全文获取类型
收费全文 | 834篇 |
免费 | 189篇 |
国内免费 | 447篇 |
专业分类
安全科学 | 57篇 |
废物处理 | 125篇 |
环保管理 | 73篇 |
综合类 | 873篇 |
基础理论 | 144篇 |
污染及防治 | 167篇 |
评价与监测 | 27篇 |
社会与环境 | 4篇 |
出版年
2024年 | 6篇 |
2023年 | 18篇 |
2022年 | 20篇 |
2021年 | 40篇 |
2020年 | 39篇 |
2019年 | 55篇 |
2018年 | 56篇 |
2017年 | 34篇 |
2016年 | 58篇 |
2015年 | 57篇 |
2014年 | 60篇 |
2013年 | 94篇 |
2012年 | 105篇 |
2011年 | 78篇 |
2010年 | 65篇 |
2009年 | 59篇 |
2008年 | 36篇 |
2007年 | 79篇 |
2006年 | 56篇 |
2005年 | 68篇 |
2004年 | 53篇 |
2003年 | 55篇 |
2002年 | 45篇 |
2001年 | 36篇 |
2000年 | 42篇 |
1999年 | 28篇 |
1998年 | 19篇 |
1997年 | 23篇 |
1996年 | 14篇 |
1995年 | 16篇 |
1994年 | 6篇 |
1993年 | 11篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1470条查询结果,搜索用时 31 毫秒
941.
分析了铝电解工业PM2.5的来源,估计电解铝生产产生的PM2.5大约为66万t/a,加上铝电解工业其他工段产生的粉尘,整个铝冶炼行业产生的PM2.5粉尘达到80万~100万t/a以上。进行铝电解工业废气排放PM2.5控制技术的研究,实际上是对布袋除尘器过滤技术的研究,包括除尘器内部流场控制技术、用于电解铝行业袋式除尘器专用滤料技术、滤袋上滤饼及清灰控制和烟气平衡自适应控制技术的研究。阐述了有关研究方法及阶段性研究成果,以及下一步的研究目标。 相似文献
942.
Matthias Koschorreck René Frömmichen Peter Herzsprung Jörg Tittel Katrin Wendt-Potthoff 《Water, Air, & Soil Pollution: Focus》2002,2(3):97-109
The addition of straw in combination with Carbokalk, a by-product from the sugar-industry, was successfully used to stimulate microbial alkalinity generation in an acidic mining lake. To get detailed information about functions of straw, anenclosure experiment was carried out. Straw bundles were placedat the sediment surface of an acidic mining lake (ML 111) and thephysiochemical conditions and the microbiology of the sediment-water contact zone were studied. Straw was degraded by anaerobic microorganisms and dissolved organic carbon (DOC) leached from straw bundles. Pigmented flagellates responded to the DOC supply in the water column anda considerable amount of algal carbon was transported to the sediment. Straw addition led to microbial reduction of iron andsulfate in the sediment. Sulfate reduction was observed at a pHof 5.5. The pH, however, was not high enough to precipitate H2S completely. Thus, some H2S diffused into the watercolumn, where it was reoxidized. Straw did not create orstabilize an anoxic water body above the sediment. Microbial sulfate reduction and pyrite formation only took place in the sediment,whereas iron reduction also took place in the straw. Straw, however, altered the flow conditions above the sediment surfaceand prevented complete mixing of the profundal water. Straw didnot serve as a substratum for a reactive biofilm. We conclude that the most important function of straw for mining lake remediation is to be a long-term nutrient source for microbialalkalinity generation in the sediment. 相似文献
943.
Hysteresis in Reversal of Central European Mountain Lakes from Atmospheric Acidification 总被引:2,自引:0,他引:2
Kopáček Jiří StuchlÍk Evžen Veselý Josef Schaumburg Jochen Anderson Iris C. Fott Jan Hejzlar Josef Vrba Jaroslav 《Water, Air, & Soil Pollution: Focus》2002,2(2):91-114
Extremely high emissions of S and N compounds in Central Europe (both 280 mmol m-2 yr-1) declined by 70and 35%, respectively, during the last decade. Decreaseddeposition rates of SO4
-2, NO3
-, and NH4
+ in the region paralleled emission declines. The reduction in atmospheric inputs of S and N to mountain ecosystemshas resulted in a pronounced reversal of acidification in the Tatra Mountains and Bohemian Forest lakes. Between the 1987–1990and 1997–1999 periods, concentrations of SO4
-2 and NO3
- decreased (average ± standard deviation) by 22±7 and 12±7 mol L-1, respectively, in theTatra Mountains, and by 19±7 and 15±10 mol L-1, respectively, in the Bohemian Forest. Their decrease was compensated in part (1) by a decrease in Ca2+ + Mg2+ (17±7 mol L-1) and H+ (4±6 mol L-1), and an increase in HCO3
-(10±10 mol L-1) in the Tatra Mountains lakes, and (2) by a decrease in Al (7±4 mol L-1), Ca2+ + Mg2+ (9±6 mol L-1), and H+ (6±5 mol L-1), in Bohemian Forest lakes. Despite the rapid decline in lake water concentrations of SO4
-2 and NO3
- in response to reduced S and N emissions, their present concentrations in some lakes are higher than predictionsbased on observed concentrations at comparable emission rates during development of acidification. This hysteresis in chemical reversal from acidification has delayed biological recovery of the lakes. The only unequivocal sign of biological recovery hasbeen observed in erné Lake (Bohemian Forest) where a cladoceran species Ceriodaphnia quadrangular has recentlyreached its pre-acidification abundance. 相似文献
944.
945.
Jody N. Connor Gerald N. Smith 《Journal of the American Water Resources Association》1986,22(4):661-664
ABSTRACT: Alum and sodium aluminate were injected into the hypolimnion of eutrophic Kezar Lake, New Hampshire, with a specially designed applicator mechanism. This new method of applying aluminum salts to achieve phosphorus inactivation included two separate chemical distribution systems mounted on a hydraulic weed harvester. The design of the applicator system is described, and its cost-effectiveness is compared with other aluminum salt injections. 相似文献
946.
通过研究硫酸盐还原菌(SRB)污泥固定化小球还原硫酸盐过程硫酸盐浓度的变化规律,建立了反应动力学方程,确定了pH值和球液配比量对反应速率常数的影响,计算了相应的反应表观活化能.结果表明: SRB还原硫酸盐的反应为一级反应,反应动力学方程为:V=-dC/dt=0.080 56C.pH值为6-7时,SRB还原硫酸盐的反应速率常数相差不大,pH<4和pH>10时,反应速率常数逐渐减小.球液配比量减少,反应速率常数也随之减小,反应表观活化能增大.在实验条件下,SRB还原硫酸盐属化学控制.并由此确定了SRB污泥固定化小球还原硫酸盐的最佳工艺条件为温度35 ℃、pH值6-7、球液配比量1∶10(g/mL). 相似文献
947.
利用CSTR 反应器,考察了COD和硫酸盐浓度致变下的COD/SO42-比值对硫酸盐还原的影响.发现在(34±1) ℃、水力停留时间20 h、进水碱度(ALK)300-500 mg/L、pH 6.0-6.2等条件下:①相同 COD/SO42-值下,硫酸盐致变与COD致变时硫酸盐的去除率并不相同,其中硫酸盐致变时的去除率要高于COD致变时的去除率;②要使产酸脱硫反应器保持较高的SO42-去除率(大于80%)和运行稳定性,须将系统的COD/SO42-值控制在不小于2.0的水平. 相似文献
948.
Coastal environments in Australia are under development pressures. Human settlement encroaches on disease vector salt marsh mosquito breeding areas that are underlain by potential acid sulfate soils (PASS). Altering the hydrology by runneling solves the mosquito problem but may lead to acid sulfate problems. Appropriate analytical tools can assess the risk to the environment. The objective of the research was to compare three methods of assessing PASS. The study area was a low-lying intertidal subtropical salt marsh that was being considered for runneling. The results indicated that using field pH and field peroxide pH (and the relationship between these), and also the peroxide oxidation-combined acidity and sulfate (POCAS) test, appeared to overestimate the potential acidity. This was because the source of acidity in the intertidal salt marsh includes a large organic content, which is not a major environmental concern. The chromium-reducible sulfur test, which is not affected by organic content, was found to provide the most appropriate assessment, and is recommended for use in highly organic salt marshes. 相似文献
949.
950.
以镍钴合金切削废料为原料,通过酸溶、除铁、除铬、镍钴分离等一系列步骤,回收镍和钴,生产硫酸镍和氯化钴,通过试验确定了最佳工艺条件,并对经济效益进行了分析。 相似文献