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   516篇
  免费   84篇
  国内免费   263篇
安全科学   89篇
废物处理   23篇
环保管理   15篇
综合类   465篇
基础理论   144篇
污染及防治   78篇
评价与监测   3篇
社会与环境   4篇
灾害及防治   42篇
  2024年   2篇
  2023年   12篇
  2022年   13篇
  2021年   14篇
  2020年   13篇
  2019年   20篇
  2018年   26篇
  2017年   21篇
  2016年   29篇
  2015年   45篇
  2014年   33篇
  2013年   71篇
  2012年   56篇
  2011年   75篇
  2010年   55篇
  2009年   48篇
  2008年   50篇
  2007年   54篇
  2006年   44篇
  2005年   40篇
  2004年   26篇
  2003年   32篇
  2002年   20篇
  2001年   6篇
  2000年   17篇
  1999年   12篇
  1998年   4篇
  1997年   2篇
  1996年   3篇
  1995年   7篇
  1994年   4篇
  1993年   1篇
  1992年   4篇
  1989年   2篇
  1988年   1篇
  1983年   1篇
排序方式: 共有863条查询结果,搜索用时 15 毫秒
861.
• Urban aerosols harbour diverse bacterial communities in Shanghai. • The functional groups were associated with nitrogen, carbon, and sulfur cycling. • Temperature, SO2, and wind speed were key drivers for the bacterial community. Airborne bacteria play key roles in terrestrial and marine ecosystems and human health, yet our understanding of bacterial communities and their response to the environmental variables lags significantly behind that of other components of PM2.5. Here, atmospheric fine particles obtained from urban and suburb Shanghai were analyzed by using the qPCR and Illumina Miseq sequencing. The bacteria with an average concentration of 2.12 × 103 cells/m3, were dominated by Sphingomonas, Curvibacter, Acinetobacter, Bradyrhizobium, Methylobacterium, Halomonas, Aliihoeflea, and Phyllobacterium, which were related to the nitrogen, carbon, sulfur cycling and human health risk. Our results provide a global survey of bacterial community across urban, suburb, and high-altitude sites. In Shanghai (China), urban PM2.5 harbour more diverse and dynamic bacterial populations than that in the suburb. The structural equation model explained about 27%, 41%, and 20%–78% of the variance found in bacteria diversity, concentration, and discrepant genera among urban and suburb sites. This work furthered the knowledge of diverse bacteria in a coastal Megacity in the Yangtze river delta and emphasized the potential impact of environmental variables on bacterial community structure.  相似文献   
862.
罗路云  金德才  王殿东  陈昂  张德咏  曾军  匡炜  张卓  刘勇 《环境科学》2021,42(10):4988-4997
稻田重金属污染每年造成水稻产量的巨大损失,重金属污染问题日益受到人们的关注.因此,了解不同镉污染水平下水稻土微生态及理化性质的变化具有重要意义.本研究通过16S测序技术探讨稻田土壤光合细菌群落对不同镉污染水平的响应.结果表明,随着镉污染程度升高,pH值、总镉和有效镉含量逐渐降低.高镉组、中镉组和低镉组的土壤α多样性差异较小,富集的光合细菌种群具有显著差异,光合细菌群落之间也均具有显著差异.高镉组光合细菌物种之间有效连接明显多于中镉和低镉组,连接更紧密且密度更高.碱性氮、pH、有效磷、有效钾、总氮、总磷、有机质、总镉和有效镉是影响光合细菌群落的重要因素,与光合细菌群落显著相关,解释了59.90%的光合细菌群落变异,其中有效镉含量与Methylorubrum populiMethylorubrum extorquensMethylobacterium sp.Leaf125和Rhodopseudomonas sp.AAP120显著正相关(R>0.05,P<0.05).本研究对了解镉污染对稻田土壤特定功能微生物种群的影响具有重要意义.  相似文献   
863.
In the deep high stress coal and rock mass, the efficiency of the ordinary blasting method is constantly affected by the high pressure. This study investigates the shaped blasting technology with increased blasting efficiency, develops a mechanical model for coal crack expansion during shaped blasting, and examines the force-energy action of energy-gathering jets during coal splitting. The established model was combined with experiments and simulations to reveal the damage and evolution of cracks in coal and rock masses. Experiments demonstrate that shaped blasting can create an energy-gathering jet that causes a directional fracture in the test block. The peak of compressive strain in the energy-gathering direction is 1.12 times greater than that of ordinary blasting, and the static action period of the explosive gas is prolonged by 1.3 μs according to the stress curve. Moreover, the peak pressure strain increased 3.2 times, and the pull strain peak increased 3.92 times. The damage amount was represented by the resistivity and ultrasonic wave speed, and shaped blasting causes 1.2 and 1.5 times greater damage than ordinary blasting. The research results provide technical methods for safe and rapid penetration blasting in deep high-ground stressed coal mines.  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