全文获取类型
收费全文 | 480篇 |
免费 | 70篇 |
国内免费 | 238篇 |
专业分类
安全科学 | 45篇 |
废物处理 | 92篇 |
环保管理 | 44篇 |
综合类 | 359篇 |
基础理论 | 99篇 |
污染及防治 | 121篇 |
评价与监测 | 25篇 |
社会与环境 | 2篇 |
灾害及防治 | 1篇 |
出版年
2024年 | 3篇 |
2023年 | 7篇 |
2022年 | 8篇 |
2021年 | 19篇 |
2020年 | 13篇 |
2019年 | 21篇 |
2018年 | 16篇 |
2017年 | 15篇 |
2016年 | 30篇 |
2015年 | 37篇 |
2014年 | 32篇 |
2013年 | 58篇 |
2012年 | 47篇 |
2011年 | 56篇 |
2010年 | 29篇 |
2009年 | 28篇 |
2008年 | 30篇 |
2007年 | 44篇 |
2006年 | 45篇 |
2005年 | 42篇 |
2004年 | 38篇 |
2003年 | 24篇 |
2002年 | 26篇 |
2001年 | 19篇 |
2000年 | 27篇 |
1999年 | 14篇 |
1998年 | 17篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有788条查询结果,搜索用时 15 毫秒
641.
Jitendra Kumar Keyath Nisar N. A. Shakil Suresh Walia Rajender Parsad 《Journal of environmental science and health. Part. B》2013,48(4):330-335
Controlled release (CR) formulations of metribuzin in Polyvinyl chloride [(PVC) (emulsion)], carboxy methyl cellulose (CMC), and carboxy methyl cellulose-kaolinite composite (CMC-KAO), are reported. Kinetics of its release in water and soil was studied in comparison with the commercial formulation (75 DF). Metribuzin from the commercial formulation became non-detectable after 35 days whereas it attained maxima between 35–49 days and became non-detectable after 63 days in the developed products. Amongst the CR formulations, the release in both water and soil was the fastest in CMC and slowest in PVC. The CMC-KAO composite reduced the rate of release as compared to CMC alone. The diffusion exponent (n value) of metribuzin in water and soil ranged from 0.515 to 0.745 and 0.662 to 1.296, respectively in the various formulations. The release was diffusion controlled with half release time (t1/2) from different controlled release matrices of 12.98 to 47.63 days in water and 16.90 to 51.79 days in soil. It was 3.25 and 4.66 days, respectively in the commercial formulation. The period of optimum availability of metribuzin in water and soil from controlled released formulations ranged from 15.09 to 31.68 and 17.99 to 34.72 days as against 5.03 and 8.80 days in the commercial formulation. 相似文献
642.
Methyl chloride emissions from halophyte leaf litter: dependence on temperature and chloride content
Derendorp L Wishkerman A Keppler F McRoberts C Holzinger R Röckmann T 《Chemosphere》2012,87(5):483-489
Methyl chloride (CH3Cl) is the most abundant natural chlorine containing compound in the atmosphere, and responsible for a significant fraction of stratospheric ozone destruction. Understanding the global CH3Cl budget is therefore of great importance. However, the strength of the individual sources and sinks is still uncertain. Leaf litter is a potentially important source of methyl chloride, but factors controlling the emissions are unclear. This study investigated CH3Cl emissions from leaf litter of twelve halophyte species. The emissions were not due to biological activity, and emission rates varied between halophyte species up to two orders of magnitude. For all species, the CH3Cl emission rates increased with temperature following the Arrhenius relation. Activation energies were similar for all investigated plant species, indicating that even though emissions vary largely between plant species, their response to changing temperatures is similar. The chloride and methoxyl group contents of the leaf litter samples were determined, but those parameters were not significantly correlated to the CH3Cl emission rate. 相似文献
643.
644.
含镍三氯化铁蚀刻废液的综合利用 总被引:1,自引:0,他引:1
针对显像管荫罩生产工艺中产生的含镍三氯化铁蚀刻废液的处理,先用铁粉将 3价的铁还原,再以硫化亚铁将镍置换回收镍,而铁以液体三氯化铁或固体氯化亚铁的形式得到综合利用,处理工艺技术先进、简单有效,环境效益及经济效益显著。 相似文献
645.
Ali Deriszadeh Thomas G. Harding Maen M. Husein 《Process Safety and Environmental Protection》2008,86(4):244
The high demand for water in oil sands operations in addition to the shortage of fresh water resources mandate continuous search for reliable and cost effective water treatment technologies. Micellar-enhanced ultrafiltration (MEUF) is potentially applicable to produced water treatment. MEUF is, however, susceptible to membrane plugging and back contamination, especially at high surfactant dosages. Recent investigations showed that addition of small amounts of a non-ionic surfactant to an ionic surfactant solution reduces the critical micellar concentration (CMC) of the mixed surfactant solution, and consequently reduces the surfactant dosage required to achieve certain removal of contaminants using MEUF. In the present study a naphthenic acid, octanoic acid, typically existing in produced water is shown to play a similar role as the non-ionic surfactant when added to the cationic surfactant cetylpyridinium chloride (CPC). Cross-flow MEUF using three different molecular weight cutoffs (MWCOs) of polyacrylonitrile (PAN) hollow fiber membranes was used to treat synthetic produced water containing p-xylene. The mixed CPC/octanoic acid solution removed comparable percentages of p-xylene contaminant at much lower concentrations of CPC. Decreasing CPC concentration in the feed resulted in less fouling and higher permeate flux and reduced back contamination. This, in turn, enhanced the performance of MEUF. 相似文献
646.
聚合氯化铝锌絮凝剂的制备及其性能 总被引:4,自引:1,他引:3
用在AlCl,与ZnCl2溶液中加NaOH溶液的方法制备无机高分子絮凝剂聚合氯化铝锌(PAZC),通过正交实验确定的最佳制备条件为:反应时间10min、碱化度2.2、氯化铝浓度0.5mol/L、NaOH溶液浓度0.5mol/L。在n(Zn):n(Al)=0.6、水样pH=7.8、PAZC加入量为5mg/L的条件下,浊度和COD去除率分别为98.9%和88.2%。PAZC与聚合氯化铝对各种工业废水的处理效果比较结果表明,PAZC对各种工业废水的处理效果较好。从废水处理成本来看,PAZC具有较好的经济效益。 相似文献
647.
648.
为了快速准确测定可再生湿法烟气脱硫过程有机胺吸收液中的p(SO2-4),建立了以茜素红为指示剂,用BaCl2直接滴定测定有机胺吸收液中p(SO2-4)的方法.实验结果表明:当试样pH为4.0 ~4.5时,方法的相对误差为0.28%-0.62%,加标回收率均在97%以上;SO2-3的存在会使p(SO2-4)的测定结果偏大... 相似文献
649.
循环流化床灰制备聚合氯化铝铁絮凝剂 总被引:2,自引:1,他引:1
以煤矸石电厂循环流化床灰(CFB灰)为原料,采用酸浸、水解、聚合和熟化等工艺过程,制备聚合氯化铝铁(PAFC)絮凝剂产品。重点对制备PAFC絮凝剂的酸浸工艺参数进行研究,其最佳工艺条件为:盐酸浓度为20.2%、酸浸温度为110℃、酸浸时间为2 h、液固比为4∶1;Fe2O3浸出率为90.6%,Al2O3的浸出率为48.5%。同时采用实验得出的最优工艺参数进行了产品制备,并对产品进行了絮凝性能实验。结果表明,在相同条件下PAFC的絮凝效果明显好于聚合氯化铝(PAC),用CFB灰制备PAFC絮凝剂产品是可行的。 相似文献
650.