全文获取类型
收费全文 | 1211篇 |
免费 | 61篇 |
国内免费 | 426篇 |
专业分类
安全科学 | 61篇 |
废物处理 | 84篇 |
环保管理 | 99篇 |
综合类 | 615篇 |
基础理论 | 221篇 |
污染及防治 | 458篇 |
评价与监测 | 73篇 |
社会与环境 | 47篇 |
灾害及防治 | 40篇 |
出版年
2024年 | 4篇 |
2023年 | 11篇 |
2022年 | 49篇 |
2021年 | 39篇 |
2020年 | 30篇 |
2019年 | 48篇 |
2018年 | 40篇 |
2017年 | 53篇 |
2016年 | 54篇 |
2015年 | 86篇 |
2014年 | 103篇 |
2013年 | 129篇 |
2012年 | 108篇 |
2011年 | 100篇 |
2010年 | 90篇 |
2009年 | 73篇 |
2008年 | 108篇 |
2007年 | 82篇 |
2006年 | 61篇 |
2005年 | 53篇 |
2004年 | 50篇 |
2003年 | 46篇 |
2002年 | 39篇 |
2001年 | 29篇 |
2000年 | 26篇 |
1999年 | 29篇 |
1998年 | 26篇 |
1997年 | 22篇 |
1996年 | 22篇 |
1995年 | 16篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1977年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有1698条查询结果,搜索用时 890 毫秒
421.
Katrin Wendt-Potthoff René Frömmichen Peter Herzsprung Matthias Koschorreck 《Water, Air, & Soil Pollution: Focus》2002,2(3):81-96
To elucidate the role of Fe(III) reduction in mining lake sediments amended with organic substrates, we performed a large (10 m diameter) enclosure experiment in which sediments were amended with Carbokalk, a waste product from sugar industry containing organic carbon and lime. Fe(III) reduction rates were determined monthly by measuring the accumulation of Fe(II) in the sediments in the field. Fe(III) reduction rates were also determined by incubating sediment samples with synthetic Fe(III) oxyhydroxide under in situ temperature in the laboratory. Sulfate reduction was selectively inhibited in the Fe(III) reduction experiments by addition of sodium molybdate. Sulfate reduction was measured by accumulation of reduced inorganic sulfides in the field and by 35S radiotracer using a core injection technique. Sediment incubation and determination of sulfate reduction rates with radiotracer showed that sulfate reduction and direct microbial Fe(III) reduction occured simultaneously in the upper centimeters of the sediments and that both processes contributed to alkalinity generation. However, Fe(III) reduction was the initial process and rates were at least 3.5 fold higher than sulfate reduction rates. The results indicate that the presence of suitable anions for Fe(II) precipitation as carbonate or sulfide is needed in order to prevent loss of potential alkalinity by Fe(II) diffusion and reoxidation in the water column. 相似文献
422.
黄土高原地区石油类非点源污染试验研究 总被引:1,自引:0,他引:1
石油类非点源污染基本特征为污染源分散、污染源作用周期长、暴雨时易于形成高含沙水流以及由此引发的高强度石油类污染。试验结果表明,随土壤石油污染强度的提高,径流量增大,产沙量降低,但水、固两相中的污染物径流污染强度均增大。试验条件下,径流过程释放于水相中的石油类浓度可高达4~7 mg/L。 相似文献
423.
国外石油天然气开采行业清洁生产技术发展动态 总被引:1,自引:5,他引:1
对比和分析了各国或国际组织关于清洁生产含义的不同解释方法,阐述了石油天然气开采行业清洁生产的基本概念。在此基础上,按照物探、钻井、井下作业(包括试油、酸化及酸压、压裂、修井)、采油及采气生产几个工艺环节,对国际上石油天然气开采行业清洁生产最新技术进行了详细总结和分析。针对我国相关行业的清洁生产水平,提出了实用有效的技术发展对策和建议。 相似文献
424.
ABSTRACT: Customarily, it has been assumed that hydraulic conductivity is a stationary, homogeneous stochastic process with a finite variance for stochastic analysis of solute transport in the subsurface. That the distribution of hydraulic conductivity may have a fractal behavior with long range correlations was suggested from field data analyses. This motivates us to further investigate how the fractal behavior of permeability distribution impacts solute transport in porous media. This study provides longitudinal and transverse macrodispersivity coefficients and the variance of the solute concentration. Longitudinal and transverse macrodispersivity coefficients are found to depend strongly on the fractal dimension (D) of logarithmic hydraulic conductivity (logK). The longitudinal and transverse macrodispersivity coefficients are the highest when D = 1, and the values decrease monotonically to zero at D = 2. Both coefficients correspond to the characteristic length scale of the logK distribution, thus are scale dependent parameters. The ratio of the transverse to the longitudinal macrodispersivity coefficient is on the order of 10‐1 to 10‐4. Concentration variance also decreases with the fractal dimension of logK. There is no spatial spreading of solute for D = 2, and the concentration variance reaches zero for this case. 相似文献
425.
采用现场调研、取样、理化检测和分析的方法 ,以掌握铁路旅客列车垃圾中重金属含量水平 ,垃圾中主要污染元素和主要污染物有关的数据和信息 ;在调查和综合分析的基础上 ,提出铁路旅客列车垃圾重金属污染的防治对策 ,为有效地处理铁路旅客列车垃圾提供了科学依据 相似文献
426.
427.
On the basis of continuous tests and batch tests, conversion regular patterns of acetate, propionate and butyrate in activated sludge at different heights of the UASB reactor were conducted. Results indicated that the conversion capacity of the microbe is decided by the substrate characteristic when sole VFA is used as the only substrate. But when mixed substrates are used, the conversion regulations would have changed accordingly.Relationships of different substrates vary according to their locations. In the whole reactor, propionate‘s conversion is restrained by acetate and butyrate of high concentration. On the top and at the bottom of the reactor, conversion of acetate, but butyrate, is restrained by propionate. And in the midst, acetate‘s conversion is accelerated by propionate while that of butyrate is restrained. It is proved, based on the analysis of specific conversion rate, that the space distribution of the microbe is the main factor that affects substrates‘ conversion. The ethanol-type fermentation of the acidogenicophase is the optimal acid-type fermentation for the two-phase anaerobic process. 相似文献
428.
用化学还原法合成了纳米Co-B-P非晶态合金,用电感耦合等离子体光谱(ICP)、X射线粉末衍射(XRD)、透射电子显微镜(TEM)和差热分析(DSC)等手段对其进行了物性表征,并用微型催化反应装置考察了其对PH_3分解的催化作用。结果表明,非晶态合金Co-B-P对PH_3的分解具有良好的催化作用。在420℃分解率达到85%, 480℃达97%,500℃达100%,而且温度继续升高至600℃,分解率没有下降趋势,说明催化剂有比较高的热稳定性。 相似文献
429.
煤矿企业清洁生产效益模糊综合评价研究 总被引:1,自引:0,他引:1
煤矿企业推行并坚持实施清洁生产的动力是效益。但这一效益究竟如何,成为亟待研究的科学问题。本文运用模糊评价法开展对该问题的试探性研究。从经济、环境、社会效益3个方面选用18个评价指标,构成煤矿企业清洁生产效益评价指标体系,运用层次分析法确定指标权重系数并建立模糊综合评价模型,并进行了应用实例评估,最后用具体数值量化了实施清洁生产后的煤矿企业综合效益情况,得到解决问题的初步结论。 相似文献
430.