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   20908篇
  免费   484篇
  国内免费   2303篇
安全科学   815篇
废物处理   824篇
环保管理   2568篇
综合类   6796篇
基础理论   4637篇
环境理论   10篇
污染及防治   6010篇
评价与监测   1013篇
社会与环境   688篇
灾害及防治   334篇
  2023年   160篇
  2022年   361篇
  2021年   341篇
  2020年   258篇
  2019年   277篇
  2018年   408篇
  2017年   415篇
  2016年   480篇
  2015年   537篇
  2014年   681篇
  2013年   1745篇
  2012年   816篇
  2011年   994篇
  2010年   788篇
  2009年   869篇
  2008年   917篇
  2007年   910篇
  2006年   819篇
  2005年   616篇
  2004年   602篇
  2003年   668篇
  2002年   590篇
  2001年   803篇
  2000年   589篇
  1999年   423篇
  1998年   340篇
  1997年   303篇
  1996年   317篇
  1995年   333篇
  1994年   339篇
  1993年   285篇
  1992年   277篇
  1991年   258篇
  1990年   273篇
  1989年   247篇
  1988年   197篇
  1987年   189篇
  1986年   176篇
  1985年   187篇
  1984年   168篇
  1983年   186篇
  1982年   185篇
  1981年   178篇
  1980年   159篇
  1979年   156篇
  1978年   154篇
  1977年   136篇
  1976年   141篇
  1974年   148篇
  1972年   134篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Environmental Science and Pollution Research - The existing literature on the environmental Kuznets curve (EKC) fails to investigate the spatial attribute of the “pollution halo” effect...  相似文献   
2.
Huang  Ying  Jiang  Qiongji  Yu  Xubiao  Gan  Huihui  Zhu  Xia  Fan  Siyi  Su  Yan  Xu  Zhirui  He  Cunrui 《Environmental science and pollution research international》2021,28(37):51251-51264
Environmental Science and Pollution Research - Trace copper ion (Cu(II)) in water and wastewater can trigger peroxymonosulfate (PMS) activation to oxidize organic compounds, but it only works under...  相似文献   
3.
Environmental Science and Pollution Research - The impact of high concentrations of air pollution on COVID-19 has been a major air quality and life safety issue in recent studies. This study aimed...  相似文献   
4.
Yan  Mi  He  Lei  Prabowo  Bayu  Fang  Zhumin  Lin  Jie  Xu  Zhang  Hu  Yanjun 《Journal of Material Cycles and Waste Management》2018,20(3):1594-1604
Journal of Material Cycles and Waste Management - Efforts to improve the performance of hydrothermal treatment (HT) in producing high-quality solid fuel from sewage sludge were carried out by...  相似文献   
5.
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   
6.
7.
8.
The quantitative relationship between the median effective concentration (EC50) of organic chemicals to Daphnia magna and the number of molecular fragments was investigated based on experimental EC50 values for 217 chemicals derived from the literature. A fragment constant model was developed based on a multivariate linear regression between the number of fragments and the logarithmically transformed reciprocal values of EC50. Functional correction factors were introduced into the model. The model was verified using an independent set of randomly selected data. The mean residual of the final model was 0.4 log-units. The robustness of the model was discussed based on the results of three jackknife tests.  相似文献   
9.
10.
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