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211.
A method for rapidly determining potential H+ production by sulfide oxidation with H2O2 in mine-spoil materials has been tested. Measuring pH 6 h after the addition of the H2O2 in a 1:20 sample-solution (w/v) ratio, seems to be an adequate period for most of the samples. The method was applied to
spoil samples, being recommended as a measure of the potential of a material to acidify the environment, in the first steps
of characterization of the tailing's materials. The same procedure after grinding can also indicate the inherent ability to
neutralize the acidity. This will allow the selection of the most suitable materials to be mixed in the spoil with the sulfide-rich
ones, facilitating the later field work. 相似文献
212.
含硫污水处理方法综述 总被引:1,自引:1,他引:1
本文参考国内外文献及技术资料,较全面地论述了各种含硫污水处理方法的优缺点,供从事油气田污水处理的同志参考。 相似文献
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针对煤化行业高含氮焦化污水,采用厌氧氨氧化工艺进行脱氮污泥培养、驯化,对可能制约厌氧氨氧化菌生长的因素进行研究分析。结果发现:得出适宜于厌氧氨氧化污泥培养的水力停留时间、温度、p H及为保持污泥活性要求限制反应器进水氨氮和亚硝酸盐氮的最大负荷值。 相似文献
216.
Kay Grossmann Thuro Arnold Robin Steudtner Stefan Weiss Gert Bernhard 《Die Naturwissenschaften》2009,96(8):963-974
Low-temperature alteration reactions on uranium phases may lead to the mobilization of uranium and thereby poses a potential
threat to humans living close to uranium-contaminated sites. In this study, the surface alteration of uraninite (UO2) and uranium tetrachloride (UCl4) in air atmosphere was studied by confocal laser scanning microscopy (CLSM) and laser-induced fluorescence spectroscopy using
an excitation wavelength of 408 nm. It was found that within minutes the oxidation state on the surface of the uraninite and
the uranium tetrachloride changed. During the surface alteration process U(IV) atoms on the uraninite and uranium tetrachloride
surface became stepwise oxidized by a one-electron step at first to U(V) and then further to U(VI). These observed changes
in the oxidation states of the uraninite surface were microscopically visualized and spectroscopically identified on the basis
of their fluorescence emission signal. A fluorescence signal in the wavelength range of 415–475 nm was indicative for metastable
uranium(V), and a fluorescence signal in the range of 480–560 nm was identified as uranium(VI). In addition, the oxidation
process of tetravalent uranium in aqueous solution at pH 0.3 was visualized by CLSM and U(V) was fluorescence spectroscopically
identified. The combination of microscopy and fluorescence spectroscopy provided a very convincing visualization of the brief
presence of U(V) as a metastable reaction intermediate and of the simultaneous coexistence of the three states U(IV), U(V),
and U(VI). These results have a significant importance for fundamental uranium redox chemistry and should contribute to a
better understanding of the geochemical behavior of uranium in nature.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
217.
城市景观水体中腐殖酸的臭氧氧化去除 总被引:1,自引:0,他引:1
以南京师范大学德风园池底泥中提取的腐殖酸(HA)为研究对象,采用臭氧氧化技术对其进行去除,对初始pH值、混合气体流量、腐殖酸(HA)初始浓度以及水中常见离子等因素对去除效果的影响进行了研究。实验结果表明:腐殖酸(HA)的去除率随初始pH值的升高而提高,随混合气体流量减少而提高;当腐殖酸(HA)初始浓度为5 mg/L时,反应过程中溶液的UV254升高,紫外扫描结果发现,溶液在200~220 nm内出现杂乱的吸收峰,表明有新物质生成;水中常见的无机阴离子(CO32-、HCO3-)和二价金属离子(Ca2+、Cu2+)的存在会降低臭氧对腐殖酸(HA)的去除率。 相似文献
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Tianzeng Chen Yongchun Liu Biwu Chu Changgeng Liu Jun Liu Yanli Ge Qingxin M Jinzhu M Hong He 《环境科学学报(英文版)》2019,31(5):256-263
Current atmospheric quality models usually underestimate the level of ambient secondary organic aerosol(SOA), one of the possible reasons is that the precursors at different concentrations may undergo different oxidation processes and further affect SOA formation. Therefore, there is a need to perform more chamber studies to disclose the influence. In this work, SOA formation over a wide range of initial precursor concentrations(tens of ppb to hundreds of ppb levels) was investigated in a 30 m3 indoor smog chamber,and mainly through the analysis of multiple generations of VOCs detected from HR-To FPTRMS to expound the difference in the oxidation process between low and high precursor concentrations. Compared to high initial concentrations, gas-phase intermediates formed at low concentrations had a higher intensity by about one order of magnitude, and the lowvolatility compounds also had a higher formation potential due to the competition between semi-volatile intermediates and precursors with oxidants. In addition, the formed SOA was more oxidized with higher f44 value(0.14 ± 0.02) and more relevant to real atmosphere than that formed at high concentrations. This work should help to deeply understand SOA formation and improve the performance of air quality models for SOA simulation. 相似文献