全文获取类型
收费全文 | 7725篇 |
免费 | 1062篇 |
国内免费 | 2539篇 |
专业分类
安全科学 | 1038篇 |
废物处理 | 180篇 |
环保管理 | 711篇 |
综合类 | 5970篇 |
基础理论 | 1238篇 |
污染及防治 | 719篇 |
评价与监测 | 615篇 |
社会与环境 | 530篇 |
灾害及防治 | 325篇 |
出版年
2024年 | 54篇 |
2023年 | 174篇 |
2022年 | 480篇 |
2021年 | 450篇 |
2020年 | 544篇 |
2019年 | 389篇 |
2018年 | 380篇 |
2017年 | 445篇 |
2016年 | 368篇 |
2015年 | 513篇 |
2014年 | 502篇 |
2013年 | 681篇 |
2012年 | 691篇 |
2011年 | 716篇 |
2010年 | 618篇 |
2009年 | 559篇 |
2008年 | 533篇 |
2007年 | 570篇 |
2006年 | 559篇 |
2005年 | 462篇 |
2004年 | 328篇 |
2003年 | 236篇 |
2002年 | 245篇 |
2001年 | 214篇 |
2000年 | 193篇 |
1999年 | 105篇 |
1998年 | 74篇 |
1997年 | 51篇 |
1996年 | 37篇 |
1995年 | 48篇 |
1994年 | 27篇 |
1993年 | 15篇 |
1992年 | 23篇 |
1991年 | 13篇 |
1990年 | 11篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1972年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 640 毫秒
961.
962.
以金霉素为降解对象,采用沉淀法制备α-FeOOH光催化剂,进一步将其用共价结合法负载在陶瓷膜上,用SEM、XRD、EDS、UV-Vis和FTIR对α-FeOOH和光催化陶瓷膜进行表征.结果表明催化剂α-FeOOH呈针状或纺锤长片状,长宽分别为500~550nm、25~50nm,经α-FeOOH改性的陶瓷膜孔隙率由14.83%变为8.11%.研究光芬顿陶瓷膜耦合体系对金霉素的降解效率和动力学行为,确定了光芬顿陶瓷膜耦合体系的最优降解条件为金霉素初始浓度50mg/L,H2O2投加浓度10mmol/L,UV强度为3796.6μW/cm2.进一步利用UV-Vis光谱分析了两种体系对金霉素的降解机理,光催化剂体系下,H2O2的浓度基本保持不变,而光芬顿陶瓷膜耦合体系下H2O2的浓度先升后降,同时后者在同一时间点对TOC和NH4+-N去除率更高,表明光芬顿陶瓷膜耦合体系氧化能力更强,对金霉素的降解更为彻底. 相似文献
963.
964.
阴离子表面活性剂是环境中分布广泛且具有代表性的一类有机污染物。采用分置式膜生物反应器(MBR)进行去除模拟废水中阴离子表面活性剂(LSS)的实验.结果表明:MBR对阴离子表面活性剂的去除率高于90%。同时考察了阴离子表面活性剂生物降解的影响因素,确定其适宜降解蒂件为:气体流量为0.3m^3/h、活性污泥浓度为6948mg/L。初步探计了降解动力学和降解机理,研究表明对阴离子表面活性剂的去除符合拟一级反应动力学过程,且生物降解对其去除起主要作用。 相似文献
965.
Preparation and characterization of visible-light-active nitrogen-doped TiO2 photocatalyst 总被引:4,自引:0,他引:4
A visible-light photocatalyst was prepared by calcination of the hydrolysis product of Ti(SO4)2 with ammonia as precipitator. The color of this photocatalyst was vivid yellow. It could absorb light under 550 nm wavelength. The crystal structure of anatase was characterized by XRD. The structure analysis result of X-ray fluorescence(XRF) shows that doped-nitrogen was presented in the sample. The photocatalytic activities were evaluated using methyl orange and phenol as model pollutants. The photocatalytic activities of samples were increasing gradually with calcination temperature from 400℃ to 700℃ under UV irradiation. It can be seen that the degradation of methyl orange follows zero-order kinetics. However, the calcination temperatures have no significant influence on the degradation of phenol under sunlight. The N-doped catalyst shows higher activity than the bare one under solar irradiation. 相似文献
966.
967.
Fate and assessment of persistent organic pollutants in water and sediment from Minjiang River Estuary,Southeast China 总被引:56,自引:0,他引:56
Persistent organochlorine compounds were analyzed in surface water, porewater and surficial sediment samples from Minjiang River Estuary, which is the first large river in Fujian Province, Southeast of China. The total concentrations of 18 organochlorine pesticides were 214.4-1819, 4541-13,699 ng/l, 28.79-52.07 ng/g in surface water, porewater and sediments (dry weight) respectively, and those of 21 polychlorinated biphenyls (PCBs) in the three phases were: 203.9-2473, 3192-10,855 ng/l, 15.14-57.93 ng/g respectively. The results showed that the concentrations of these selected organochlorine pesticides and PCBs in porewater were higher than those in surface water. It may be due to the fact that these organic hydrophobic pollutants tend to stay in the sediments, and then re-suspend from the sedimentary phase to the upper water. We have analyzed the distribution characteristics of individual organochlorine pesticide components and PCBs, and found that alpha-HCH, DDE, Heptachlor, Endosulfan II, Methoxychlor were the most common organochlorine pesticides contaminants. Considering the groups of HCHs (HCHs=alpha-HCH+beta-HCH+gamma-HCH+delta-HCH) and DDTs (DDTs=DDT+DDD+DDE), the predominance of beta-HCH, DDE in all water, porewater and sediment samples was clearly observed. This observation suggested that beta-HCH was resistant to biodegradation and the DDTs had been transformed to its metabolites, DDE and DDD, of which DDE that was more un-degradable. The PCB congeners containing 3-6 chlorines had the great preponderance in the three phase. These results were compared with those present in other estuaries and harbors. A risk assessment was evaluated for the persistent organic pollutants in the Minjiang River Estuary. 相似文献
968.
969.
Hexavalent chromium [Cr(VI)] in the form of potassium dichromate was photochemically reduced to trivalent chromium [Cr(III)] in aqueous solutions containing glycerol. This reaction occurred rapidly during irradiation with either unfiltered sunlight or a UVA-emitting light source. Photochemical reduction of Cr(VI) was pH-dependent and did not occur in dilute solutions of sodium hydroxide. In acidified solutions, the reduction occurred at elevated rates and at lower concentrations of glycerol. This reaction was found to be dependent on the unsubstituted alcohol groups of glycerol since alpha-phosphoglycerol and beta-phosphoglycerol did not support the photochemical reduction of Cr(VI). These findings suggest that glycerol or related polyols can be used for the remediation of hexavalent (toxic) chromium at contaminated environmental sites. 相似文献
970.