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   234篇
  免费   9篇
  国内免费   71篇
安全科学   10篇
废物处理   22篇
环保管理   21篇
综合类   132篇
基础理论   41篇
污染及防治   68篇
评价与监测   11篇
社会与环境   5篇
灾害及防治   4篇
  2023年   4篇
  2022年   6篇
  2021年   9篇
  2020年   3篇
  2019年   8篇
  2018年   5篇
  2017年   4篇
  2016年   9篇
  2015年   21篇
  2014年   16篇
  2013年   23篇
  2012年   20篇
  2011年   19篇
  2010年   9篇
  2009年   12篇
  2008年   17篇
  2007年   20篇
  2006年   15篇
  2005年   8篇
  2004年   10篇
  2003年   6篇
  2002年   7篇
  2001年   5篇
  2000年   14篇
  1999年   11篇
  1998年   3篇
  1997年   4篇
  1996年   2篇
  1995年   7篇
  1994年   6篇
  1993年   1篇
  1990年   2篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1984年   2篇
  1982年   2篇
排序方式: 共有314条查询结果,搜索用时 0 毫秒
231.
农业生态工程中的价值流分析   总被引:3,自引:1,他引:3  
卞有生 《环境科学》1999,20(4):104-107
阐述了价值流研究分析对建议农业生态工程的意义,及对提高生产力的作用,并通过胜利油田生态农场1990年价值流的分析,比较了生态农场价值产投比,产值优势度,货币效益,阐述了管理对价值流的控制作用。  相似文献   
232.
概述了高梯度磁分离技术在燃煤脱硫除灰方面的应用与研究进展,以及超导磁分离技术在燃煤脱硫方面的研究,并展望了超导磁分离技术在环境保护中的应用前景。  相似文献   
233.
The objective of this work was to develop a novel wet-scrubbing process using Fe(VI) for the simultaneous removal of gaseous NO and SO(2). The oxidation of SO(2) and NO with Fe(VI) was studied in aqueous solution at alkaline pH (9.0-11.0). A stoichiometric molar ratio for NO and SO(2) oxidation with Fe(VI) was determined to be nearly 3.0. Sulfate and nitrate was identified as final products by ion chromatography from the reaction at pH 9.0-11.0. The feasibility of simultaneous removal of multiple gas pollutants with the continuous feeding of ferrate in lab-scale was investigated from the view of industrial application. It was found that the removal efficiency of NO and SO(2) was enhanced with the increase of Fe(VI) concentration, more than 90% NO removal efficiency and 100% SO(2) removal efficiency were achieved by wet-scrubbing process using Fe(VI) at room temperature and ambient atmosphere. The results demonstrate that Fe(VI) could be an effective wet-scrubbing agent for the simultaneous removal of NO and SO(2).  相似文献   
234.
Road-deposited sediment (RDS) is an important environmental medium for impacting the characteristics of pollutants in stormwater runoff; it is of critical importance to investigate the water quality of urban environments. The paper develops a rainfall simulator as an important research tool to ensure homogeneity and reduce the large number of variables that are usually inherent to urban water quality research. The rainfall simulator was used to experiment runoff samples from typical residential and traffic areas in the Zhenjiang. The data show that land use is one of the major factors contributing to the difference in the pollutants concentration in the RDS. The maximum mean EMC for TN, TDN, TP, and TDP at residential area was 5.52, 3.07, 1.65, and 0.36 mg/L, respectively. The intense traffic area displayed the highest metal concentrations. Concentrations of runoff pollutants varied greatly with land use and storm characteristics. The correlation of pollutant concentrations with runoff times was another predominant phenomenon. Peaks in pollutants concentration occurred at 1 and 10 min during the whole storm event. A concentration peak that correlates with a peak in runoff flowrate correlates with rainfall intensity. The pollutant loadings (kilograms per hectare) in the Zhenjiang were 11.39 and 55.28 for COD, 8.42 and 57.48 for SS, 0.11 and 0.88 for TN, 0.02 and 0.14 for TP, 0.02 and 0.09 for Zn, and 0.01 and 0.04 for Pb. The higher rainfall contribute to the higher pollutant loading at the residential and intense traffic areas, as a result of the pollutant loadings direct dependence on rainfall intensity. The results confirmed that the rainfall simulator is a reliable tool for urban water quality research and can be used to simulate pollutant wash-off. These findings provide invaluable information for the development of appropriate management strategies to decrease nonpoint source contamination loading to the water environment in urban areas.  相似文献   
235.
An understanding of road-deposited sediment (RDS) characteristics on an impervious surface is essential to estimate pollutant washoff characteristics and to minimise the impacts of pollutants on the water environment. A total of 62 RDS samples were collected from four different land-use types (commercial, residential, intense traffic and riverside park) in Zhenjiang City, China. The samples were fractionated into seven grain-size classes and analysed for particle size distribution and concentrations of pollutants. The samples are found to consist predominantly of fine particles (60–80%, <250 μm). The maximum mean concentrations of zinc, lead and copper were 686.93, 589.19 and 158.16 mg/kg, respectively, with the highest metal concentrations found in samples from the intense traffic area. The maximum mean contents of organic matter (12.55%), nitrogen (6.31 mg/g) and phosphorus (5.15 mg/g) were found in samples from the commercial area. The concentrations of heavy metals were highest in the smallest particle size fraction analysed (63 μm). The organic matter and nitrogen content generally increased with decreasing particle sizes in the <500-μm particle size range. The results also revealed that most of the total nitrogen (TN) is attached to the finer sediments and that to effectively reduce TN loads in particulates, treatment facilities must be able to remove the finer particles (down to 125 μm for TN).  相似文献   
236.
Based on the theory of ecological footprint this paper analyzed the ecological economic system in Funing County in the view of demands of economic system to natural resource and supply of ecosystem for natural resources. It was proposed that the concept of ecological deficit (ecological remainder) per ten thousands yuan GDP be used to evaluate development of ecological economic system. With a synthesis appraisement to the ecological economic system using entire-array-polygon method combined with Ulanowicz development ability and with ecological deficit (ecological remainder) per ten thousands yuan GDP, it provids a theoretical base for reconstructing and managing of demonstration eco-region.  相似文献   
237.
漓江流域红壤侵蚀区植被演替与复合农林试验   总被引:1,自引:0,他引:1  
漓江季节性的干旱和洪涝并存成为地方政府、有关专家和旅游行业密切关注的环境问题,漓江流域的环境建设尤其是上游森林植被恢复,成为生态治理重点内容。漓江上游红壤区植被类型主要包括针叶林、阔叶林、竹林、灌丛和草丛,植被的水分特征差异较大,植被的生态调节、水源涵养功能各异。在漓江上游红壤区开展4种模式的植被恢复和复合农林试验示范,3年的试验表明,乡土常绿阔叶树适应性强、有效保持水土,果林经济效益显著、但生态功能较差,木本药材林具有较好的生态功能和潜在的经济效益。通过调查和试验示范,提出亚热带红壤退化山地农林经营的植物种类和复合模式,对漓江流域水资源调控和水土流失治理提出建议和对策。  相似文献   
238.
以鼎湖山3个南亚热带森林演替典型阶段生态系统为对象,采用我国《森林生态系统服务功能评估规范》(LY/T 1721—2008)标准化计算公式与服务价格,量化揭示南亚热带森林生态系统演替过程中生态系统服务功能价值动态。结果表明:随着演替的进行,南亚热带森林生态系统服务功能总价值不断增大;但各分项服务功能价值则表现出不同的动态规律与变化幅度,从而使得森林生态系统服务结构呈现非线性演化特征。在南亚热带森林生态系统演替的早期阶段,生态系统服务价值的最大组分是涵养水源的功能价值,而中、后期则是保育土壤。人工林营造可以有效增强区域生态系统的水源涵养能力,而保育演替中、后期森林则对于大气CO2收和土壤保育而言尤为重要。  相似文献   
239.
附壁式爬模法在烟囱施工的安装、提升操作、高空拆除过程中的安全技术措施。  相似文献   
240.
燃气火焰中热力型NOx以NO为主,以NO为主,燃烧温度对NO生成起决定作用,空气系数也主要通过改变燃烧温度影响NOx生成。燃烧温度大于1800K时,有较多NO生成。降低燃烧温度与保持高效燃烧相协调是控制NOx生成的关键。  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