist attacks. Consequently, we identified the top events with high priority in handling because of serious accidents as fire/explosion outside the reactor, fire/explosion inside the reactor, and reactor destruction. The new CCPS evaluation index proposed in this study found that fire and explosion outside the reactor has the highest severity. We considered the creation of the fault tree (FT) diagram of the top event, estimating the occurrence probability, and identifying the risk reduction part and capital investment aimed at risk reduction. As an economically feasible selection method for risk reduction investment, using the difference in loss amounts before and after safety investments indicated investment priority.  相似文献   
7.
阐述了水生态健康的内涵与意义,从江苏省率先在太湖流域开展水生态环境功能分区管理的顶层设计,构建以水生态健康指标为核心的水生态健康评估技术体系,地方对照水生态环境功能区划的水生态分级管控目标开展的应用与实践结果等3个方面,回顾了江苏省太湖流域水生态健康评估工作的主要进展,提出了完善水生态健康评估技术体系和推进流域水生态健康评估工作的建议。  相似文献   
8.
近15a江苏省水源涵养功能时空变化与影响因素探析   总被引:2,自引:0,他引:2  
定量评估生态系统服务功能是合理利用自然资源、促进人地关系与可持续发展的基础。以江苏省为研究区,基于InVEST模型产水模块,定量分析了江苏省2000~2015年产水功能和水源涵养功能的时空变化特征,并采用回归分析和主成分分析法评估了水源涵养功能与社会经济要素之间的关系。结果表明:(1)江苏省多年平均产水量为571×108 m3/a,水源涵养总量78.39×108 m3/a;(2)2000~2010年江苏省水源涵养功能呈下降趋势,2010~2015年有所回升,考虑到降水因素,江苏省实际水源涵养功能持续降低;(3)土地利用变化使15a来水源涵养功能下降15.2×108 m3,降低幅度为16.9%;(4)流域尺度上水源涵养功能与江苏社会经济因素相关关系不显著。研究结果可以为土地利用优化、流域水资源管理提供科学参考和支持。  相似文献   
9.
介绍了瑞典的水环境保护法规政策、水环境保护机构、污水处理体系及其在水环境保护方面的特色做法。结合目前我国水环境管理所处的阶段,从顶层设计、宣传教育、项目管理、污染防治等方面,总结了瑞典经验对我国水环境保护工作的启示。  相似文献   
10.
Transport projects have numerous consequences for the environment, society and economy, and thus an EU Directive has stated a number of impacts that need to be assessed prior to any major intervention. This paper is set in a Danish context where the EU requirements have been adopted in the Environmental Impact Assessment (EIA) regulation along with national requirements. In recent years, however, the EIAs have been criticised for an inconsistent inclusion of impacts and unclear assessment process. A selection of EIAs is for this reason reviewed and compared to the EU Directive and corresponding works in Sweden and the UK to identify potential opportunities for improvements. From the literature study, an overview table with all potential relevant impacts for transport projects is set up to assist the EIA process. For the sake of simplicity and transparency, the impacts selected from this table should, however, be further reduced in number to ensure that only the most important impacts are included in the process. To further increase simplicity and transparency in the EIA process, a novel framework for assessing different types of impacts is proposed. In this framework, a comprehensive decision support tool involving stakeholders is in focus. The framework is supplemented with a procedure for generating objectives and presenting results in an appropriate way to the many stakeholders involved. The impacts overview table and the assessment techniques are applied to a case study to illustrate the process, and finally, conclusions and perspectives for future work within the field are set out.  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