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   1597篇
  免费   166篇
  国内免费   255篇
安全科学   693篇
废物处理   53篇
环保管理   100篇
综合类   788篇
基础理论   120篇
污染及防治   87篇
评价与监测   61篇
社会与环境   46篇
灾害及防治   70篇
  2024年   16篇
  2023年   68篇
  2022年   60篇
  2021年   92篇
  2020年   76篇
  2019年   73篇
  2018年   44篇
  2017年   54篇
  2016年   72篇
  2015年   68篇
  2014年   184篇
  2013年   110篇
  2012年   121篇
  2011年   137篇
  2010年   86篇
  2009年   106篇
  2008年   80篇
  2007年   95篇
  2006年   83篇
  2005年   71篇
  2004年   49篇
  2003年   58篇
  2002年   39篇
  2001年   28篇
  2000年   18篇
  1999年   23篇
  1998年   19篇
  1997年   17篇
  1996年   16篇
  1995年   15篇
  1994年   14篇
  1993年   10篇
  1991年   6篇
  1990年   5篇
  1989年   3篇
  1987年   2篇
排序方式: 共有2018条查询结果,搜索用时 15 毫秒
101.
低溶解氧和磷缺乏引发的非丝状菌污泥膨胀及控制   总被引:9,自引:2,他引:7  
针对污泥培养过程中出现的非丝状菌污泥膨胀,分析了发生膨胀后污泥的特征、性状及其降解污染物性能.反应器中低溶解氧浓度(0~0.7mg/L)和低P/BOD5值(0.78/100) 2种因素共同作用导致污泥膨胀.污泥胞外多聚糖含量越高,污泥憎水性越小,SVI也越高.通过提高溶解氧浓度和P/BOD5值,可使污泥沉降性能得到恢复.此外,向膨胀污泥中投加多孔填料,在不降低处理效能的情况下,很快使系统免受污泥沉降性能恶化的困扰,而向膨胀污泥中投加强氧化剂NaClO并不能有效控制污泥膨胀.  相似文献   
102.
A stain-based screening method was developed to screen different catalyst coatings for their germicidal activity. A Baclight dead/live bacteria viability kit (invitrogen, molecular probes) was used for staining the cell. The screening was carried out following a standard procedure. This included loading cell suspension to solid surface and maintaining contact for 30 min, then staining with a mixture containing dyes. The stained cells were observed using an epifluorescent microscope and photographed with a CCD camera under UV. Metal-doped TiO2 coatings on AI plates were prepared and tested for non-UV germicidal activity without using UV. It was tested using model microorganisms such as Bakers Yeast (Saccharomyces cerevisiae), Bacillus subtilis, Pseudomonas putida, and Escherichia coli. On the basis of the germicidal activity of catalyst and the degree of damage caused to the cells, the stained cells may appear green (viable), green with red or yellow nuclei and yellow (compromised) or red (nonviable). According to their stained color, cells were counted to calculate the percentage of dead, live, and compromised cells. Compromised cells are cells that grow very slowly after reculturing indicating a degree of reversible cell damage. Screening the germicidal activity using this staining method is accurate and efficient, and requires less time than the culture-based method. A modification to the procedure for measuring germicidal activity of rough surfaces or fibrous coatings was developed. Both TiO2 and metal-doped TiO2 (Ag, Pt, Au, Cu) possess non-UV based germicidal activity. The germicidal activity of TiO2 was found to be related with its wetting property and can be improved by UV irradiation before testing. It is not greatly affected by contact time, indicating a fast acting germicidal activity.  相似文献   
103.
春季黄渤海大气气溶胶的离子特征与来源分析   总被引:2,自引:0,他引:2  
薛磊  张洪海  杨桂朋 《环境科学学报》2011,31(11):2329-2335
于2010年春季在黄海、渤海海域采集大气气溶胶总悬浮颗粒物(TSP)样品,并运用离子色谱法对其中主要的水溶性阴离子(Cl-、NO3-、SO24-、CH3SO3-(MSA))和阳离子(Na+、K+、NH4+、Mg2+、Ca2+)浓度进行了测定.分析结果显示,黄海、渤海气溶胶样品中主要水溶性离子总浓度分别为10.2~47....  相似文献   
104.
The effects of arbuscular mycorrhizal fungi (AMF) Glomus mosseae on the responses to elevated O3 in growth and nutrition of snap bean (Phaseolus vulgaris L. cv Guangzhouyuan) were investigated. Exposure was conducted in growth chambers by using three O3 concentrations (20 (CF), 80 (CFO1) and 120 nL/L (CFO2); 8 hr/day for 75 days). Results showed that elevated O3 slightly impacted overall mycorrhizal colonization, but significantly decreased the proportional frequency of hypha and increased the proportional frequency of spores and vesicles, suggesting that O3 had significant effects on mycorrhizal structure. Elevated O3 significantly decreased yield, dry mass and nutrient contents (N, P, K, Ca and Mg) in both non-mycorrhizal and mycorrhizal plants. However, significant interactive effects were found in most variables due to that the reduction by O3 in the mycorrhizal plants was less than that in the non-mycorrhizal plants. Additionally, AMF increased the concentrations of N, P, Ca, and Mg in shoot and root. It can be concluded that AMF alleviated detrimental effects of increasing O3 on host plant through improving plant nutrition and growth.  相似文献   
105.
车辆尾气排放控制技术和排放标准在近年来得到了快速发展,但非尾气管(non-exhaust)排放却很少涉及.非尾气管排放主要包括车辆制动磨损、轮胎磨损、路面磨损和车辆扬尘,本研究调查了北京典型道路车流量和车辆运行速度等参数,应用欧盟非尾气管排放因子分析车辆制动磨损、轮胎磨损和路面磨损PM10排放.结果显示:不同类型道路的...  相似文献   
106.
燃煤电厂烟气氮氧化物排放控制技术发展现状   总被引:4,自引:0,他引:4  
在广泛查阅文献的基础上,对近年来国内外已成功应用和正在研究开发的一些主要的燃煤烟气氮氧化物控制技术进行了介绍。结合我国目前脱硝行业整体水平和国家环保政策要求,对我国脱硝行业技术研发方向提出了建议。  相似文献   
107.
Arbuscular mycorrhizal fungi(AMF) are important components of soil microbial communities,and play important role in plant growth. However, the effects of AMF phylogenetic groups(Glomeraceae and non-Glomeraceae) on host plant under various heavy metal levels are not clear. Here we conducted a meta-analysis to compare symbiotic relationship between AMF phylogenetic groups(Glomeraceae and non-Glomeraceae) and host plant functional groups(herbs vs. trees, and non-legumes vs. legumes) at three heavy metal levels. In the meta-analysis, we calculate the effect size(ln(RR)) by taking the natural logarithm of the response ratio of inoculated to non-inoculated shoot biomass from each study. We found that the effect size of Glomeraceae increased, but the effect size of non-Glomeraceae decreased under high level of heavy metal compared to low level. According to the effect size, both Glomeraceae and non-Glomeraceae promoted host plant growth, but had different effects under various heavy metal levels. Glomeraceae provided more benefit to host plants than non-Glomeraceae did under heavy metal condition, while non-Glomeraceae provided more benefit to host plants than Glomeraceae did under no heavy metal. AMF phylogenetic groups also differed in promoting plant functional groups under various heavy metal levels.Interacting with Glomeraceae, herbs and legumes grew better than trees and non-legumes did under high heavy metal level, while trees and legumes grew better than herbs and non-legumes did under medium heavy metal level. Interacting with non-Glomeraceae, herbs and legumes grew better than trees and non-legumes did under no heavy metal. We suggested that the combination of legume with Glomeraceae could be a useful way in the remediation of heavy metal polluted environment.  相似文献   
108.
在A/A/O普通活性污泥工艺中引入非寡毛类微型后生动物考察其生长条件和对剩余污泥的减量效果及对系统处理效果的影响。结果表明,当进水负荷小于0.5 mg(/mg MLSS·d)时,非寡毛类微型后生动物可大量生长;当内回流比升高、外回流比降低时,更有利于虫体的繁殖。经过适时的运行工艺调整可使生化系统虫体密度和稳定性提高,污泥减量效果可达到40%以上。非寡毛类后生动物的活动与摄食作用提高了系统污泥的沉降性能,并对系统出水COD、NH3-N、TN、TP、SS没有影响。。  相似文献   
109.
采用职业卫生学调查和职业暴露风险评估方法,对选定的苯类物质非密闭操作过程较集中的芳烃装置进行职业暴露分析和评估,为石化企业苯类物质的健康风险控制提供依据。  相似文献   
110.
在DEA窗口分析中引入基于非期望产出的非径向、非角度SBM模型对2006-2011年间我国30个区域的生态效率进行动态的测度和分析。结果表明,在此期间从整体上讲我国的生态效率是进步的,但各个地区的差异较大。生态效率最大的地区在此期间生态效率排名保持前列;生态效率较高的地区其效率变化幅度较大,且效率值是改善的;而生态效率较小的地区其效率变化幅度较小,是波动或者下降的。  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