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   2585篇
  免费   132篇
  国内免费   792篇
安全科学   163篇
废物处理   131篇
环保管理   249篇
综合类   1401篇
基础理论   375篇
污染及防治   810篇
评价与监测   141篇
社会与环境   142篇
灾害及防治   97篇
  2024年   4篇
  2023年   41篇
  2022年   127篇
  2021年   116篇
  2020年   92篇
  2019年   104篇
  2018年   122篇
  2017年   136篇
  2016年   149篇
  2015年   156篇
  2014年   193篇
  2013年   260篇
  2012年   212篇
  2011年   233篇
  2010年   173篇
  2009年   154篇
  2008年   155篇
  2007年   161篇
  2006年   122篇
  2005年   101篇
  2004年   70篇
  2003年   86篇
  2002年   75篇
  2001年   72篇
  2000年   67篇
  1999年   52篇
  1998年   48篇
  1997年   49篇
  1996年   38篇
  1995年   24篇
  1994年   19篇
  1993年   15篇
  1992年   23篇
  1991年   21篇
  1990年   17篇
  1989年   5篇
  1988年   3篇
  1987年   4篇
  1986年   3篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
排序方式: 共有3509条查询结果,搜索用时 390 毫秒
71.
结合对“社会弱势群体”含义、产生原因的分析以及对我国社会弱势群职业卫生与安全法律保护现状的总结,本文指出了法律对社会弱势群体职业卫生与安全给予倾斜性保护的重要意义,并进一步提出了加强对社会弱势群体职业卫生与安全法律保护具体措施的设想。  相似文献   
72.
在一体式一膜生物反应器处理生活污水的基础上,考察了运行过程中膜污染情况。试验结果表明,膜外表面沉积污泥是造成膜污染的主要因素,在活性污泥混合液中搓洗膜丝,是一种方便而有效的清洗方式。间歇式运行方式的停抽期间最低剩余抽吸压力可用来表征运行过程中膜过滤性能的变化。  相似文献   
73.
To characterize Streptomyces isolated from cattle feces for converting lignocellulose into reducing sugars, five Streptomyces strains were screened. All the strains could convert lignocellulose into reducing sugars. The strain A16 accumulate 3.3-folds more reducing sugars on cottonseed shells treated with ethanol than without the treatment (P?<?0.05). The five strains did not accumulate more reducing sugars on rice straws and wheat brans than those on cottonseed shells. Compared with A10 alone, the microbial combination of F1 + A10 accumulated 19, 61, and 25 % less reducing sugars on cottonseed shell, rice straw, and wheat bran than those by A10 solely, respectively (P?<?0.05). Further studies indicated that the activities of avicelase and xylanase were not correlated with the reducing sugar amount accumulated by the test strains. Strain A7 could produce more cellular lipids with xylose and glucose as the sole carbon sources. This study shows the potential for Streptomyces strains from herbivore feces to convert lignocelluloses into lipids and reducing sugars for fuel production.  相似文献   
74.
随着我国煤气化技术的快速发展,气化渣的产生和排放量逐年增加.煤气化细渣的大量堆存,给当地的环境保护造成了巨大的压力,已经成为限制煤化工产业基地可持续发展急需解决的重大问题.本文针对气化细渣中残碳反应活性低和转化难度大的问题,研究了机械活化法对气化渣残碳反应动力学的影响.采用Coats-Redfern法分析了机械活化对残碳反应活化能的作用规律.结果表明,机械活化8 h,残碳燃烧反应活性显著提高,650℃下的活化能由63.2 k J·mol-1降到28.4 k J·mol-1.不添加其他化学试剂,1000℃烧制高强度轻质陶粒,其堆积密度为0.867 g·cm-3,筒压强度为7.67 MPa.相关研究可以为我国气化细渣的资源化利用提供一定的数据和技术基础.  相似文献   
75.
Journal of Material Cycles and Waste Management - Electroplating sludge contained multi-metals and organics. In previous reports, electroplating sludges were usually recycled by direct calcination...  相似文献   
76.
Environmental Science and Pollution Research - China’s extraordinary economic development has provided the country’s growing population with easier access to animal food products,...  相似文献   
77.
Environmental Science and Pollution Research - In the process of water treatment, excessive nitrogen and phosphorus pollutants are of great concern. Therefore, we prepared nanoscale zerovalent iron...  相似文献   
78.
Environmental Science and Pollution Research - The livestock manure nitrogen load on farmland (LMNLF) is often used to assess the potential environmental pollution risk of livestock manure nitrogen...  相似文献   
79.

Size, morphology, and composition of airborne particles strongly affect human health and visibility, precipitation, and the kinetic characteristics of particles. In this study, the morphology and chemical composition of particles emitted from conventional (diesel and gasoline) and alternative (CNG and methanol) fuel vehicles were characterized through scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The SEM images revealed that the size of primary particles (without agglomeration) was approximately 10 nm in the exhaust from all the tested vehicles. The particles emitted from gasoline vehicle (GV), CNG vehicle (CNGV), and methanol vehicle (MV) had the same median diameter, 62 nm, which was smaller than those from heavy diesel vehicle (HDV) and light diesel vehicle (LDV). Soot was observed in the HDV, LDV, and GV samples but not in the CNGV and MV. The fractal dimension, which was used to quantify the degree of irregularity of soot, was 1.752 ± 0.014, 1.789 ± 0.076, and 1.769 ± 0.006 in the exhaust from HDV, LDV, and GV samples, respectively. The particles discharged by all tested vehicles contained the elements C, O, Fe, and Na. The main element in the samples of HDV, LDV, and GV was C, while O was the main element in the samples of alternative fuel vehicles. The profiles of minor elements were more complex in the emissions of alternative fuel vehicles than those in the emissions of conventional fuel vehicles. The results improved our understanding of the morphology and elemental composition of particles emitted from vehicles powered by diesel, gasoline, CNG, and methanol.

  相似文献   
80.
Environmental Science and Pollution Research - With the development of industry, sustainable use of natural resources has become a worldwide hot topic. Heavy metal–containing sludge (HMS) is...  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