全文获取类型
收费全文 | 1629篇 |
免费 | 658篇 |
国内免费 | 125篇 |
专业分类
安全科学 | 101篇 |
废物处理 | 176篇 |
环保管理 | 157篇 |
综合类 | 1127篇 |
基础理论 | 324篇 |
环境理论 | 2篇 |
污染及防治 | 354篇 |
评价与监测 | 122篇 |
社会与环境 | 45篇 |
灾害及防治 | 4篇 |
出版年
2025年 | 7篇 |
2024年 | 49篇 |
2023年 | 67篇 |
2022年 | 61篇 |
2021年 | 53篇 |
2020年 | 42篇 |
2019年 | 55篇 |
2018年 | 59篇 |
2017年 | 80篇 |
2016年 | 98篇 |
2015年 | 112篇 |
2014年 | 107篇 |
2013年 | 127篇 |
2012年 | 164篇 |
2011年 | 164篇 |
2010年 | 87篇 |
2009年 | 106篇 |
2008年 | 85篇 |
2007年 | 123篇 |
2006年 | 156篇 |
2005年 | 94篇 |
2004年 | 59篇 |
2003年 | 72篇 |
2002年 | 54篇 |
2001年 | 53篇 |
2000年 | 46篇 |
1999年 | 44篇 |
1998年 | 32篇 |
1997年 | 29篇 |
1996年 | 34篇 |
1995年 | 19篇 |
1994年 | 20篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1979年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有2412条查询结果,搜索用时 0 毫秒
971.
This paper presents the photo-catalytic degradation of real refinery wastewater from National Refinery Limited (NRL) in Karachi, Pakistan, using TiO2, ZnO, and H2O2. The pretreatment of the refinery effluent was carried out on site and pretreated samples were tested at 32–37 °C in a stirrer bath reactor by using ultra-violet photo oxidation process. The degradation of wastewater was measured as a change in initial chemical oxygen demand (COD) and with time. Optimal conditions were obtained for catalyst type, and pH. The titanium dioxide proved to be very effective catalysts in photo-catalytic degradation of real refinery wastewater. The maximum degradation achieved was 40.68% by using TiO2 at 37 °C and pH of 4, within 120 min of irradiations. When TiO2 was combined with H2O2 the degradation decreased to 25.35%. A higher reaction rate was found for titanium dioxide. The results indicate that for real refinery wastewater, TiO2 is comparatively more effective than ZnO and H2O2. The experiments indicated that first-order kinetics can successfully describe the photo-catalytic reaction. The ANOVA results for the model showed satisfactory and reasonable adjustment of the second-order regression model with the experimental data. The ANOVA results also showed that pH is significant than reaction time and catalyst dosage of TiO2; and in case of ZnO, reaction time is significant than pH and catalyst dosage. This study proves that real refinery wastewater reacts differently than synthetic refinery wastewater, oil field produced water or oil water industrial effluent. 相似文献
972.
Joseph A. Senecal 《Journal of Loss Prevention in the Process Industries》1991,4(5):332-337
A process dust explosion in a manganese pulverizing plant is described and probable causes of the incident are discussed. Explosibility and ignition characterization data are presented. An assessment is made of the feasibility of the use of deflagration suppression as a method of explosion protection in fine metal powder process systems. 相似文献
973.
974.
用二氧化硫处理含铬废水 总被引:5,自引:2,他引:5
采用二氧化作还原剂,处理高浓度大流量含铬废水,除铬效果良好,进水中产价铬含量为90.0-430.8mg/L时,经还原,沉淀处理后,出水中六价铬含量均可达到排放标准,该工艺基本上实现了二氧化硫的闭路循环,排放尾气中二氧化硫含量〈15mg/L。 相似文献
975.
根据SO2减排控制指标体系中16个指标的概况和变化趋势,对中国2020年SO2排放量做了系统地分析和预测,得到了三组预测图像。中国SO2排放量与国民生产总值(GDP)及其年均增长率、总能耗量及其年均增长率、能源经济环境发展模式(能源消费弹性系数)等12项指标成正相关,与SO2治理强度等4项指标成负相关,当各个指标控制在合理的范围内时我国2020年SO2减排目标是可以实现的。提出了2020年实现SO2减排目标的10个约束条件,如果不满足约束条件时,我国2020年SO2削减目标是不能实现的。 相似文献
976.
二氧化钛纳米材料的合成及其在环保领域的应用研究进展 总被引:19,自引:0,他引:19
综述了近年来纳米TiO2光催化剂在制备方法、表面改性、光催化氧化机理及应用方面的研究进展,提出了半导体催化剂的研究发展的方向。 相似文献
977.
煤浆洗涤法去除烟气中的SO2 总被引:1,自引:1,他引:1
分别以高硫原煤、低硫原煤和中煤配制的煤浆作为洗涤介质,去除烟气中的SO2。反应温度高于40℃时,采用高硫原煤煤浆洗涤烟气,SO2去除率在90%以上;O2含量对SO2去除率影响不大;SO2去除率随其含量的增加而降低。低硫原煤煤浆同样可用于烟气脱硫,随温度的升高,煤浆pH的降低幅度和SO2去除率均增大,与用高硫原煤时的情况类似。中煤煤浆亦能有效去除烟气中的SO2,反应过程中煤浆pH的降低对SO2去除率的影响不大。在烟气脱硫的同时,3种煤中的黄铁矿均被不断浸出,浸出铁质量浓度随反应时间的延长和SO2去除率的增大而增加。 相似文献
978.
Within the European monitoring network (EMEP, ) several different sampling procedures for measuring the main air components have been applied. This has contributed to systematic
concentration differences and a comparability problem. Since 1997 co-located experiments in 15 countries have been carried
out to quantify these differences. In addition, three major measurement campaigns were organized by EMEP between 1985 and
1991. Differences among results depend on the concentration level and methods used. The decrease in SO2 concentrations over the last twenty years has placed greater demands on the methodology. Absorbing solutions methods for
SO2, (H2O2 and tetrachloromercurate (TCM)) typically have higher detection limits than the reference method, which uses KOH impregnated
filters. The TCM method also has problems with negative interference, especially in summertime. UV fluorescence monitors have
in a few cases proven to give good results, but interferences, detection limit and poor maintenance can be problems. For NO2, many countries are using the TGS absorption solution method, which has a higher detection limit than the reference method
using NaI impregnated glass sinters. The Salzmann method gives unreliable results at concentrations below 1 μgN/m3, and even at higher concentrations the uncertainty is rather unsatisfactory. The chemiluminescence monitor with molybdenum
converters tends to systematically overestimate NO2 concentrations, possibly because zero-drift problems and the non-specific response to NO2. Particulate sulphate measurements in general have lower bias and uncertainties than gas and other aerosol measurements. 相似文献
979.
980.
在离子液体1-丁基-3-甲基咪唑四氟化硼([C4MIM]BF4)的辅助下,采用溶胶-凝胶法制备了Nd掺杂Ti O2光催化剂(Nd-Ti O2(IL))。实验结果表明:在加入[C4MIM]BF4、n(Nd)∶n(Ti O2)=2.5%的条件下制得的Nd-Ti O2(IL)(记作2.5%Nd-Ti O2(IL))的光催化性能最好;在初始亚甲基蓝质量浓度10 mg/L、2.5%Nd-Ti O2(IL)加入量1 g/L的条件下,光催化反应180 min,亚甲基蓝降解率为84%,2.5%Nd-Ti O2(IL)光催化降解亚甲基蓝的表观速率常数为0.010 9 min-1。表征结果显示:Nd的掺杂抑制了Ti O2晶粒长大,增大了Ti O2的比表面积,2.5%Nd-Ti O2(IL)的比表面积为80.77 m2/g;[C4MIM]BF4的加入提高了Ti O2的晶化度;Nd以Nd3+的形式,通过晶格取代方式进入Ti O2晶格。 相似文献