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   4753篇
  免费   495篇
  国内免费   1490篇
安全科学   499篇
废物处理   274篇
环保管理   719篇
综合类   3151篇
基础理论   755篇
污染及防治   481篇
评价与监测   168篇
社会与环境   312篇
灾害及防治   379篇
  2024年   27篇
  2023年   108篇
  2022年   178篇
  2021年   219篇
  2020年   199篇
  2019年   201篇
  2018年   141篇
  2017年   222篇
  2016年   265篇
  2015年   274篇
  2014年   285篇
  2013年   394篇
  2012年   458篇
  2011年   510篇
  2010年   326篇
  2009年   299篇
  2008年   236篇
  2007年   318篇
  2006年   311篇
  2005年   238篇
  2004年   189篇
  2003年   178篇
  2002年   155篇
  2001年   162篇
  2000年   144篇
  1999年   104篇
  1998年   103篇
  1997年   77篇
  1996年   69篇
  1995年   72篇
  1994年   44篇
  1993年   71篇
  1992年   38篇
  1991年   30篇
  1990年   25篇
  1989年   8篇
  1988年   5篇
  1987年   7篇
  1986年   7篇
  1984年   3篇
  1983年   2篇
  1982年   5篇
  1981年   5篇
  1980年   4篇
  1979年   2篇
  1977年   6篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1971年   2篇
排序方式: 共有6738条查询结果,搜索用时 31 毫秒
961.
962.
The functional safety requirement is widely applied in the process plant industry in accordance with the international standards, such as IEC and ISA. The requirement is defined as safety integrity level (SIL) based on the risk reduction concept for protection layers, from original process risk to tolerable risk level. Although the standards specify both, the Prevention System and the Emergency System, as level of protection layers, the standards specify in detail only the use of the Prevention System (i.e., Safety Instrumented System (SIS)). The safety integrity level is not commonly allocated to the Emergency System (e.g., Fire and Gas System, Emergency Shutdown System and Emergency Depressuring System). This is because the required risk reduction can be normally achieved by only the Prevention System (i.e., SIS and Pressure Safety Valve (PSV)). Further, the risk reduction level for the Emergency System is very difficult to be quantified by the actual SIL application (i.e., evaluated based on the single accident scenario, such as an accident from process control deviation), since the escalation scenarios after Loss of Containment (LOC) greatly vary depending on the plant design and equipment. Consequently, there are no clear criteria for evaluating the Emergency System design. This paper aims to provide the functional safety requirement (i.e., required risk reduction level based on IEC 61508 and 61511) as design criteria for the Emergency System.In order to provide clear criteria for the Emergency System evaluation, a risk reduction concept integrated with public’s perception of acceptable risk criteria is proposed and is applied to identify the required safety integrity level for the Emergency System design. Further, to verify the safety integrity levels for the Emergency Systems, the probabilistic model of the Emergency Systems was established considering each Emergency System (e.g., Fire and Gas System, Emergency Shutdown System and Emergency Depressuring System) relation as the Overall Emergency System. This is because the Overall Emergency System can achieve its goal by the combined action of each individual system, including inherent safe design, such as separation distance.The proposed approach applicability was verified by conducting a case study using actual onshore Liquefied Natural Gas Plant data. Further, the design criteria for Emergency Systems for LNG plants are also evaluated by sensitivity analysis.  相似文献   
963.
This paper describes part of a programme of work undertaken at the Health and Safety Laboratory (HSL) to investigate the behaviour of selected water-reactive chemicals. Following an accidental release, such substances react exothermically with any water present, generating acidic vapours. The STAWaRS (Source Term Assessment of Water Reactive Substances) software was developed for the Health and Safety Executive (HSE) by ESR Technology to model this complex process. The aims of the study described here were to provide experimental validation of the heats of hydrolysis used within STAWaRS, and to perform sensitivity studies on selected STAWaRS input parameters.The heat of hydrolysis of acetyl chloride was measured and showed good correlation with the value used within STAWaRS. Some of the variables that influence the severity of acetyl chloride spills are examined, with reference to predictions made by the STAWaRS model. The heats of hydrolysis of titanium tetrachloride previously measured at HSL are also discussed, and the effect of adopting these experimentally derived values for modelling spills is shown for a hypothetical land use planning case. This study demonstrates the importance of using experimentally validated values for STAWaRS input parameters.  相似文献   
964.
欧日中实施GHS政策的对比和思考   总被引:2,自引:0,他引:2  
通过研究欧盟、日本和我国实施全球化学品统一分类和标签制度(GHS)的基本情况,并从实施GHS的框架体系、实施GHS的时间节点、GHS的危险类别和GHS危险类别的判定,4个方面对欧盟、日本和我国实施GHS的现状进行重点研究。通过对比分析得出我国当前实施GHS主要存在4个方面的问题,即缺乏实施GHS的综合法律、实施GHS缓冲期的设置存在问题、缺乏开展GHS分类的配套指南、没有合理的运用"积木原则"。结合我国的实际情况提出3个方面的建议:适时推动我国GHS法律法规体系的建设、在各部门的协作下编制我国的GHS分类指南、合理的运用"积木原则"。通过分析表明:欧盟实施的GHS政策最为完善且力度最强,日本次之;由于充分利用"积木原则",欧盟的GHS类别与日中存在一定的差异;欧日中在数据运用和GHS危险判定原则上存在差异。  相似文献   
965.
本文简迷了皮肤防护器材--化学防护服(衣)化学防护性能试验与评价用标准物质的重要性,系统地概述了外军化学防护服(衣)化学防护性能试验与评价用标准物质的研究现状,并提出了我国化学防护服(衣)防护性能试验与评价用标准物质研制过程中应注意的一些问题.  相似文献   
966.
系统介绍了宝钢环境信息化系统建设架构、功能、特点,以及对污染减排、环境自动监测及信息化技术进行有效融合后的应用实践,并对该信息化系统在提高环境监控能力,完善系统建设上提出扩展监控范围、提升功能等构想.  相似文献   
967.
大型渡槽结构动力学研究进展   总被引:1,自引:0,他引:1  
大型渡槽是灌区生命线工程中的关键性建筑物,其在地震及风载作用下的安全性已是渡槽建设的瓶劲,也是国内外研究的热点。渡槽结构的抗震、减震和抗风技术的核心是渡槽结构动力学的问题,而渡槽结构动力学系属流固耦合(FSI)系统的动力学范畴。在已有研究的基础上,首先对渡槽结构FSI系统模型的研究进行了总结和评述;然后简述了渡槽结构动力特性和响应的求解技术以及抗震、隔震、减震与抗风技术的研究概况;最后总结了渡槽结构动力学的研究进展,提出了该学科进一步研究的内容和方法。  相似文献   
968.
Steckley M  Doberstein B 《Disasters》2011,35(3):465-487
This paper presents the results of primary research with 40 survivors of the 2004 Indian Ocean tsunami in two communities: Khao Lak (n=20) and Koh Phi Phi Don (n=20), Thailand. It traces tsunami survivors' perceptions of vulnerability, determines whether residents felt that the tsunami affected different communities differently, identifies the populations and sub-community groups that survivors distinguished as being more vulnerable than others, highlights community-generated ideas about vulnerability reduction, and pinpoints a range of additional vulnerability reduction actions. Tsunami survivors most consistently identified the 'most vulnerable' community sub-populations as women, children, the elderly, foreigners, and the poor. In Khao Lak, however, respondents added 'Burmese migrants' to this list, whereas in Koh Phi Phi Don, they added 'Thai Muslims'. Results suggest that the two case study communities, both small, coastal, tourism-dominated communities no more than 100 kilometres apart, have differing vulnerable sub-groups and environmental vulnerabilities, requiring different post-disaster vulnerability reduction efforts.  相似文献   
969.
Diazinon Fate and Toxicity in the Tajan River (Iran) Ecosystem   总被引:1,自引:0,他引:1  
Abstract This study surveyed the behavior of diazinon pesticide in the water column of the Tajan River and its potential effects on river biota. The Tajan River is located on the southern basin of the Caspian Sea in Iran and diazinon enters the river from rice fields almost every year between the months of June and October. The sampling plan of flowing water was plotted in a 3-week period on five sites along the river and also at the end of tributaries. Samples were collected seven times during a 6-month period; they were analyzed for diazinon residues and some physicochemical characteristics. Total diazinon concentration range was between 0.01 and 46.99?μg/L in sampling stations. The calibrated AQUATOX model was applied to simulate fate processes and ecotoxicity of diazinon in the Tajan River. The model demonstrated that the diazinon residues in the Tajan River reacted to three major degradation processes (microbial, hydrolysis, and photolysis) and sedimentation; however, the river discharge played the m...  相似文献   
970.
魏宁  刘胜男  魏凤  李小春 《环境科学》2023,44(12):6621-6629
中国水泥行业面临巨大的碳达峰与碳中和压力.CO2捕集利用与封存(CCUS)技术是能够实现化石资源低碳利用的碳减排技术.在中国水泥企业数据基础上,采用全流程CCUS系统模型(ITEAM-CCUS)评估CCUS的碳减排潜力对水泥企业碳中和非常重要.模型从源汇匹配距离、捕集率、CCUS技术和技术水平这4个方面设置了10种情景,完成了水泥行业的企业筛选、场地筛选、CCUS技术经济评估和源汇匹配,初步回答了水泥企业结合CCUS的封存场地、减排规模、成本范围和优先项目分布等关键问题.在250 km匹配距离、85%净捕集率、CO2-EWR技术和当前技术水平情景,44%的水泥企业可以利用CO2强化地下水开采(CO2-EWR)技术开展碳减排,累计年碳减排量为6.25亿t,平准化成本为290~1838元·t-1;具有全流程CO2-EWR早期示范优势的地区为新疆、内蒙古、宁夏、河南和河北等.水泥企业开展全流程CCUS项目技术可行,可以实现大规模CO2减排,低成本项目具有早期示范机会.研究结果可为水泥行业低碳发展和CCUS商业化部署提供定量参考.  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