全文获取类型
收费全文 | 676篇 |
免费 | 93篇 |
国内免费 | 330篇 |
专业分类
安全科学 | 112篇 |
废物处理 | 105篇 |
环保管理 | 74篇 |
综合类 | 558篇 |
基础理论 | 73篇 |
污染及防治 | 152篇 |
评价与监测 | 23篇 |
社会与环境 | 1篇 |
灾害及防治 | 1篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 13篇 |
2021年 | 30篇 |
2020年 | 37篇 |
2019年 | 32篇 |
2018年 | 43篇 |
2017年 | 33篇 |
2016年 | 39篇 |
2015年 | 43篇 |
2014年 | 45篇 |
2013年 | 59篇 |
2012年 | 84篇 |
2011年 | 67篇 |
2010年 | 40篇 |
2009年 | 48篇 |
2008年 | 32篇 |
2007年 | 59篇 |
2006年 | 40篇 |
2005年 | 46篇 |
2004年 | 40篇 |
2003年 | 45篇 |
2002年 | 34篇 |
2001年 | 27篇 |
2000年 | 34篇 |
1999年 | 34篇 |
1998年 | 13篇 |
1997年 | 14篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1994年 | 2篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1099条查询结果,搜索用时 250 毫秒
441.
钢渣处置工艺的清洁生产研究与实施 总被引:1,自引:0,他引:1
该课题研究了用水淬法和蒸汽法相结合的技术消除钢渣中的游离氧化钙;用传统的破碎磁选与高精度的强磁选相结合,以独创的递进除铁技术使钢渣中的含铁量由18%降至1%;用专项技术改制的管式磨、活化环,蒸汽熟化,递进式除铁,o-sepa选粉,高频振动粉磨,PPC集料器组成钢渣微粉清洁生产工艺.结果表明该工艺在国内尚属首例,具有较好的推广应用价值. 相似文献
442.
软锰矿浆烟气脱硫技术 总被引:5,自引:0,他引:5
软锰矿浆烟气脱硫技术不权脱硫率高,而且可以获得硫酸锰等产品。本文对这种脱硫技术的研究工作进行综述,介绍其反应原理,评价已用吸收器的性能,并就有关参数对脱硫率和连二硫酸锰的生成的影响进行讨论。 相似文献
443.
积云中H2O2液相氧化S(Ⅳ)的数值模拟 总被引:3,自引:1,他引:3
用一个液相化学反应和一维时变积云动力学过程相结合的模式,取不同的[SO_2]和[H_2O_2],对积云发展过程中由H_2O_2液相氧化云中S(Ⅳ)而形成的SO_4~(2-)、其它离子以及云水pH值的时空分布进行了数值模拟计算。 计算结果表明,在积云的中、上部呈现硫酸盐的高值中心和pH的低值中心,而在积云的底部,由于NH_3·H_2O的离解,形成高浓度的OH~-和NH_4~+,可使云内液态水的pH值增至大于5.6;大气中SO_2和H_2O_2浓度的改变,对云内液态水的酸化均具有重要的影响;由于化学反应的参与,H_2O_2使S(Ⅳ)转化成S(Ⅵ)是一复杂的非线性问题。 相似文献
444.
445.
446.
Degradation of benomyl, picloram, and dicamba in a conical apparatus by zero-valent iron powder 总被引:6,自引:0,他引:6
Ghauch A 《Chemosphere》2001,43(8):1109-1117
Reduction of some pesticides (benomyl, picloram, and dicamba) was studied in an aerobic batch conical pilot system to investigate the disappearance of these pesticides on contact with iron powder (20 g/l, 325-mesh). Aqueous buffered solutions of the compounds were added to the system followed by zero-valent iron powder (ZVIP), and the decline in the pesticide concentrations was monitored over time. HPLC analyses show a complete disappearance of picloram (1.20 mg/l) after 20 min of reaction. Benomyl (1.00 mg/l) and dicamba (1.25 mg/l) disappear after 25 and 40 min, respectively. The t50 values ranged from 3 to 5.5 min, and were about slightly less than the t1/2 values reported when the log of the relative HPLC peak area was plotted versus time, where the relative peak area was calculated by dividing the measured peak area by the initial peak area. Pathways for the degradation of the studied pesticides by ZVIP are proposed. 相似文献
447.
油田水反硝化技术抑制硫酸盐还原菌活性研究进展 总被引:7,自引:0,他引:7
综述了国内外应用反硝化技术抑制硫酸盐还原的沿革和最新进展。随着油田系统采出水中SRB造成危害的日益严重,常规的物理和化学法因其高成本、低效率等原因已不能满足需求,生态抑制法逐渐受到人们关注。着重介绍了反硝化技术对硫酸盐还原的抑制作用,阐述了当前国内外学者在此领域的研究现状,总结了研究者提出的几种机理,重点介绍了生物竞争抑制机制、中间产物抑制机制、形成厌氧硫循环机制、同时具有反硝化和硫酸盐还原的细菌作用机制以及电位抑制机制。列举了国内外成功应用反硝化抑制硫酸盐还原的成功实例,并总结了该领域研究的热点问题。 相似文献
448.
Sara A. Heller Henry W. Rauch 《Journal of the American Water Resources Association》1986,22(4):581-585
ABSTRACT: Many water wells developed in the Middle Mississippian Greenbrier Group of central Greenbrier County, West Virginia, are very productive because of the abundant solution conduits in this karst aquifer. Water from these wells, all of which (with one exception) are clustered in a small area about eight kilometers northwest of Lewisburg, West Virginia, is typically very hard (calcium-magnesium-bicarbonate type). Of 74 wells sampled, eight showed sulfate concentrations ranging from 600 to 1700 mg/l. These wells also showed a much higher than average concentration of calcium, magnesium, chloride, sodium, and, in a few cases, iron. The water from several of these wells was not potable. Previously unpublished work has suggested that dolomite and gypsum dissolution have contributed magnesium and sulfate ions to the ground water. It is also likely that, where sodium, chloride, and iron concentrations are above background, halite dissolution and pyrite oxidation are contributing to the problem. All of these minerals are often associated with the basal waterbearing strata of the Greenbrier Group. In addition, it is possible that the wells are receiving deeply circulating ground waters, via fracture zones, which feed many other well-known sulfur and/or thermal springs in the central Appalachians. 相似文献
449.
Selective catalytic reduction (SCR) denitration may increase the emission of NH4+ and NH3. The removal and transformation characteristics of ammonium sulfate aerosols and ammonia slip during the wet flue gas desulfurization (WFGD) process, as well as the effect of desulfurization parameters, were investigated in an experimental system equipped with a simulated SCR flue gas generation system and a limestone-based WFGD system. The results indicate that the ammonium sulfate aerosols and ammonia slip in the flue gas from SCR can be partly removed by slurry scrubbing, while the entrainment and evaporation of desulfurization slurry with accumulated NH4+ will generate new ammonium-containing particles and gaseous ammonia. The ammonium-containing particles formed by desulfurization are not only derived from the entrainment of slurry droplets, but also from the re-condensation of gaseous ammonia generated by slurry evaporation. Therefore, even if the concentration of NH4+ in the desulfurization slurry is quite low, a high level of NH4+ was still contained in the fine particles at the outlet of the scrubber. When the accumulated NH4+ in the desulfurization slurry was high enough, the WFGD system promoted the conversion of NH3 to NH4+ and increased the additional emission of primary NH4+ aerosols. With the decline of the liquid/gas ratio and flue gas temperature, the removal efficiency of ammonia sulfate aerosols increased, and the NH4+ emitted from entrainment and evaporation of the desulfurization slurry decreased. In addition, the volatile ammonia concentration after the WFGD system was reduced with the decrease of the NH4+ concentration and pH values of the slurry. 相似文献
450.
基于聚合硫酸铁的UV-vis光谱学特征,利用外加电磁场对聚合硫酸铁进行磁化调控,研究了不同磁化时间和磁场强度对PFS中铁形态分布的影响.研究表明,水解过程中铁盐逐渐与羟基结合,存在由低聚态向相对较高聚态转化的趋势.整体来看,在一定范围内增加磁化时间和磁场强度可以有效促进絮凝剂的水解,但是在多工艺参数调控中,提升磁场强度能够获得更为明显的效果.通过上述研究表明,借助UV-vis光谱学特征变化的分析,可有效判断PFS在水解过程中的水解进程及转化.在相同磁场强度下,磁化4~6min时,由低聚态向高聚态转化速率更快.而在控制磁化时间相同的情况下,增大磁场强度相应水解产物的转化速率也会提高1.9%~12.3%.该研究为设计适当的磁场强度获得更好的磁絮凝效果以及PFS絮凝工艺的调控提供更为科学有效的理论指导. 相似文献