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   21057篇
  免费   188篇
  国内免费   212篇
安全科学   570篇
废物处理   1026篇
环保管理   2610篇
综合类   2740篇
基础理论   5446篇
环境理论   4篇
污染及防治   5761篇
评价与监测   1697篇
社会与环境   1480篇
灾害及防治   123篇
  2023年   95篇
  2022年   219篇
  2021年   220篇
  2020年   147篇
  2019年   181篇
  2018年   335篇
  2017年   336篇
  2016年   536篇
  2015年   376篇
  2014年   591篇
  2013年   1831篇
  2012年   689篇
  2011年   900篇
  2010年   824篇
  2009年   817篇
  2008年   927篇
  2007年   1013篇
  2006年   911篇
  2005年   732篇
  2004年   743篇
  2003年   740篇
  2002年   692篇
  2001年   924篇
  2000年   641篇
  1999年   402篇
  1998年   280篇
  1997年   254篇
  1996年   304篇
  1995年   278篇
  1994年   258篇
  1993年   240篇
  1992年   248篇
  1991年   214篇
  1990年   219篇
  1989年   225篇
  1988年   199篇
  1987年   167篇
  1986年   134篇
  1985年   148篇
  1984年   187篇
  1983年   166篇
  1982年   206篇
  1981年   152篇
  1980年   123篇
  1979年   157篇
  1978年   122篇
  1977年   110篇
  1976年   103篇
  1974年   95篇
  1973年   85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 - There is mixed evidence surrounding the relationship between tobacco use and COVID-19 infection/progression. The current study investigates beliefs...  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.
This article postulates strong endogenous relationships in lower income countries between institutional quality, financial development and sustained economic growth. These associations were investigated using the vector-error correction model (VECM) and Granger causality method for a sample of 79 countries from 2005 to 2022. The findings show that (1) these variables reinforce each other in the short run. (2) In the long run, both institutional quality and financial development can fuel economic growth. (3) The positive effect of institutional quality on economic growth is greater than that of financial development. Policy implications of these findings are that careful attention should be paid to co-development policies to enhance the institutional quality and the financial system in these economies. Policies should also consider economic growth strategies to enable sustainable economic growth rates.  相似文献   
4.
The Science of Nature - We present the first study that compares phenological variation in parasite load and inflammatory response in a lizard with asynchronous male and female gonadal cycles....  相似文献   
5.
6.
7.
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   
8.
9.
Journal of Material Cycles and Waste Management - The present research work focused on fabricating Biodegradable Plate (BD plate) composed of rice husk ash, bagasse and corn starch which is...  相似文献   
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