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   8142篇
  免费   73篇
  国内免费   190篇
安全科学   194篇
废物处理   501篇
环保管理   674篇
综合类   1120篇
基础理论   1815篇
环境理论   9篇
污染及防治   2868篇
评价与监测   683篇
社会与环境   514篇
灾害及防治   27篇
  2023年   69篇
  2022年   198篇
  2021年   200篇
  2020年   94篇
  2019年   122篇
  2018年   287篇
  2017年   210篇
  2016年   317篇
  2015年   224篇
  2014年   354篇
  2013年   714篇
  2012年   404篇
  2011年   520篇
  2010年   390篇
  2009年   352篇
  2008年   428篇
  2007年   479篇
  2006年   363篇
  2005年   307篇
  2004年   293篇
  2003年   267篇
  2002年   229篇
  2001年   321篇
  2000年   210篇
  1999年   106篇
  1998年   65篇
  1997年   67篇
  1996年   44篇
  1995年   67篇
  1994年   64篇
  1993年   51篇
  1992年   45篇
  1991年   47篇
  1990年   37篇
  1989年   38篇
  1988年   28篇
  1987年   20篇
  1986年   20篇
  1985年   21篇
  1984年   19篇
  1983年   26篇
  1982年   26篇
  1981年   17篇
  1980年   13篇
  1979年   15篇
  1978年   15篇
  1975年   13篇
  1972年   11篇
  1966年   11篇
  1958年   18篇
排序方式: 共有8405条查询结果,搜索用时 15 毫秒
1.
Environmental Science and Pollution Research - In this work, it was analyzed the behavior of three commercial activated carbons with different textural and chemical properties to adsorb...  相似文献   
2.
Environmental Science and Pollution Research - A current environmental problem is the uncontrolled use of various pesticides that are harmful to the environment and public health. The herbicide...  相似文献   
3.
Environmental Science and Pollution Research - Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of...  相似文献   
4.
Following the renewed effort at achieving a new green revolution for Africa, emphasis has been placed on modernizing smallholder agriculture through the deployment of improved inputs especially mechanized technologies. In Ghana, the government has in the last decade emphasized the provision of subsidized mechanized ploughing services to farmers alongside a rapidly growing private sector tractor service market. While mechanized technology adoption rates have increased rapidly, the deployment of these technologies has been without critical analysis of the impacts on production patterns and local agrarian systems. This paper examines the distributional impacts of agriculture mechanization on cropping patterns and farm sizes of smallholder farmers in northern Ghana using Geographic Information Systems (GIS) techniques, and semi-structured interviews with smallholder farmers (n=60). Specifically, comparative analysis of the field sizes and cropping patterns of participant farmers prior to and after the adoption of mechanized technologies was conducted. In-depth interviews were used to contextualize the experiences of smallholder farmers toward understanding how mechanization may be impacting traditional agriculture. Our findings reveal a mechanization paradox in which farm sizes are expanding, while cropping patterns are shifting away from traditional staple crops (pearl millet and sorghum bicolor) to market-oriented crops (maize, rice and groundnuts). This transition we argue, has adverse implications on the cultural dimension of food security, the organization of social life, and climate change adaptation. We recommend a retooling of the current agricultural policy focus to ensure context sensitivity for a more robust battle against food insecurity.  相似文献   
5.
Chlorpyrifos (O, O-diethyl O-3,5,6-trichloropyridin-2-yl phosphorothioate) and carbaryl (1-naphthyl methylcarbamate) are often applied concurrently as insecticides in food production. The aim of this study was to research their migration behavior in a real environment. We researched the leaching of both pesticides by setting up field lysimeters on a farm with the typical soil used in fruit production today. In order to analyze the variables involved in this process, we performed complementary adsorption studies, we performed complementary adsorption studies using batches and undisturbed soil laboratory columns for both compounds. The results for pesticide transport through the lysimeters showed that less than 1% of chlorpyrifos was recovered in the leachates, while almost 17% was recovered for carbaryl. Having completed the experiment in undisturbed laboratory columns, soil analysis showed that chlorpyrifos mainly remained in the first 5 cm, while carbaryl moved down to the lower sections. These results can be explained in view of the sorption coefficient values (KD) obtained in horizons A and B for chlorpyrifos (393 and 184 L kg?1) and carbaryl (3.1 and 4.2 L kg?1), respectively. By integrating the results obtained in the different approaches, we were able to characterize the percolation modes of these pesticides in the soil matrix, thus contributing to the sustainable use of resources.  相似文献   
6.
Biomethane production through biogas upgrading is a promising renewable energy for some industries which could be part of the equilibrium needed with fossil fuels consumption to achieve a sustainable society. This paper presents a comprehensive list of biogas upgrading technologies focused on carbon dioxide removal as well as recent advances reported by researcher with wide expertise in this topic. Additionally, an extensive costs–performance comparison among the technologies studied is discussed. Among the different alternatives, chemical scrubbing stood out to achieve high biomethane purities while cryogenic technologies proved to be effective against methane losses. Regarding the different costs, water scrubbing and membrane separation seem to be the most affordable techniques.  相似文献   
7.
Environmental Science and Pollution Research - The reduction of estrogen levels, as a result of menopause, is associated with the development of metabolic diseases caused by alterations in...  相似文献   
8.
9.
10.
A sensitivity analysis of a proposed parameterization of the stomatal conductance (g(s)) module of the European ozone deposition model (DO(3)SE) for Quercus ilex was performed. The performance of the model was tested against measured g(s) in the field at three sites in Spain. The best fit of the model was found for those sites, or during those periods, facing no or mild stress conditions, but a worse performance was found under severe drought or temperature stress, mostly occurring at continental sites. The best performance was obtained when both f(phen) and f(SWP) were included. A local parameterization accounting for the lower temperatures recorded in winter and the higher water shortage at the continental sites resulted in a better performance of the model. The overall results indicate that two different parameterizations of the model are needed, one for marine-influenced sites and another one for continental sites.  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