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   1027篇
  免费   22篇
  国内免费   18篇
安全科学   30篇
废物处理   81篇
环保管理   118篇
综合类   148篇
基础理论   221篇
环境理论   1篇
污染及防治   280篇
评价与监测   106篇
社会与环境   75篇
灾害及防治   7篇
  2023年   22篇
  2022年   70篇
  2021年   54篇
  2020年   32篇
  2019年   24篇
  2018年   62篇
  2017年   47篇
  2016年   60篇
  2015年   45篇
  2014年   59篇
  2013年   78篇
  2012年   48篇
  2011年   75篇
  2010年   36篇
  2009年   40篇
  2008年   44篇
  2007年   42篇
  2006年   36篇
  2005年   18篇
  2004年   30篇
  2003年   28篇
  2002年   25篇
  2001年   21篇
  2000年   12篇
  1999年   7篇
  1998年   2篇
  1997年   7篇
  1996年   6篇
  1995年   4篇
  1994年   1篇
  1993年   2篇
  1992年   8篇
  1991年   2篇
  1990年   1篇
  1988年   2篇
  1986年   3篇
  1985年   1篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1977年   1篇
  1974年   1篇
  1969年   1篇
  1964年   1篇
  1963年   1篇
  1961年   1篇
  1953年   1篇
  1951年   1篇
  1944年   1篇
排序方式: 共有1067条查询结果,搜索用时 19 毫秒
941.
942.
943.
浙江北部地区地势低洼,种粮易涝,严重制约当地农业的发展。2010年以来,作为湿地农业农作制度的创新,“水生作物 鱼类”种养结合模式在当地得到迅速发展。为了完善种养高效综合配套技术,在嘉兴市秀洲区3个农场开展了不同种养模式(藕 鱼和菱 鱼模式)的对比试验,对池塘水质、底质特征以及大气负氧离子浓度进行了分析。结果表明种养结合模式对池塘水质有一定改善作用。虽然养殖鱼类后水体有机污染有一定程度加重,但由于水生作物的吸收作用,使得水体氮磷含量明显降低。与菱 鱼模式相比,鱼塘种植莲藕后,对水质的改善效果更为明显。对底质的分析表明,鱼塘种植水生作物后,底泥中速效钾含量增加明显,尤其是在种植莲藕后。另外,由于施用化肥以及当年不收割引起的藕叶、茎杆等腐烂分解,使得藕 鱼模式池塘底泥中速效磷和总氮含量大幅增加,分别增加329.1% 和361.9%。对种养结合区域大气负氧离子浓度测定结果表明,种养结合开发利用有利于改善周边区域空气质量  相似文献   
944.
The occurrence of diseases in cultivars has caused significant losses in global food production. The advancement of nanobiotechnology makes it possible to obtain new products to be used in the control of pathogens in cultivars. Silver nanoparticles can be synthesized by microalgae and are widely known for their antimicrobial activity. In addition, the biomass produced in microalgal culture for the biosynthesis of the nanoparticles also demonstrates antimicrobial properties, as it can increase the antibacterial and antifungal potential of the silver nanoparticles. In this context, this article addresses the use of microalgae to biosynthesize silver nanoparticles simultaneously with biomass production. In addition, we demonstrate the antimicrobial potential of these nanomaterials, as well as of the microalgal biomass produced in biosynthesis, to use in the control of pathogens in agriculture.  相似文献   
945.
ABSTRACT

The exhaust emissions of 17 polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were investigated in two spark-ignition light-duty vehicles, one gasohol-fueled and a flexible-fuel one fueled with hydrated ethanol. Gasohol is a mixture of gasoline and 22% ethanol. The influence of fuel type and quality, lubricant oil type, and use of fuel additives on the formation of these compounds was tested using standardized U.S. Federal Test Procedure (FTP)-75 cycle tests. The sampling of the PCDD/Fs followed the recommendations of a modified U.S. Environmental Protection Agency (EPA) Method 23 (http://www.epa.gov/ttn/emc/promgate/m-23.pdf) and the analysis basically followed the U.S. EPA Method 8290 (http://www.epa.gov/osw/hazard/testmethods/sw846/pdfs/8290a.pdf). Results showed that emission factors of PCDD/Fs for the gasohol vehicle varied from undetected to 0.068 pg international toxic equivalency (I-TEQ) km?1 (average of 0.0294 pg I-TEQ km?1), whereas in the ethanol vehicle they varied from 0.004 to 0.157 pg (I-TEQ) km?1 (average of 0.031 pg I-TEQ km?1). In the gasohol-powered vehicle, the use of fuel additive diminished the emission of Octachlorodibenzo-p-dioxin (OCDD) significantly, whereas in the ethanol vehicle no significant associations were observed between the investigated variables and the emissions.

IMPLICATIONS The objective of this work was to analyze differences in emissions from a traditional fossil fuel (gasoline) and an alternative renewable fuel (ethanol from sugarcane), and the influence of fuel additives and lubricant oils on the formation of chlorinated dioxins and furans in spark-ignition light-duty gasohol and ethanol vehicles. Renewable fuels are very important in terms of climate change but the risk to the population's health must not increase. Thus the results of this work could help in the development of environmental impact studies as well as orienting policy-makers in formulating strategies for air pollution control.  相似文献   
946.
The exhaust emissions of 17 polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were investigated in two spark-ignition light-duty vehicles, one gasohol-fueled and a flexible-fuel one fueled with hydrated ethanol. Gasohol is a mixture of gasoline and 22% ethanol. The influence of fuel type and quality, lubricant oil type, and use of fuel additives on the formation of these compounds was tested using standardized U.S. Federal Test Procedure (FTP)-75 cycle tests. The sampling of the PCDD/Fs followed the recommendations of a modified U.S. Environmental Protection Agency (EPA) Method 23 (www.epa.gov/ttn/ emc/promgate/m-23.pdf) and the analysis basically followed the U.S. EPA Method 8290 (http://www.epa.gov/osw/ hazard/testmethods/sw846/pdfs/8290a.pdf). Results showed that emission factors of PCDD/Fs for the.gasohol vehicle varied from undetected to 0.068 pg international toxic equivalency (I-TEQ) km(-1) (average of 0.0294 pg I-TEQ km(-1)), whereas in the ethanol vehicle they varied from 0.004 to 0.157 pg (I-TEQ) km(-1) (average of 0.031 pg I-TEQ km(-1)). In the gasohol-powered vehicle, the use of fuel additive diminished the emission of Octachlorodibenzo-p-dioxin (OCDD) significantly, whereas in the ethanol vehicle no significant associations were observed between the investigated variables and the emissions.  相似文献   
947.
Valorization of winery waste vs. the costs of not recycling   总被引:1,自引:0,他引:1  
Wine production generates huge amounts of waste. Before the 1990s, the most economical option for waste removal was the payment of a disposal fee usually being of around 3000 Euros. However, in recent years the disposal fee and fines for unauthorized discharges have increased considerably, often reaching 30,000–40,000 Euros, and a prison sentence is sometimes also imposed. Some environmental friendly technologies have been proposed for the valorization of winery waste products. Fermentation of grape marc, trimming vine shoot or vinification lees has been reported to produce lactic acid, biosurfactants, xylitol, ethanol and other compounds. Furthermore, grape marc and seeds are rich in phenolic compounds, which have antioxidants properties, and vinasse contains tartaric acid that can be extracted and commercialized. Companies must therefore invest in new technologies to decrease the impact of agro-industrial residues on the environment and to establish new processes that will provide additional sources of income.  相似文献   
948.
Landfills receiving a mix of waste, including organics, have developed dramatically over the last 3-4 decades; from open dumps to engineered facilities with extensive controls on leachate and gas. The conventional municipal landfill will in most climates produce a highly contaminated leachate and a significant amount of landfill gas. Leachate controls may include bottom liners and leachate collection systems as well as leachate treatment prior to discharge to surface water. Gas controls may include oxidizing top covers, gas collection systems with flares or gas utilization systems for production of electricity and heat.The importance of leachate and gas control measures in reducing the overall environmental impact from a conventional landfill was assessed by life-cycle-assessment (LCA). The direct cost for the measures were also estimated providing a basis for assessing which measures are the most cost-effective in reducing the impact from a conventional landfill. This was done by modeling landfills ranging from a simple open dump to highly engineered conventional landfills with energy recovery in form of heat or electricity. The modeling was done in the waste LCA model EASEWASTE. The results showed drastic improvements for most impact categories. Global warming went from an impact of 0.1 person equivalent (PE) for the dump to −0.05 PE for the best design. Similar improvements were found for photochemical ozone formation (0.02 PE to 0.002 PE) and stratospheric ozone formation (0.04 PE to 0.001 PE).For the toxic and spoiled groundwater impact categories the trend is not as clear. The reason for this was that the load to the environment shifted as more technologies were used. For the dump landfill the main impacts were impacts for spoiled groundwater due to lack of leachate collection, 2.3 PE down to 0.4 PE when leachate is collected. However, at the same time, leachate collection causes a slight increase in eco-toxicity and human toxicity via water (0.007E to 0.013PE and 0.002 to 0.003 PE respectively). The reason for this is that even if the leachate is treated, slight amounts of contaminants are released through emissions of treated wastewater to surface waters.The largest environmental improvement with regard to the direct cost of the landfill was the capping and leachate treatment system. The capping, though very cheap to establish, gave a huge benefit in lowered impacts, the leachate collection system though expensive gave large benefits as well. The other gas measures were found to give further improvements, for a minor increase in cost.  相似文献   
949.
Environmental Science and Pollution Research - Agro-industrial waste biosorbents of arabica–coffee (WCA) and theobroma–cocoa (WCT) have been characterized and tested to remove Pb(II)...  相似文献   
950.
Environmental Science and Pollution Research - Energy demand has increased worldwide, and biomass burning is one of the solutions most used by industries, especially in countries that have a great...  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