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   394篇
  免费   22篇
  国内免费   138篇
安全科学   23篇
废物处理   27篇
环保管理   37篇
综合类   206篇
基础理论   70篇
污染及防治   129篇
评价与监测   18篇
社会与环境   21篇
灾害及防治   23篇
  2024年   1篇
  2023年   8篇
  2022年   20篇
  2021年   20篇
  2020年   17篇
  2019年   20篇
  2018年   21篇
  2017年   14篇
  2016年   17篇
  2015年   20篇
  2014年   33篇
  2013年   41篇
  2012年   19篇
  2011年   40篇
  2010年   16篇
  2009年   26篇
  2008年   23篇
  2007年   24篇
  2006年   25篇
  2005年   25篇
  2004年   9篇
  2003年   14篇
  2002年   12篇
  2001年   10篇
  2000年   12篇
  1999年   12篇
  1998年   16篇
  1997年   10篇
  1996年   8篇
  1995年   5篇
  1994年   4篇
  1993年   3篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
排序方式: 共有554条查询结果,搜索用时 62 毫秒
521.
采用混凝沉淀法处理污泥水中的悬浮固体和磷,考察了聚合氯化铝(PAC)、聚硫氯化铝(PACS)以及PAC和阴离子聚丙烯酰胺(aPAM)复配不同投加量对污泥水沉降性能和磷去除的影响。实验结果表明,PAC和PACS混凝处理污泥水效果基本一致,会恶化污泥水沉降,且随PAC投药量的增加,污泥水SV30越大。PAC与aPAM复配混凝处理污泥水,也难以改善污泥水的沉降性能。结果表明,铝盐混凝剂不适合同步去除污泥水悬浮固体和磷,建议先寻求其它混凝剂改善污泥水沉降再用铝盐除磷。  相似文献   
522.
Methotrexate(MTX)is a cytotoxic drug widely used in the treatment of tumors,autoimmune diseases and severe asthma. jen00883 This drug has been frequently detected in the aquatic environment with concentrations up to μg/L levels. The MTX present in environmental water might be transformed and removed during chlorination disinfection treatment. In this work,the fate of MTX during aqueous chlorination was investigated in laboratory batch experiments,and the transformation products of MTX were identified. Aqueous solutions of MTX(1 mg/L)were chlorinated by sodium hypochlorite solution at room temperature under neutral p H conditions. Chlorinated products were pre-concentrated with solid-phase extraction(SPE)cartridges and determined by liquid chromatography electrospray ionization tandem mass spectrometry(LC–ESI–MS/MS). The reaction of MTX chlorination exhibited pseudo-first-order kinetics and the half-life time of MTX degradation was calculated to be 1.65 min,when the initial chlorine concentration was 2 mg/L. Two chlorinated MTX congeners,4-amino-3-chlorinated-N10-methylpteroylglutamic(monochloro-MTX)and 4-amino-3,5-dichloro-N10-methylpteroylglutamic(dichloro-MTX)were found in the chlorinated solution. Monochloro-MTX was successfully fractionated by high performance liquid chromatography(HPLC)and its structure was further identified using ~1H nuclear magnetic resonance(NMR)analysis. The presence of the two products in real hospital wastewater was then examined and both compounds were detected. Finally,the effects of MTX and monochloro-MTX on the cell cycle progression in vitro were evaluated using zebrafish liver cell line. It was found that both compounds could inhibit the proliferation of zebrafish liver cells through S phase arrest and their effects on the cell cycle profile had no significant difference.  相似文献   
523.
回顾近年来再生资源回收利用发布的数据,对国家和行业制定法律、法规、政策、规划和计划起了一定的参谋作用,但缺乏权威性、规范化和准确度,数据相互矛盾的现象时常发生。提供准确数据,既为制定法律、法规、规划和计划提供科学依据,又是相关行业为政府机关和企业服务的重要内容。建立再生资源回收利用数据库迫在眉睫。并提出研究和建立再生资源回收利用数据库的建议。  相似文献   
524.
介绍了油气井中硫化氢的来源、危害,并重点阐述了采油厂含硫化氢油井的分布情况和有关硫化氢的监测和安全防护措施。  相似文献   
525.
Pentachlorophenol could be photocatalytically reduced with superoxide radicals in aqueous solution under simulated sunlight irradiation.  相似文献   
526.
植被固碳能力对气象条件十分敏感,研究植被固碳量变化的气象贡献率,对提升生态环境质量、实现"碳中和"目标具有重要意义.文章基于植被净初级生产力数据和地面气象观测数据,利用相关性分析和模型模拟方法,分析广东省植被固碳量的时空分布特征及其对气象条件的响应规律,并定量研究植被固碳量变化的气象贡献率.结果表明,从空间分布而言,广...  相似文献   
527.
Environmental Science and Pollution Research - Studying the effects of precipitation on carbon exchange in grassland ecosystems is critical for revealing the mechanisms of the carbon cycle. In this...  相似文献   
528.
Environmental Science and Pollution Research - Sandy cropland ecosystems are major terrestrial ecosystems in semi-arid regions of northern China’s Horqin Sandy Land, where they play an...  相似文献   
529.
In order to investigate the effect of different slope-protecting vegetation on soil restoration in the highways, we collected soils at depths of 0-10 cm, 10-20 cm, and 20-30 cm from areas planted with Amorpha fruticosa, Periploca sepium, and Paederia scandens for 6-7 years in the Daming road section of the Daguang Highway, in October 2016. The physico-chemical properties and microbial community of the soils were then analyzed. The soil microbial community was analyzed by terminal restriction fragment length polymorphism (T-RFLP). The correlation between the microbial community and the physico-chemical properties of the soils was determined by redundancy analysis (RDA). The results showed that (1) the physico-chemical properties were the best for soils with Paederia scandens; the nutrient content, water holding capacity, and porosity of the soils with the three types of slope-protecting vegetation were better in the 0-10 cm layer than in the other layers; (2) the contents of soil aggregates (diameter > 5 mm) were the highest in the 0-10 cm and 10-20 cm layers for the soil with Paederia scandens; (3) the dominant bacteria in the 0-10 cm layer and dominant fungi in the 0-10 cm, 10-20 cm, and 20-30 cm layers were higher in the soils with Pe. sepium and Pa. scandens than in the soil with A. fruticosa; and (4) results of RDA showed that the physical properties of the soils were the main factors that influenced the soil microbial community. The physical properties of the soils were sensitive to the change of soil quality. Soil quality can be improved by appropriate management measures, such as burying litter, which can subsequently improve the ecological environment of soils in sloping regions. © 2018 Science Press. All rights reserved.  相似文献   
530.
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