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   1000篇
  免费   205篇
  国内免费   535篇
安全科学   85篇
废物处理   147篇
环保管理   73篇
综合类   984篇
基础理论   212篇
污染及防治   199篇
评价与监测   34篇
社会与环境   5篇
灾害及防治   1篇
  2024年   6篇
  2023年   17篇
  2022年   26篇
  2021年   49篇
  2020年   31篇
  2019年   61篇
  2018年   57篇
  2017年   36篇
  2016年   62篇
  2015年   74篇
  2014年   78篇
  2013年   123篇
  2012年   125篇
  2011年   122篇
  2010年   83篇
  2009年   69篇
  2008年   55篇
  2007年   94篇
  2006年   83篇
  2005年   78篇
  2004年   70篇
  2003年   57篇
  2002年   51篇
  2001年   41篇
  2000年   45篇
  1999年   22篇
  1998年   27篇
  1997年   23篇
  1996年   14篇
  1995年   16篇
  1994年   10篇
  1993年   6篇
  1992年   5篇
  1991年   2篇
  1990年   4篇
  1989年   3篇
  1988年   3篇
  1986年   3篇
  1984年   2篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1973年   2篇
排序方式: 共有1740条查询结果,搜索用时 265 毫秒
81.
树脂吸附法处理对硝基苯乙酮生产废水   总被引:12,自引:0,他引:12  
采用AM-1吸附树脂和ND-900络合树脂对硝基苯乙酮生产废水进行吸附处理,试验结果表明,使用2种树脂串联的处理效果优于单独使用某一种树脂,而且ND-900络合树脂在前,AM-1吸附树脂在后串联处理的效果最好,废水体积为30BV时,COD去除率为92.8%;脱色率为100%,出水由原废水的橙红色变为无色,采用质量分数为8%的NaOH溶液作为脱附剂,脱附效果良好。  相似文献   
82.
The holomictic Traunsee is the deepest and second largest lakein Austria. The special characteristic of this ecosystem isthe fact that local salt and soda industries presumably alterthe lake by the discharge of waste materials. Since thebeginning of the 20th century salt and soda works areannually releasing up to 50,000 tons of solid wastes and up to150,000 tons of chloride into Traunsee. To assess potentialeffects of these anthropogenic impacts on the bacterioplanktonthree sampling sites, influenced as well as not influenced bythe industrial discharge, were chosen for comparison andsampled monthly from November 1997 to October 1998. Bacterialabundance ranged between 0.4 to 3.0 × 106 cells ml-1 with decreasing numbers along the depth profile. Theproportion of actively respiring bacteria, i.e. INT [2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride]reducing cells, never exceeded 10% of DAPI (4',6'-diamidino-2-phenylindole) stained cells. Fluorescence in situ hybridization (FISH) was used to examine the seasonal and spatial distribution of dominant phylogenetic groups of thebacterioplankton. Up to 84% of bacteria detected with DAPIcould be detected via FISH applying the universal bacterialprobe EUB338. Percentages of alpha- and beta-Proteobacteriaand members of the Cytophaga-Flavobacterium cluster did notexceed 60% of DAPI-stained cells.Beta-Proteobacteriaappeared to be the most abundant group, not only in Traunsee butalso in two reference lakes, Attersee and Hallstättersee. No significant differences in any of the bacterial parameters couldbe detected between the three sampling sites and all measurementswere found in the range reported for oligotrophic lakes. The highdischarge of the Traun River, resulting in a lake water renewaltime of only one year, may diminish possible effects of industrial waste discharge in the pelagic zone.  相似文献   
83.
Traunsee is a deep oligotrophic lake in Austria characterised by an artificial enrichment of chloride in the hypolimnion (up to 170 mg L-1) caused by waste disposal of soda and salt industries. Protists were collected monthly over one year, observed alive and after Quantitative Protargol Staining (ciliates) or via epifluorescence microscopy (heterotrophic flagellates). Three sites within the lake (0–40 m depths) were compared to deeper water layers from 60–160 m depths where chloride concentrations and conductivity were increased. In addition, we observed the protozooplankton of two neighbouring lakes, i.e. reference systems, during one sampling occasion. In Traunsee the abundance of ciliates was low (200–36 600 cells L-1) in contrast to high species diversity (at least 60 different species; HS = 2.6) throughout the year. The main pelagic species in terms of abundance were small oligotrichs and prostomatids like Rimostrombidium brachykinetum/hyalinum, Balanion planctonicum and Urotricha spp. throughout the investigation period. Among free-living heterotrophic flagellates, which occurred at densities of 40–2800 cells mL-1, small morphotypes dominated in the pelagial. No differences at the community level between the three lakes could be observed and pelagic ciliates and flagellates seemed not to be affected by increased chloride concentrations or by enhanced conductivity.  相似文献   
84.
石灰-聚铁法处理硫酸厂废水的研究   总被引:5,自引:0,他引:5  
管玉江  陈毓琛 《化工环保》1999,19(6):328-334
对各种处理硫酸厂废水的方法者了探讨,选择了以百石灰和聚合硫酸铁为药剂去除废水中砷,硫等污染物的方法。该法工艺简单,混凝剂投加量少,运行费用低,处理后的废水可达到排放标准。  相似文献   
85.
用蒽醌生产中的废硫酸制备硫酸钾   总被引:2,自引:0,他引:2  
王娉  程秀莲 《化工环保》1999,19(5):298-302
研究了以蒽醌生产中的废硫酸为原料,通过缔合,置换,解缔等步骤,制备硫酸钾的最佳工艺条件。在最佳条件下,可使废硫酸中H2SO4的质量分数从23%降至0.60%,废硫酸成盐率为89.01%,硫酸钾纯度为95.85%。  相似文献   
86.
Traunsee, a 191 m deep Alpine lake in Austria, is affected by industrial tailings from the soda and salt mining industries since 1883. In 1998 littoral water chloride concentrations ranged between 40 and 85 mg L-1 and the highest conductivity was 560 S cm-1, which is almost double as high as the values reported from the two nearby reference lakes. Chloride concentrations increased towards the location of the industrial salt and soda emission into the lake. Analogously to the chloride gradient, the epilithic littoral diatom flora changes towards the waste inlet. Shifts in the species percentages towards the emission source, a high percentage of taxa with large conductivity tolerances, the presence of a small Achnanthes minutissima Kützing morphotype, and occurrences of taxa focused at habitats of higher electrolyte content, indicate subtle impacts on the epilithic diatom flora. An analysis of the seasonal succession of the epilithic diatoms at the waste inlet compared to a lake intern reference site, reveals that only during the late summer period in 1998 the diatom assemblage at the waste inlet became significantly different, indicating seasonally restricted effects of the industrial emissions.  相似文献   
87.
在N2保护下,以硝硬驱铈铵为引发剂,将壳聚糖(CTS)、丙烯酰胺(AM)及二甲基二烯丙基氯化铵(DMDAAC)接枝共聚得到CTS-AM-DMDAAC三元接枝共聚物,考察了反应条件对接枝共聚反应的影响。实验结果表明,在反应温度50℃、反应时间5-6h,m(CTS):m(AM):m(DMAAAC)=1:6:0.67、c(Ce^4+)=0.8mmol/L的最佳反应条件下,接枝共聚反应的接枝率和接枝效率分别为64%和10.5%。用傅里叶变换红外光谱仪对CTS-AM-DMDAAC进行了表征。絮凝实验结果表明:CTS-AM-DMDAAC对高岭土水样具有较强的絮凝能力,可在很宽的pH范围内使用。用CTS-AM-DMDAAC处理COD为165.5mg/L的啤酒生产废水,COD去除率达90.1%.  相似文献   
88.
以桑色素作显色剂,采用流动注射分光光度法测定水中铝的含量。在桑色素质量浓度为0.8g/L、聚氧乙烯辛基苯基醚体积分数为1.0%、进样环体积为400μL、检测波长420nm的条件下,采用流动注射分光光度法对水中铝的含量进行测定,本方法的线性范围为2~300μg/L,检出限(信噪比为3)为0.124μg/L,相对标准偏差为2.9%,加标回收率为96.4%~101.8%。  相似文献   
89.
一氯二乙基铝装置为甲类火灾危险装置。通过对一氯二乙基铝装置工艺流程及各单元工艺特点的详细分析,危险源的辨识从物料危险性、工艺过程危险性、工艺操作危险性等角度展开,从而确定出该装置的重大风险因素。在对一氯二乙基铝装置危险源辨识和分析的基础上,对各工艺单元提出相应的控制措施,预防事故发生。  相似文献   
90.
研究了用聚合氯化铝(PAC)、聚合硫酸铁(PFS)、聚丙烯酰胺(PAM)及改性蒙托石等不同无机—有机高分子絮凝剂复配使用处理炼钢厂连铸含油废水的除油效果,考察了不同絮凝剂的复配以及絮凝剂的不同复配比例对处理效果的影响。试验结果表明,用聚合氯化铝(PAC)+聚合硫酸铁(PFS)+聚丙烯酰胺(PAM)3种絮凝剂复配使用除油效果最佳,当3种絮凝剂的复配比为2∶2∶3时除油效果最好,除油率达到88.2%,达到国家排放标准。  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