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   3173篇
  免费   26篇
  国内免费   38篇
安全科学   84篇
废物处理   174篇
环保管理   307篇
综合类   525篇
基础理论   660篇
环境理论   3篇
污染及防治   956篇
评价与监测   294篇
社会与环境   212篇
灾害及防治   22篇
  2023年   36篇
  2022年   120篇
  2021年   137篇
  2020年   70篇
  2019年   58篇
  2018年   123篇
  2017年   121篇
  2016年   148篇
  2015年   94篇
  2014年   150篇
  2013年   209篇
  2012年   150篇
  2011年   189篇
  2010年   140篇
  2009年   128篇
  2008年   135篇
  2007年   129篇
  2006年   84篇
  2005年   131篇
  2004年   166篇
  2003年   153篇
  2002年   107篇
  2001年   84篇
  2000年   36篇
  1999年   35篇
  1998年   16篇
  1997年   26篇
  1996年   19篇
  1995年   23篇
  1994年   19篇
  1993年   8篇
  1992年   11篇
  1991年   16篇
  1990年   9篇
  1989年   12篇
  1988年   5篇
  1987年   10篇
  1986年   8篇
  1985年   11篇
  1984年   10篇
  1983年   11篇
  1982年   6篇
  1981年   8篇
  1979年   9篇
  1978年   4篇
  1970年   3篇
  1969年   3篇
  1966年   3篇
  1964年   4篇
  1961年   3篇
排序方式: 共有3237条查询结果,搜索用时 15 毫秒
961.
962.
In the evaluation of potentially adverse effects oforganic chemicals such as pesticides on theenvironment the atmosphere may play an important role.After its release to the atmosphere the chemical willbe transported/dispersed in the atmosphere and finallyit will be removed either by atmospheric-chemicaldestruction or by deposition to the underlying soil orsurface water. In a risk assessment decision supportsystem both ambient concentrations and depositionfluxes must be known to evaluate the risk of directexposure (inhalation) or the risk of soil and watercontamination caused by deposition. This paperdiscusses the use of atmospheric dispersion models insuch risk assessment decision support systems.  相似文献   
963.
城市空气质量的管理   总被引:3,自引:0,他引:3  
根据“城市空气质量管理,欧盟和中国的实践与经验”国际会专家的发言,整理出有关中国城市空气质量管理的10条建议,城市空气质量管理工作要加强其有生的评估,环保立法 和标准工作要体现先进性,发挥引导作用,城市空气质量管理要有科学研究的支持增强科学性;城市空气质量管理要有区域性的观点,城市质量管理要有前瞻性;城市质量要贯彻可持续发展战略,环保部门负责做好;空气质量管理,积极参与空气的污染治理,深化空气质量  相似文献   
964.
石墨炉原子吸收法在环境样品测定中的应用   总被引:3,自引:3,他引:0  
评述了石墨炉原子吸收光谱法在环境样品测定中的应用 ,内容包括装置与技术、水与废水、土壤与底质 ,以及大气与废气  相似文献   
965.
Remote sensing of aquatic vegetation: theory and applications   总被引:2,自引:0,他引:2  
Aquatic vegetation is an important component of wetland and coastal ecosystems, playing a key role in the ecological functions of these environments. Surveys of macrophyte communities are commonly hindered by logistic problems, and remote sensing represents a powerful alternative, allowing comprehensive assessment and monitoring. Also, many vegetation characteristics can be estimated from reflectance measurements, such as species composition, vegetation structure, biomass, and plant physiological parameters. However, proper use of these methods requires an understanding of the physical processes behind the interaction between electromagnetic radiation and vegetation, and remote sensing of aquatic plants have some particular difficulties that have to be properly addressed in order to obtain successful results. The present paper reviews the theoretical background and possible applications of remote sensing techniques to the study of aquatic vegetation.  相似文献   
966.
This paper reports the using of neural networks for water quality analysis in a tropical urban stream before (2002) and after sewerage building and the completion of point-source control-based sanitation program (2003). Mathematical modeling divided water quality data in two categories: (a) input of some in situ water quality variables (temperature, pH, O2 concentration, O2 saturation and electrical conductivity) and (b) water chemical composition (N-NO2(-); N-NO3(-); N-NH4(+) Total-N; P-PO4(3-); K+; Ca2+; Mg+2; Cu2+; Zn2+ and Fe+3) as the output from tested models. Stream water data come from fortnightly sampling in five points along the Ipanema stream (Southeast Brazil, Minas Gerais state) plus two points downstream and upstream Ipanema discharge into Doce River. Once the best models are consistent with variables behavior we suggest that neural networking shows potential as a methodology to enhance guidelines for urban streams restoration, conservation and management.  相似文献   
967.
The Vicuña oil tanker exploded in Paranaguá Bay (South of Brazil), during methanol unloading operations in front of Paranaguá Harbour, on November 15th, 2004, releasing a large amount of bunker oil and methanol. Two weeks after the accident, the acute effects of the Vicuña Oil Spill (VOS) were evaluated in the demersal catfish Cathorops spixii, comparing a contaminated (at the spill site) and a reference site inside the Bay. Data were compared to previous measurements, taken before the accident, in the same species, from the same sites. The physiological biomarkers were the ones that best reflected acute effects of the spill: plasma osmolality, chloride, calcium, magnesium, and potassium. Morphological (liver and gill histopathology) and genetic (piscine micronucleus and DNA strand breaks) biomarkers revealed that damage was already present in fishes from both reference and contaminated sites inside the Bay. Thus, the reference site is not devoid of contamination, as water circulation tends to spread the contaminants released into other areas of the Bay. Acute field surveys of oil spill effects in harbour areas with a long history of contamination should thus be viewed with caution, and whenever possible previous evaluations should be considered for proper appraisal of biomarker sensitivity, especially in mobile bioindicators such as fish.  相似文献   
968.
An essential step in the development of products based on biotechnology is an assessment of their potential economic impacts and safety, including an evaluation of the potential impact of transgenic crops and practices related to their cultivation on the environment and human or animal health. The purpose of this paper is to provide an assessment method to evaluate the impact of biotechnologies that uses quantifiable parameters and allows a comparative analysis between conventional technology and technologies using GMOs. This paper introduces a method to perform an impact analysis associated with the commercial release and use of genetically modified plants, the Assessment System GMP Method. The assessment is performed through indicators that are arranged according to their dimension criterion likewise: environmental, economic, social, capability and institutional approach. To perform an accurate evaluation of the GMP specific indicators related to genetic modification are grouped in common fields: genetic insert features, GM plant features, gene flow, food/feed field, introduction of the GMP, unexpected occurrences and specific indicators. The novelty is the possibility to include specific parameters to the biotechnology under assessment. In this case by case analysis the factors of moderation and the indexes are parameterized to perform an available assessment.  相似文献   
969.
970.
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