全文获取类型
收费全文 | 484篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
综合类 | 3篇 |
化学工业 | 339篇 |
金属工艺 | 1篇 |
建筑科学 | 87篇 |
能源动力 | 3篇 |
轻工业 | 5篇 |
水利工程 | 7篇 |
石油天然气 | 2篇 |
一般工业技术 | 34篇 |
冶金工业 | 1篇 |
原子能技术 | 1篇 |
自动化技术 | 2篇 |
出版年
2020年 | 2篇 |
2019年 | 8篇 |
2018年 | 10篇 |
2017年 | 8篇 |
2016年 | 15篇 |
2015年 | 10篇 |
2014年 | 15篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 23篇 |
2010年 | 16篇 |
2009年 | 24篇 |
2008年 | 26篇 |
2007年 | 25篇 |
2006年 | 29篇 |
2005年 | 26篇 |
2004年 | 13篇 |
2003年 | 26篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 15篇 |
1999年 | 12篇 |
1998年 | 5篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 13篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 15篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1980年 | 7篇 |
排序方式: 共有485条查询结果,搜索用时 15 毫秒
51.
Occurrence and behavior of four of the most used sunscreen UV filters in a wastewater reclamation plant 总被引:2,自引:0,他引:2
Four UV filters, benzophenone-3 (BP-3), 4-methylbenzylidence camphor (4-MBC), ethylhexyl methoxycinnamate (EHMC), and octocrylene (OC), have been examined along the different units of a wastewater reclamation plant (WWRP) located in Tianjin, North China. The analytical procedure included solid-phase extraction and gas chromatographic/mass spectrometric analyses. All four UV filters were detected in the influent during the three sampling campaigns (February, July, and September), and the concentrations ranged from 34 to 2128 ng L(-1). The concentrations of the four UV filters were higher in hot weather (July and September) than in cool weather (February). The monthly average removal ranged from 7.6% to 21% for the selected UV filters during coagulation-flocculation (C-F) treatment. The ozonation treatment achieved the maximum removal (16-28%); on the contrary, the continuous microfiltration (CMF) achieved the lowest removal (3.6-8.2%). The total removal efficiencies along the plant varied from 28% to 43%. These results indicate that the UV filters are not completely removed during WWRP treatment and may be carried over into the environment during the reuse applications. 相似文献
52.
Activated carbon (AC) has been used to catalyze the ozonation of pyruvic acid in water. Pyruvic acid conversions were found to be 9 and 37% after 90 min of single ozonation and single adsorption with 40 gL?1 AC, respectively, while 82% was reached at the same conditions during the AC catalytic ozonation. Also, for similar conditions, mineralization reached values of 67% in the AC catalytic ozonation against hardly 5% in the non-catalytic experiment. The process likely develops through both adsorption of ozone and pyruvic acid on the AC surface and generation of hydroxyl radicals that eventually is the responsible oxidizing species. Rate constants for both non-catalytic ozonation and AC-Ozone catalytic surface reaction, at 20°C and pH 7.5, were found to be 0.025 min?1 and 87.9 Lg?1s?1, respectively. For AC concentrations higher than 2.5 gL?1 gas-liquid mass transfer of ozone constituted the limiting step. At lower concentrations, internal diffusion plus surface reaction controlled the process rate. 相似文献
53.
Ozonation is a widely used technology within the water industry. Bromate ion formed by oxidation of water containing bromide ion was studied with the Gas Ozone Test and Pilot Scale Ozonation. Bromate ion formation was investigated along with the removal of triazines and/or manganese. Under identical conditions of ozonation, BrO3 ? formation is specific for each water and depends on parameters such as Total Organic Carbon, UV absorbance at 254 nm, applied ozone and ozone residual. Pesticides degradation by ozonation alone cannot be achieved without the formation of BrO3 ? at a high concentration. Hydrogen peroxide, at a constant ozone dose, reduces the BrO3 ? formation. However, even with the use of hydrogen peroxide, the concentration of BrO3 ? can remain in excess of the provisional Maximum Contaminant Level (10 μg/L). For certain types of water, pesticide degradation is difficult to achieve if the MCL for BrO3 ? has to be met. Manganese oxidation by ozone appears to be achieved without high bromate formation; indeed the presence of manganese hinders BrO3 ? formation. 相似文献
54.
The reactivity of a series of fatty acids toward ozone was examined in aqueous solution at low substrate concentration (μg.L?1 range). Saturated fatty acids were unreactive, unsaturated fatty acids were readily consumed. A number of reaction products or their methylated derivatives were identified by gas chromatography and gas chromatography-mass spectrometry. The products identified are consistent with a 1,3-dipolar cyclo-addotion reaction. 相似文献
55.
56.
Bin Wang Chang-ping Zhu Run-hang Gong Jin Zhu Bo Huang Fei Xu Qing-gong Ren Qing-bang Han Zhen-bing He 《水科学与水工程》2015,8(3):233-238
The degradation of acephate in aqueous solutions was investigated with the ultrasonic and ozonation methods, as well as a combination of both. An experimental facility was designed and operation parameters such as the ultrasonic power, temperature, and gas flow rate were strictly controlled at constant levels. The frequency of the ultrasonic wave was 160 k Hz. The ultraviolet-visible(UV-Vis) spectroscopic and Raman spectroscopic techniques were used in the experiment. The UV-Vis spectroscopic results show that ultrasonication and ozonation have a synergistic effect in the combined system. The degradation efficiency of acephate increases from 60.6% to 87.6% after the solution is irradiated by a160 k Hz ultrasonic wave for 60 min in the ozonation process, and it is higher with the combined method than the sum of the separated ultrasonic and ozonation methods. Raman spectra studies show that degradation via the combined ultrasonic/ozonation method is more thorough than photocatalysis. The oxidability of nitrogen atoms is promoted under ultrasonic waves. Changes of the inorganic ions and degradation pathway during the degradation process were investigated in this study. Most final products are innocuous to the environment. 相似文献
57.
Sánchez-Polo M Rivera-Utrilla J Prados-Joya G Ferro-García MA Bautista-Toledo I 《Water research》2008,42(15):4163-4171
The main objective of this study was to analyze the effectiveness of technologies based on the use of ozone and activated carbon for the removal of nitroimidazoles from water, considering them as model of pharmaceutical compounds. A study was undertaken of the influence of the different operational variables on the effectiveness of each system studied (O(3), O(3)/activated carbon), and on the kinetics involved in each process. Ozone reaction kinetics showed that nitroimidazoles have a low reactivity, with [Formula: see text] values <350M(-1)s(-1) regardless of the nitroimidazole and solution pH considered. However, nitroimidazoles have a high affinity for HO radicals, with radical rate constant (k(HO)) values of around 10(10)M(-1)s(-1). Among the nitroimidazole ozonation by-products, nitrate ions and 3-acetyl-2-oxazolidinone were detected. The presence of activated carbon during nitroimidazole ozonation produces (i) an increase in the removal rate, (ii) a reduction in the toxicity of oxidation by-products, and (iii) a reduction in the concentration of dissolved organic matter. These results are explained by the generation of HO radicals at the O(3)-activated carbon interface. 相似文献
58.
Ivan Stankovic 《臭氧:科学与工程》1992,14(2):101-121
Ozone currently is being used in several drinking water treatment plants in Yugoslavia. The new Belgrade water treatment plant “Makis” is the largest one with 42 kg/h of installed ozone generating capacity and has been in operation since 1987. This paper describes the main features of ozone application in drinking water treatment. The experimental results of “Makis” pilot-plant investigations and a few examples of ozone application in Yugoslavia are presented. 相似文献
59.
Different UVA radiation and advanced oxidation systems, most of them involving ozone, have been applied to remove mixtures of three contaminants of pharmaceutical type: diclofenac (DCF), sulfamethoxazole (SMT) and caffeine (CFF), both in ultrapure and secondary treated wastewater. The influence of the water matrix has been studied in terms of individual compound concentration and TOC removal. Also, biodegradability of the treated wastewater before and after the advanced oxidation process, as BOD/COD ratio, the partial oxidation yield, the increment of average state of carbon oxidation and ozone consumption have been determined. For mgL?1 to 100 μgL?1 concentrations and regardless of the ozone process and water type, DCF and SMT are removed in less than 10 min mainly by direct reaction with ozone, especially in the case of DCF. CFF, on the contrary, is mainly removed through hydroxyl radicals. For lower concentration (≤100 μgL?1), DCF still disappears by direct ozonation, CFF by hydroxyl radicals oxidation and SMT through both direct ozonation and hydroxyl radical oxidation. Once DCF and SMT have disappeared, TOC is removed by reacting with hydroxyl radicals, regardless of the water matrix. Photocatalytic ozonation allows the highest TOC degradation rate, partial oxidation yield, increment of average state of carbon oxidation and biodegradability together to the lowest ozone consumption per mg TOC eliminated. 相似文献
60.
P.E. Domenic Grasso 《臭氧:科学与工程》1987,9(2):109-124
The formation of potentially carcinogenic organic halides has been shown to result from drinking water disinfection with chlorine. xidative treatment of organic halide precursors with ozone prior to chlorination has surfaced as an attractive technique for reducing the formation of these compounds. In addition to reduction of precursor levels, preozonation has been reported to effect other beneficial results in water treatment. This paper presents design methodologies to optimize the implementation of the ozonation process for water treatment applications. Pre-design considerations common to all ozonation design processes are discussed. Subsequently, design procedures for the ozone generation and contacting systems are reviewed. 相似文献