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   18940篇
  免费   4902篇
  国内免费   28181篇
安全科学   1796篇
废物处理   789篇
环保管理   1598篇
综合类   33540篇
基础理论   3613篇
环境理论   4篇
污染及防治   7595篇
评价与监测   1799篇
社会与环境   535篇
灾害及防治   754篇
  2024年   30篇
  2023年   228篇
  2022年   569篇
  2021年   535篇
  2020年   1038篇
  2019年   2134篇
  2018年   2387篇
  2017年   2446篇
  2016年   2170篇
  2015年   2691篇
  2014年   3400篇
  2013年   3745篇
  2012年   3490篇
  2011年   3047篇
  2010年   2727篇
  2009年   2748篇
  2008年   2429篇
  2007年   2355篇
  2006年   1828篇
  2005年   1374篇
  2004年   1198篇
  2003年   1019篇
  2002年   878篇
  2001年   847篇
  2000年   994篇
  1999年   860篇
  1998年   683篇
  1997年   592篇
  1996年   615篇
  1995年   575篇
  1994年   395篇
  1993年   304篇
  1992年   361篇
  1991年   300篇
  1990年   261篇
  1989年   209篇
  1988年   149篇
  1987年   79篇
  1986年   77篇
  1985年   54篇
  1984年   55篇
  1983年   41篇
  1982年   45篇
  1981年   35篇
  1979年   4篇
  1978年   3篇
  1977年   2篇
  1974年   1篇
  1972年   6篇
  1971年   7篇
排序方式: 共有10000条查询结果,搜索用时 31 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.
Environmental Science and Pollution Research - A mechanical harvesting technology based on coupling flocculation with a rotary drum filter (RDF, 35-μm) was applied to remove cyanobacterial...  相似文献   
3.
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   
4.
Environmental Science and Pollution Research - Hydrothermal liquefaction (HTL) of biomass used HTL reaction under high temperature and pressure to produce bio-oil. This technology is considered as...  相似文献   
5.
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   
6.
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   
7.
ABSTRACT

In this study, a three-dimension (3D) computational model was proposed to investigate the flow and heat transfer characteristics of the intake grilles of two different fuel cell vehicles. The models of the intake grilles were constructed according to the actual sizes of two vehicles, namely, Roewe 950 and Toyota Mirai, considering the heat dissipation unit to simplify the heat transfer model of the vehicle. The results showed that relative to Roewe 950, Mirai intake air flow rate was approximately 10% higher, the heat transfer capacity was approximately 7% higher, and the intake grille area was larger. The coolant outlet temperature of Mirai was lower than that of Roewe 950, which was beneficial for the long term and stable operation of a fuel cell. This comparative study provided guidance for the intake grille and radiator design of fuel cell vehicles. The only difference between fuel cell vehicles on the market and conventional vehicles was that in the former, the internal combustion engine was replaced with a fuel cell stack, which had insufficient heat transfer capacity because of the reducing temperature difference. Increasing the intake grille area and the heat exchange capacity of the radiator were the key issues for the development of fuel cell vehicles. In this study, an optimal window opening angle of the radiator fin of 23° provided a maximal heat transfer coefficient.  相似文献   
8.
Environmental Science and Pollution Research - China is the most populous country in the world, and the pollution caused by the excessive population should not be underestimated. In recent years,...  相似文献   
9.
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   
10.
At present, internal rural tourism is at the stage of upgrading and renewing, and ecotourism has been considered to be the main direction. This paper discussed the concepts and criteria of rural tourism and ecotourism, analyzed a typical case of Nongke Village of Chengdu City-being considered to be the first rural tourism site in China, went deep into the problems of the contents and criteria of the development of rural ecotourism, and tried to probe into the principles of the development of rural ecotourism both theoretically and practically so as to understand the rules of the development of rural ecotourism .  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