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   1885篇
  免费   127篇
  国内免费   253篇
安全科学   244篇
废物处理   17篇
环保管理   397篇
综合类   836篇
基础理论   147篇
污染及防治   104篇
评价与监测   78篇
社会与环境   340篇
灾害及防治   102篇
  2024年   6篇
  2023年   20篇
  2022年   41篇
  2021年   64篇
  2020年   43篇
  2019年   42篇
  2018年   56篇
  2017年   74篇
  2016年   70篇
  2015年   90篇
  2014年   67篇
  2013年   154篇
  2012年   127篇
  2011年   154篇
  2010年   105篇
  2009年   104篇
  2008年   83篇
  2007年   153篇
  2006年   117篇
  2005年   86篇
  2004年   80篇
  2003年   73篇
  2002年   75篇
  2001年   42篇
  2000年   61篇
  1999年   46篇
  1998年   31篇
  1997年   27篇
  1996年   21篇
  1995年   22篇
  1994年   32篇
  1993年   11篇
  1992年   10篇
  1991年   5篇
  1990年   12篇
  1989年   6篇
  1988年   6篇
  1987年   9篇
  1986年   3篇
  1985年   3篇
  1983年   2篇
  1982年   3篇
  1980年   7篇
  1979年   4篇
  1978年   3篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1972年   3篇
  1971年   2篇
排序方式: 共有2265条查询结果,搜索用时 15 毫秒
971.
Failure mode and effect analysis (FMEA) is the most important method used by production companies to identify potential risks regarding occupational and health hazards and environmental hazards. This method is also useful in defining preventive actions to reduce the effects of these risks. Detergent production companies continually encounter many occupational and health hazards and environmental hazards, the management and reduction of which requires complex assessment in real‐world applications. This paper presents a framework for application of FMEA for managing and ranking identified risks in detergent production companies. A case study is presented to show the application of an FMEA to investigate the results of its application and the outcomes from the analysis. A risk priority number (RPN) is proposed for each distinct risk. The application of FMEA in the detergent production company resulted in grouping the RPN of the identified risks into four different categories. The main corrective actions, which are determined to reduce the RPNs, are presented in this paper. Improving the RPN of the main risks is observed after executing the corrective actions.  相似文献   
972.
论述了冶炼烟气中含硒量特别是气态硒检测的方法,并对有效选用采样仪器,抽气体积,吸收液等关键问题做了具有针对性的分析探讨。  相似文献   
973.
Human health is greatly affected by inadequate access to sufficient and safe drinking water, especially in low and middle-income countries. Drinking water governance improvements may be one way to better drinking water quality. Over the past decade, many projects and international organizations have been dedicated to water governance; however, water governance in the drinking water sector is understudied and how to improve water governance remains unclear. We analyze drinking water governance challenges in three countries – Brazil, Ecuador, and Malawi – as perceived by government, service providers, and civil society organizations. A mixed methods approach was used: a clustering model was used for country selection and qualitative semi-structured interviews were used with direct observation in data collection. The clustering model integrated political, economic, social and environmental variables that impact water sector performance, to group countries. Brazil, Ecuador and Malawi were selected with the model so as to represent the diversity of the clusters. This comparative case study is important because similar challenges are identified in the drinking water sectors of each country; while, the countries represent diverse socio-economic and political contexts, and the case selection process provides generalizability to our results. We find that access to safe water could be improved if certain water governance challenges were addressed: coordination and data sharing between ministries that deal with drinking water services; monitoring and enforcement of water quality laws; and sufficient technical capacity to improve administrative and technical management of water services at the local level. From an analysis of our field research, we also developed a conceptual framework that identifies policy levers that could be used to influence governance of drinking water quality on national and sub-national levels, and the relationships between these levers.  相似文献   
974.
本文对川南旅游开发的导向、人才与资金准备及产业协调等问题进行了探讨,提出了川南旅游资源地域开发的时空模式,建议加强重点景区的资源保护与开发建设,提倡生态旅游  相似文献   
975.
蒸散量测定与估算方法的对比研究   总被引:34,自引:1,他引:33  
以涡度相关法的实测资料为标准,对波文比-能量平衡法、空气动力学法、Penman-Monteith模型、Shuttleworth-Wallace模型进行对比研究,并分析了各种方法的精度和灵敏度。结果表明:Penman-Monteith模型和波文比-能量平衡法的精度最高,Shuttleworth-Wallace模型和空气动力学法的精度较差。Penman-Monteith模型的稳定性较好,波文比-能量平衡法受Δe和ΔT观测精度的影响大,风温湿观测高度以及下垫面是否均一对空气动力学法影响较大,Shuttleworth-Wallace模型对各类阻抗较为敏感。  相似文献   
976.
贵阳市二氧化硫和酸沉降污染来源及控制战略   总被引:1,自引:0,他引:1  
采用一个综合区域空气质量/酸沉降模型,对典型气象条件下贵阳市、贵州省和整个西南地区不同尺度的SO2控制情景进行模拟.数值模拟结果表明,贵州全省大点源排放是贵阳市酸沉降的最主要贡献者;贵阳市内的大电厂对贵阳市的SO2污染有一定的贡献,但对硫酸盐浓度和酸沉降贡献则较小.在此基础上,提出了贵阳市酸沉降和SO2污染的控制对策.   相似文献   
977.
复合配方絮凝剂处理炼油厂含油废水的研究   总被引:3,自引:1,他引:2  
LKM型絮凝剂具有破乳能力强、水溶性好、使用方便和储存稳定的特点 ,其复合制剂的除油效果更好。现场工业试验证明 :在除油率大致相同的情况下 ,其投加量为聚合氯化铝的 1 2至 1 5,浮渣生成量少 ,易于处置和利用 ,可作为聚合氯化铝的换代产品在含油废水处理中使用。  相似文献   
978.
西部大开发中的生态安全问题   总被引:12,自引:0,他引:12       下载免费PDF全文
正确处理区域发展与生态安全是西部开发战略的关键。以可持续发展为目标的区域空间结构理论 ,分析了在新一轮科技革命和产业革命的新形势下推动区域发展和区域空间结构演变的决定性因素 ,以及实行效益原则与社会公平原则相统一的必要性 ,从中引出西部大开发中确保生态安全的极端重要性。并就实现区域发展与生态安全的双赢目标所必须建立的能力体系和制度体系提出了建议。   相似文献   
979.
Total diet study (TDS) samples of 14 food groups from 16 locations in Japan, collected in 1999 and 2000, were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) to estimate the update of daily intake of these contaminants from food. The mean daily intake of toxic equivalency (TEQ) for an adult weighing 50 kg, calculated at non-detected isomer concentrations equal to zero (ND=0), was estimated to be 2.25 pg TEQ/kg b.w./day. When non-detected isomer concentrations are assumed to be equal to half of the limits of detection (ND=1/2 LOD), the mean daily intake was estimated to be 3.22 pg TEQ/kg b.w./day. These values were below the tolerable daily intake (TDI) of 4 pg TEQ/kg b.w. for PCDD/Fs and dioxin-like PCBs set in Japan. In both the estimates, the mean daily intakes were highest from fish and shellfish (76.9% at ND=0 and 53.9% at ND=1/2 LOD of the total TEQs), followed by those from meat and eggs (15.5% at ND=0 and 11.7% at ND=1/2 LOD of the total TEQs). Congener specific data revealed that these total TEQ levels were dominated by 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF and 3,3,4,4,5-PeCB in each case (71.7% at ND=0 and 63.1% at ND=1/2 LOD of the total TEQs). The dioxin-like PCBs (non-ortho and mono-ortho PCBs) accounted for about 50% of these total TEQs. These data will be very useful in the risk assessment of PCDD/Fs and dioxin-like PCBs from food in Japan.  相似文献   
980.
室内环境污染研究进展   总被引:1,自引:0,他引:1  
介绍了室内环境污染问题的由来及危害、研究对象及内容 ,并对国内外在室内环境这一新兴学科领域所开展的研究工作进行了综述 ,同时指出了我国进行室内环境污染系统研究的必要性。  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