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131.
施悦  任南琪  章育铭  肖荣新 《环境科学》2007,28(11):2515-2519
通过小试研究,利用气-质联机(GC-MS)对黄芩甙的厌氧生物降解曲线和途径进行了探讨,对黄芩甙的降解数据进行趋势化模拟和线性回归分析,得到了相应的降解动力学方程.黄芩甙可能的降解途径为“脱糖→脱苯→开环→饱和化→拆链”,降解时间需47 h以上, 厌氧分解的主要产物是小分子氧化物,如醇、醛、酸、酯、烯烃以及还原态饱和烷烃.结果表明,黄芩甙降解的限速步骤在水解酸化阶段,适宜采用两相厌氧消化技术和较长的停留时间进行处理.  相似文献   
132.
环境中灭幼脲类农药的监测方法及其迁移转化情况   总被引:4,自引:0,他引:4       下载免费PDF全文
综述了环境中灭幼脲类农药的各种监测分析方法,并对各种监测分析方法的优缺点作了评述;同时,总结了灭幼脲类农药在环境中的迁移情况和各种降解途径,分析了影响其降解情况的各种因素。   相似文献   
133.
采用典型产氢途径的丁酸梭菌和阴沟肠杆菌作为对比菌株,铁元素作为限制性因子,研究Ethanoligenens sp.B49的产氢代谢过程对铁的依赖性以及产氢机制.铁限制性培养结果表明,与完全培养条件相比,在铁浓度限制在2 mg·L-1条件下B49仍保持很好的生长状态和产氢性能,其产氢不受铁元素不足的影响,即其产氢行为不具有铁依赖性;这一性质与梭菌型产氢途径的丁酸梭菌表现出相似的规律,完全区别于阴沟肠杆菌铁依赖型的产氢机制.初步判断高效产氢菌B49的产氢代谢途径类似于梭菌型产氢途径.  相似文献   
134.
The photocatalytic degradation of dye Rhodamine B (RhB) in the presence of TiO2 nanostdpe or P25 under visible light irradiation was investigated. The degradation intermediates were identified using Infrared spectra (IR spectra), ^1H nuclear magnetic resonance (^1HNMR) spectra, and gas chromatography-mass spectroscopy (GC-MS). The IR and the ^1HNMR results showed that the large conjugated chromophore structure of RhB was efficiently destroyed under visible light irradiation in both the photocatalytic systems (TiO2 nanostfipe or P25 and Rhodamine B systems). GC-MS results showed that the main identified intermediates were ethanediotic acid, 1,2-benzenedicarboxylic acid, 4-hydroxy benzoic acid and benzoic acid, which were almost the same in the TiO2 nanostdpes and P25 systems. This work provides a good insight into the reaction pathway(s) for the TiO2-assisted photocatalytic degradation of dye pollutants under visible light irradiation.  相似文献   
135.
环境雌激素及其降解途径   总被引:1,自引:4,他引:1  
结合近期国内外以及作者对环境雌激素降解的研究,指出环境雌激素可以通过多种途径迁移、降解,环境雌激素主要降解途径为生物降解和光解;一般情况下多数不易降解,易富集,研究其降解具有重要的意义。  相似文献   
136.
Quantification of regulated and emerging disinfection byproducts (DBPs) in swimming pool water, as well as the assessment of their lifetime health risk are limited in China. In this study, the occurrence of regulated DBPs (e.g., trihalomethanes, haloacetic acids) and emerging DBPs (e.g., haloacetonitriles, haloacetaldehydes) in indoor swimming pool water and the corresponding source water at a city in Eastern China were determined. The concentrations of DBPs in swimming pool water were 1-2 orders of magnitude higher than that in source water. Lifetime cancer and non-cancer risks of DBPs stemming from swimming pool water were also estimated. Inhalation and dermal exposure were the most significant exposure routes related to swimming pool DBP cancer and non-cancer risks. For the first time, buccal and aural exposure were considered, and were proven to be important routes of DBP exposure (accounting for 17.9%-38.9% of total risk). The cancer risks of DBPs for all swimmers were higher than 10−6 of lifetime exposure risk recommended by United States Environmental Protection Agency, and the competitive adult swimmers experienced the highest cancer risk (7.82 × 10−5). These findings provide important information and perspectives for future efforts to lower the health risks associated with exposure to DBPs in swimming pool water.  相似文献   
137.
王勇  王颖 《中国环境科学》2019,39(10):4444-4455
基于能源结构优化视角对中国实现碳强度和碳峰值"双控"目标的可行性及最优路径进行分析.首先构建马尔科夫链和多目标优化模型,分别从自然演进、政策约束和成本约束角度预测能源消费结构;其次,将3种能源消费结构情景与3种经济发展情景结合,共得到9种综合情景下碳强度和碳峰值预测结果,判定各情景实现"双控"目标的可行性;最后,采用多属性决策模型分析"双控"目标的最优路径.结果表明,9种情景下,中国均可实现2020年和2030年的碳强度目标;然而,并非所有情景都能实现2030年碳排放达峰目标,经济发展速度与实现碳排放达峰目标的难易程度成反比.经济中速发展及减排政策约束下的能源结构调整情景是实现"双控"目标的最优路径,减排政策是"双控"目标顺利实现的关键所在.  相似文献   
138.
This paper presents the collected data concerning First Trimester Prenatal Diagnosis of Metabolic Diseases performed in different countries of the European Community by enzymatic methods using chorionic villi. In all, 258 diagnoses were made for 38 different metabolic diseases and 56 (22 per cent) affected fetuses have been detected. Several difficulties were encountered with regard to chorionic villus material or enzyme expression in this tissue. We stress the conditions necessary for avoiding errors in diagnosis.  相似文献   
139.
The performances and kinetic parameters of Fenton oxidation of 2,4- and 2,6-dinitrotoluene (DNT) in water-acetone mixtures and explosive contaminated soil washing-out solutions were investigated at a laboratory scale. The experimental results show that acetone can be a significant hydroxyl radical scavenger and result in serious inhibition of Fenton oxidation of 2,4- and 2,6-DNT. Although no serious inhibition was found in contaminated soil washing-out solutions, longer reaction time was needed to remove 2,4- and 2,6-DNT completely, mainly due to the competition of hydroxyl radicals. Fenton oxidation of 2,4- and 2,6-DNT fit well with the first-order kinetics and the presence of acetone also reduced DNT’s degradation kinetics. Based on the comparison and matching of retention time and ultraviolet (UV) spectra between high performance liquid chromatography (HPLC) and standards, the following reaction pathway for 2,4-DNT primary degradation was proposed: 2,4-DNT → 2,4-dinitro-benzaldehyde → 2,4-dinitrobenzoic acid → 1,3-dinitrobenzene → 3-nitrophenol.  相似文献   
140.
建立自下而上的综合动态优化模型,在节能、大气污染物(SO2、NOx和PM2.5)减排和节水的综合约束下,研究京津冀地区2015~2030年钢铁行业48项节能减排技术优化发展路径,并预测该地区钢铁行业能耗、大气污染物排放和水耗.结果表明,国家应优先鼓励推广干熄焦,小球烧结技术等22项技术,此类技术可以有效协同控制能耗、大气污染物排放和水耗.京津冀地区钢铁行业具有很大的节能、大气污染物减排和节水潜力,到2030年在实现大量节能、大气污染物减排潜力的同时可以实现节水10.08亿m3.虽然计算得到的购水成本仅约占总成本的2%,但是京津冀地区面临着严重大气污染和极度的水资源短缺问题,仍然需要兼顾节能减排技术对水资源的影响.  相似文献   
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