全文获取类型
收费全文 | 418篇 |
免费 | 20篇 |
国内免费 | 109篇 |
专业分类
安全科学 | 71篇 |
废物处理 | 20篇 |
环保管理 | 69篇 |
综合类 | 210篇 |
基础理论 | 65篇 |
污染及防治 | 69篇 |
评价与监测 | 33篇 |
社会与环境 | 9篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 7篇 |
2022年 | 11篇 |
2021年 | 17篇 |
2020年 | 14篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 14篇 |
2015年 | 17篇 |
2014年 | 9篇 |
2013年 | 22篇 |
2012年 | 19篇 |
2011年 | 18篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 19篇 |
2007年 | 41篇 |
2006年 | 28篇 |
2005年 | 31篇 |
2004年 | 23篇 |
2003年 | 31篇 |
2002年 | 29篇 |
2001年 | 18篇 |
2000年 | 27篇 |
1999年 | 18篇 |
1998年 | 19篇 |
1997年 | 15篇 |
1996年 | 6篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有547条查询结果,搜索用时 31 毫秒
291.
染料在干污泥上的吸附平衡和动力学 总被引:16,自引:0,他引:16
本文研究了染料活性嫩黄 KD- 3G、直接深棕 M和酸性媒介棕 RH在干活性污泥上的吸附平衡和吸附动力学。结果表明 :所试染料的吸附等温线数据都可用 Freundlich方程描述 ;对于 Langmuir方程 ,只有酸性媒介深棕 RH的等温线数据能与之拟合。染料的吸附过程遵循二级吸附动力学模型 ,也能用 Lagergren一级速率方程描述。在吸附温度为 1 5℃、2 0℃、2 5℃、35℃和 45℃时 ,活性嫩黄 KD-3G、直接深棕 M和酸性媒介棕 RH的一级吸附速率常数分别为 0 .0 0 2 8~ 0 .0 0 3 2 min- 1、0 .0 1 5~ 0 .0 4 0 min- 1、0 .0 0 7~ 0 .0 1 2 min- 1 ,二级吸附速率常数分别为 0 .0 0 0 2 7~ 0 .0 0 0 4 7g/ (mg· min)、0 .0 0 6 5~ 0 .0 2 90 g/ (mg· min)、0 .0 0 3 0~ 0 .0 1 3 2 g/ (mg· min)。由二级吸附速率方程计算得到的平衡吸附量与实验值的相对误差在 1 0 %以内 ,这表明两者的符合程度较高。上述温度范围内 ,当染料质量浓度为50 mg/ L时 ,活性嫩黄 KD- 3G、直接深棕 M和酸性媒介棕 RH的平衡吸附量分别为 1 6.5~ 1 9.2 mg/ g、1 4 .3~ 1 6.0 mg/ g、7.2~ 9.6 mg/g。试验溶液的温度对吸附速率常数有影响 相似文献
292.
293.
294.
Martin B. Hocking 《Environmental management》1986,10(2):179-187
Here are assembled representative excerpts from a new text in applied chemistry. They illustrate the well-referenced treatment of industrial processes that are here considered with their related emission control problems and solutions. A brief account of general aspects of the industry is followed by surveys of the significance and technical aspects of air and water pollution chemistry. Consideration is given to emission avoidance or containment, waste treatment, and waste disposal options as they relate to both of these environmental areas. Details of salt recovery and the products of brine electrolysis plus environmental aspects of these operations are treated as examples of some of the processes discussed. Also covered are fertilizer constituent preparation, formulation, and use with consideration of the large-scale effects of each of these activities. Detailed reference is made to the chemical technology and emission control aspects of the pulp and paper industry and refinery operations. Throughout, integral process changes and waste recycling practices are directly related to emission control aspects of each process in a way to be useful to the student and professional alike. These excerpts are extracted from one of the first, single volume accounts to take this unified approach to the subject.Extract from the bookModern Chemical Technology and Emission Control by M. B. Hocking, published by Springer-Verlag, Berlin, Heidelberg, New York, Tokyo (1985). 相似文献
295.
Robert L. Edmonds Ted B. Thomas Roger D. Blew 《Journal of the American Water Resources Association》1995,31(3):409-419
ABSTRACT: The biogeochemistry of a coastal old-growth forested watershed in Olympic National Park, Washington, was examined. Objectives were to determine: (1) concentrations of major cations and anions and dissolved organic C (DOC) in precipitation, throughfall, stemflow, soil solution and the stream; (2) nutrient input/output budgets; and (3) nutrient retention mechanisms in the watershed. Stemilow was more acidic (pH 4.0–4.5) than throughfall (pH 5.1) and precipitation (pH 5.3). Organic acids were important contributors to acidity in throughfall and stemflow and tree species influenced pH. Soil solution pH averaged 6.2 at 40 cm depth. Stream pH was higher (7.6). Sodium (54.0 μeq L-1) and Cl (57.6 μeq L?1) were the dominant ions in precipitation, reflecting the close proximity to the ocean. Throughfall and stemflow were generally enriched in cations, especially K. Cation concentrations in soil solutions were generally less than those in stemilow. Ion concentrations increased in the stream. Dominant ions were Ca (759.7 μeq L?1), Na (174.4 μeq L?1), HCO3 (592.0 μeq L?1), and SO4 (331.5 μeq L?1) with seasonal peaks in the fall. Bedrock weathering strongly influenced stream chemistry. Highest average NO3 concentrations were in the stream (5.2 μeq L?1) with seasonal peaks in the fall and lowest concentrations in the growing season. Nitrogen losses were similar to inputs; annual inputs were 4.8 kg/ha (not including fixation) and stream losses were 7.1 kg/ha. Despite the age and successional status of the forest, plant uptake is an important N retention mechanism in this watershed. 相似文献
296.
为了降低COD测定成本,减小试剂污染,介绍了一种测定量程为0~1 500 mg/L的HACHCOD替代试剂.重点讨论了组分配比、标准曲线、消解管磨损等因素对测定结果的影响,并提出一系列提高测定质量,减少测定误差的措施.该替代试剂配比为0.5 mL 1/6 K2Cr2O7 (1.00 mol/L) 2.5 mL 1% H2SO4-Ag2SO4 0.04 g HgSO4,在组成上接近于HACH原装试剂,使用内置程序测定的误差介于2.79%~5%之间,使用对应的程序测定误差为0.23%~2.64%.实验证明,与HACH原装试剂、传统重铬酸钾法相比,该替代试剂在测定准确度方面无明显差异,3种方法的平均变异系数分别为1.87%、2.37%和3.71%,测定精密度满足要求, t 均小于 t 0.95,测定结果准确可靠.经济技术比较显示替代试剂具有操作简单,成本低,污染小,适合批量测定等优势.单个样品的平均测定成本仅为0.78 元. 相似文献
297.
Marcel van der Perk Philip N. Owens Lynda K. Deeks Barry G. Rawlins 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):443-451
A spatially extensive geochemical data set of stream water and bed sediment composition across the Tamar catchment in south-west
England was analysed to identify the key bed sediment properties that control the in-stream dissolved reactive phosphorus
(DRP) concentrations during baseflow conditions. Linear regression analysis of the streamwater DRP concentrations and the
distribution coefficient K
d for DRP revealed that the former is positively correlated with total SiO2 and Al2O3, and negatively correlated with K2O. The primary control on these major element distributions is the dominant bedrock geology. The data suggest that streamwater
DRP concentrations are mainly controlled by adsorption to clay minerals. Where P concentrations in streamwater were considerably
elevated by inputs from point sources, DRP concentrations are also controlled by precipitation of hydroxyapatite. 相似文献
298.
299.
绿色化学是一门从源头上阻止污染的化学,它吸收了传统化学化工、环境、物理、生物、材料和信息等学科的最新理论和技术,代表了化学化工科学理念的重大变革,具有可持续发展的意义。本文介绍了绿色化学的一般概念及绿色化学与环境保护的关系,从主要研究内容及发展现状和趋势等方面阐明了绿色化学是可持续发展的必由之路。 相似文献
300.
有机磷农药对海洋扁藻毒性构效关系的密度泛涵理论研究 总被引:3,自引:2,他引:1
采用密度泛函理论方法,在B3LYP/6-311G**水平上,计算了11个有机磷农药化合物的结构参数,将结构参数作为理论描述符,导出了有机磷类化合物的分子结构参数与2种盐度(S=20,S=30)下扁藻毒性(-lgEC50)的定量关系式(式(3)和(6)),并用交叉验证法验证,相关系数R分别为0.923 2和0.893 3,交叉验证相关系数q2分别为0.527 0和0.540 5.在此基础上,预测了11种有机磷农药的毒性.研究表明,所得预测方程有较好的稳定性和较强的预测能力.可用于有机磷化合物的-lgEC50预测. 相似文献