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   800篇
  免费   190篇
  国内免费   55篇
安全科学   90篇
废物处理   45篇
环保管理   66篇
综合类   371篇
基础理论   131篇
污染及防治   249篇
评价与监测   35篇
社会与环境   36篇
灾害及防治   22篇
  2025年   4篇
  2024年   15篇
  2023年   34篇
  2022年   53篇
  2021年   47篇
  2020年   37篇
  2019年   39篇
  2018年   38篇
  2017年   43篇
  2016年   49篇
  2015年   53篇
  2014年   44篇
  2013年   63篇
  2012年   69篇
  2011年   64篇
  2010年   46篇
  2009年   47篇
  2008年   44篇
  2007年   46篇
  2006年   27篇
  2005年   19篇
  2004年   22篇
  2003年   16篇
  2002年   25篇
  2001年   21篇
  2000年   5篇
  1999年   9篇
  1998年   12篇
  1997年   10篇
  1996年   8篇
  1995年   6篇
  1994年   2篇
  1993年   3篇
  1992年   2篇
  1991年   5篇
  1989年   2篇
  1988年   5篇
  1987年   4篇
  1986年   2篇
  1984年   1篇
  1982年   2篇
  1973年   1篇
  1972年   1篇
排序方式: 共有1045条查询结果,搜索用时 15 毫秒
651.
Journal of Material Cycles and Waste Management - This study used excess sludge from a sewage treatment plant as raw material to extract humic acid (HA) and explore the ability of HA to adsorb Pb2+...  相似文献   
652.
Global emissions of ammonia are approximately 75 Tg N/yr (1 Tg =1012g). The major global source is excreta from domestic animals ( 32 Tg N -1yr-1). Waste storage and treatment lagoonsare used to treat the excreta of hogs in North Carolina (NC). Proteins and nitrogen rich compounds in the lagoon are convertedto ammonia, through a series of biological and chemical transformations. The process of ammonia emission has been investigated using two different model approaches: (1) CoupledMass Transfer with Chemical Reaction Model (Model I), and (2)Mass Transport without Chemical Reaction Model (Model II). Asensitivity analysis is performed with the models, and the modelresults are compared with ammonia emission experiments at a swinewaste storage and treatment lagoon in NC using a dynamic emissionflux chamber.Results of model predictions of emission flux indicate an exponential increase in ammonia flux with increasing lagoontemperature and pH, a linear increase with increasing lagoontotal ammoniacal nitrogen (TAN), and a secondary degree increasewith the increasing wind speed. In addition, the fluxes predictedby Model I are consistently larger than fluxes predicted by Model II. Experimental values of flux agreed well with model predictions, with the experimental values lying in different positions between the two model predictions under different physical and chemical conditions. Further, when compared to diurnal and seasonal experimental flux values, Model I corroborates the results in calm meteorological conditions (windspeed U10 = 1.5 m s-1). However, the observed results are better predicted by Model II during unstable conditions, when wind speeds are higher than 2.0 m s-1 and physical transfer process functions dominate.  相似文献   
653.
新能源汽车电驱动系统实现了量产,进行了产品深度集成技术研究、物料技术研究、总成验证技术研究、产品量产阶段的质量控制研究以及电装工艺评价技术研究等并实现了低成本与高可靠的总体要求,用户反馈良好。  相似文献   
654.
A novel humic acid-based polycarboxylic-type (HAP) dispersant for coal–water slurry (CWS) was successfully synthesized in aqueous solution from the copolymerization of HA, acrylic acid and maleic acid. The structure of HAP was characterized by Fourier transform infrared (FTIR), thermogravimetry (TG) and 1H NMR. With HAP as a dispersant for Linfen coal slurry, the effects of the mass ratio of HA and monomer, initiator concentration, reaction temperature and reaction time on the HAP dispersant performance were discussed by examining the apparent viscosity of CWS. The results showed that CWS prepared withHAP dispersant performed excellent dispersity and stability. When the dosage of HAP was up to 0.5 wt.%, the apparent viscosity of CWS was 505 mPa·s. Experiments on the stability of CWS containing 0.5 wt.% HAP demonstrated that the penetration ratio reached 85.45 % after 96 h, which was higher by 12.87 % than that of CWS prepared with HA. And the CWS produced with HAP had lower dewatering rate within the storage time, which was less 1.85 % than that of CWS with HA when the storage time was 72 h. Furthermore, the maximum coal content of CWS with 0.5 wt.% HAP may reached 70 wt.%. This work found a new route for utilizing humic acid and enlarged the selecting range of the dispersant for CWS. It has a positive significance for protection of environment.  相似文献   
655.
Each year, large quantities of pharmaceuticals and personal care products (PPCPs) are used worldwide. Once conveyed to wastewater treatment plants, PPCPs can remain unchanged or undergo partial or complete transformation during wastewater treatment processes before discharge into the environment via effluent and biosolids for land application. Biosolids can be a major sink for some PPCPs. Previous investigations have indicated that land application of biosolids may be a potential important route through which PPCPs enter the environment. However, no information is available on exactly how closely the concentrations of PPCPs in the environmental media are related to the land application of PPCP-containing biosolids. This paper reviews currently available information on the occurrence of PPCPs in biosolids, methods of analysis, the potential fate of PPCPs in biosolids-applied soils, and composting as a potential means for removal of PPCPs from biosolids.  相似文献   
656.
657.
矿业环境相邻关系的界定是相应环境产权私人化的途径。由矿业环境相邻权与矿业成员环境权双向对接组成的环境相邻关系,通过法律来约束矿山企业的环境相邻权和激励相邻对方的成员环境权而共同保护矿业环境。矿山企业一方给相邻对方合理施加容忍义务,相邻对方应当容忍非实质性的或当地通行的影响。成员环境权的保护,是基于物权而行使消除危险、排除妨害和恢复原状的请求权,基于债权而行使侵害赔偿请求权。  相似文献   
658.
双极膜电渗析法回收丙烯酸丁酯废水中的有机酸   总被引:4,自引:0,他引:4  
采用三隔室型双极膜电渗析装置将丙烯酸丁酯废水中的丙烯酸钠和对甲基苯磺酸钠转化为丙烯酸和对甲基苯磺酸并回收有机酸溶液,研究了料室与酸室初始溶液体积比对转化过程的影响.实验结果表明:当料室与酸室初始溶液体积比为5时,回收的有机酸溶液中丙烯酸和对甲基苯磺酸的质量浓度分别达161.5 g/L和25.0 g/L;整个电渗析过程的...  相似文献   
659.
火电厂脱NOx用SCR催化剂种类及工程应用   总被引:2,自引:3,他引:2  
介绍了SCR法脱除氮氧化物的催化剂种类,着重介绍了商业用钛基脱硝催化剂和现阶段国内脱硝催化剂的应用情况,讨论了导致催化剂中毒的各种原因,阐述了燃煤电厂应用SCR技术中对催化剂的要求。  相似文献   
660.
The aim of this work is to estimate biogas production by anaerobic digestion of agricultural byproduct silage at the low carbon green village in South Korea. The composition of agricultural byproduct from hot pepper farms was analyzed and it was found to be favorable with anaerobic digestion. In the cases of silage materials, the theoretical methane potentials of all of the ensiled materials were increased with silage storage having an increased range from 103 to 120 % compared to that without ensiling. The biochemical methane potential (BMP) tests showed that the ultimate methane potential of ensiled material was measured to be higher than that of raw material without silage storage, while the first order hydrolysis constant was lower. All of the silage materials containing microbial additives used in this study showed higher ultimate methane potentials and first order hydrolysis constants than raw material and silage material without additives. The change of ultimate methane potential was analyzed over time, and all of the test materials, except Day 2, showed higher ultimate methane potential than raw material, Day 0, and the highest was found on Day 40.  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