全文获取类型
收费全文 | 2068篇 |
免费 | 284篇 |
国内免费 | 1361篇 |
专业分类
安全科学 | 150篇 |
废物处理 | 312篇 |
环保管理 | 160篇 |
综合类 | 2199篇 |
基础理论 | 241篇 |
污染及防治 | 614篇 |
评价与监测 | 31篇 |
社会与环境 | 4篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 1篇 |
2023年 | 53篇 |
2022年 | 83篇 |
2021年 | 108篇 |
2020年 | 99篇 |
2019年 | 98篇 |
2018年 | 107篇 |
2017年 | 100篇 |
2016年 | 119篇 |
2015年 | 143篇 |
2014年 | 155篇 |
2013年 | 192篇 |
2012年 | 254篇 |
2011年 | 208篇 |
2010年 | 164篇 |
2009年 | 203篇 |
2008年 | 117篇 |
2007年 | 235篇 |
2006年 | 245篇 |
2005年 | 176篇 |
2004年 | 141篇 |
2003年 | 136篇 |
2002年 | 118篇 |
2001年 | 91篇 |
2000年 | 89篇 |
1999年 | 59篇 |
1998年 | 52篇 |
1997年 | 36篇 |
1996年 | 26篇 |
1995年 | 24篇 |
1994年 | 16篇 |
1993年 | 21篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3713条查询结果,搜索用时 31 毫秒
971.
改性半焦烟气脱硫的机理研究 总被引:10,自引:0,他引:10
本文对海拉尔褐煤半焦及其水蒸气活化和高温氧化改性后的烟气脱硫性能进行了研究。 相似文献
972.
The influence of lubricants, UV stabilizers, antioxidants, and metal deactivators on the resistance of ABS to thermal oxidation was studied by means of the chemiluminescence technique. Neither of the additives seems to affect significantly the induction period of oxidation. At the same time, the influence of various additives on the oxidation rate constant is remarkably different: the introduction of lubricants and UV stabilizers increases its value, while antioxidants and metal deactivators have the opposite effect. For the particular systems studied durability is decreased in samples containing the lubricant and UV stabilizers and increased in samples stabilized with the antioxidant and metal deactivator. 相似文献
973.
The thermal oxidative stability of various ABS/PC compounds was studied by means of the chemiluminescence technique. Similarly to pure ABS, Irganox 1076 and Irganox MD 1024 perform as moderate antioxidants in ABS/PC and (ABS/PC + lubricant) blends. Neither Tinuvin 144, Irgaphos 168, nor their mixture affects the durability of the ABS/PC blend. At the same time, (Irgaphos 168 + Tinuvin 144) in combination with Irganoxes was found to provide a noticeable enhancement in durability to the (ABS/PC + lubricant) system. Titanium dioxide pigments by themselves have only a slight influence on the oxidative stability of the ABS/PC blend. Durability of the (ABS/PC + pigment) and (ABS/PC + lubricant) systems was found to be the same and the overall protective effect of Irganox 1076 was similar in both the (ABS/PC + lubricant) and the (ABS/PC + lubricant + pigment) systems. Certain modifiers significantly improve the durability of the ABS/PC compounds, although their function may differ in the systems with and without pigments.Guest Editor: Dr. Graham Swift, Rohm & Haas. 相似文献
974.
975.
The concentration of water-soluble organic nitrogen (WSON) in precipitation has been measured at seven sites across the United Kingdom, over a period of 1–2 years, using protocols developed in a pilot study. Samples were collected over 1–2 weeks in continuously open funnels made of stainless steel, draining to a glass bottle, and were preserved during and after collection by the addition of thymol. After chemical analysis, samples were excluded from the long-term average if they showed signs of contamination (significant concentrations of K+ or PO4
3–). Two methods of measuring total dissolved N were used, persulphate oxidation and high-temperature chemiluminescence. The latter generally gave the larger values, and has been used to asses the organic component of dissolved N. The long-term data set confirms the original results from the pilot study - organic N contributes between 24 and 40% to the total annual wet deposition of dissolved N across the United Kingdom. The fraction of WSON was greatest at western sites, and was strongly correlated with ammonium concentrations. However, the seasonal pattern across all sites showed a late spring maximum for ammonium and nitrate, but a late summer maximum for WSON. The magnitude of the contribution of WSON to wet-deposited N has implications for the setting and assessment of critical loads for N deposition. 相似文献
976.
977.
978.
979.
Zerbinati O Pittavino S 《Environmental science and pollution research international》2003,10(6):395-398
BACKGROUND AND INTENTION: Aromatic sulphonates other than surfactants and their hydroxy and amino-derivatives are important intermediates for the production of azo dyes. Their production on a large scale can be detrimental for the environment, if the by-products of their synthesis are not disposed of appropriately. An industrial waste, the organic components of which were mainly amino and hydroxy-substituted aromatic sulphonates, seriously endangers the environment close to an dismissed Italian industrial site. Inorganic sulphates and chlorides contained in the waste seriously hinder its disposal by incineration, since they corrode furnace walls. In this work, preliminary exploration of aqueous-phase electrochemically and photochemically induced oxidation techniques have been performed as possible alternatives to incineration. METHODS: Electrochemically-induced oxidation was experimented on individual aromatic sulphonates and on an industrial waste by electrolysing them between smooth platinum electrodes at low temperature (5 degrees C) and high current densities (0.4 A/cm2) with aqueous 0.5 M NaHSO4 electrolyte. Photochemically-induced oxidation was performed by irradiating individual aromatic sulphonates or industrial waste with a 500 W mercury lamp in the presence of sodium peroxydisulphate. RESULTS AND DISCUSSION: After 200 min electrodegradation, 90% of the original compounds disappeared, while 50% Total Organic Carbon (TOC) of an industrial waste was removed from solution after 10 hours. After 180 min UV-photodegradation, 90% of two test aromatic sulphonates disappeared, while 65% of TOC of industrial waste was removed after 5 hours. CONCLUSIONS: Two methods, electrochemical and UV-persulphate oxidation of an industrial waste, were used in order to propose a disposal procedure alternative to incineration. Electrodegradation with smooth Pt anode in 0.5 M NaHSO4 at 5 degrees C halved TOC concentration within 10 hours, while persulphate-assisted UV-photochemical oxidation with a 500 W high pressure Hg lamp abated two-thirds of TOC concentration after 5 hours. Energetic consumption of electrodegradation was 0.33 kWh/g TOC, while that of photooxidation was larger than 2 kWh/g TOC. Although both techniques can be considered efficient from a purely chemical point of view, since both are capable of wet-oxidising the aromatic sulphonates and the industrial waste, electrodegradation seems more promising than a photochemical degradation if economical considerations are also taken into account. Considering also that neither cell design nor catalyst were optimised in this preliminary study, the energy yield of electrodegradation seems likely to be largely improved. 相似文献
980.
Aniline degradation by electrocatalytic oxidation 总被引:4,自引:0,他引:4
The degradation of aniline solution in alkaline medium of pH 11.0 by electrocatalytic oxidation has been studied using an electrochemical reactor containing a SnO2–Sb2O3–PtO anode and a Ti cathode, both of 54 cm2 area. Hydroxyl radicals (HO√) are produced at the anode, being tested with the trace catcher salicylic acid and phenol by spectrophotometery and high performance liquid chromatography. Intermediates dianiline, 4-anilino phenol and azobenzol were detected by gas chromatography–mass spectrometry. The existence of HO√ produced in the aniline degradation was assayed with scavenger tertiary butanol. The results showed that electrocatalytic oxidation is an effective process for the degradation of aniline. A general reaction pathway that accounts for aniline degradation to CO2 involving those intermediates is proposed. 相似文献