全文获取类型
收费全文 | 5146篇 |
免费 | 325篇 |
国内免费 | 2066篇 |
专业分类
安全科学 | 381篇 |
废物处理 | 311篇 |
环保管理 | 375篇 |
综合类 | 3052篇 |
基础理论 | 891篇 |
环境理论 | 2篇 |
污染及防治 | 1847篇 |
评价与监测 | 241篇 |
社会与环境 | 177篇 |
灾害及防治 | 260篇 |
出版年
2024年 | 14篇 |
2023年 | 98篇 |
2022年 | 252篇 |
2021年 | 245篇 |
2020年 | 202篇 |
2019年 | 173篇 |
2018年 | 207篇 |
2017年 | 258篇 |
2016年 | 239篇 |
2015年 | 311篇 |
2014年 | 408篇 |
2013年 | 561篇 |
2012年 | 438篇 |
2011年 | 431篇 |
2010年 | 375篇 |
2009年 | 348篇 |
2008年 | 345篇 |
2007年 | 296篇 |
2006年 | 279篇 |
2005年 | 192篇 |
2004年 | 142篇 |
2003年 | 181篇 |
2002年 | 186篇 |
2001年 | 153篇 |
2000年 | 149篇 |
1999年 | 148篇 |
1998年 | 153篇 |
1997年 | 116篇 |
1996年 | 113篇 |
1995年 | 121篇 |
1994年 | 104篇 |
1993年 | 70篇 |
1992年 | 65篇 |
1991年 | 46篇 |
1990年 | 41篇 |
1989年 | 24篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 3篇 |
排序方式: 共有7537条查询结果,搜索用时 203 毫秒
861.
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
862.
以钛酸四丁酯为原料 ,膨胀珍珠岩为载体 ,用溶胶 -凝胶法制备可漂浮于水面的负载型TiO2 。利用该负载型TiO2 对罗丹明B(RB)进行光催化脱色实验 ,结果表明 ,浸渍 3次的负载型TiO2 光催化活性最高 ,催化剂最佳用量为 5 0 0mg/10 0mLRB ,经 5h光照 ,对 10 0mL浓度为 1mg/L和 2 .5mg/LRB脱色率分别为 76 .6 7%和 4 7.2 7% ;该催化剂使用寿命长 ,2 5h后催化剂脱色性能没有减弱 ,可重复使用 ;经 8h光照 ,染料废水脱色效果好。 相似文献
863.
A pot experiment was conducted to appraise the hazards of bound residues of metsulfuron-methyl in soil at six levels (0, 0.050, 0.089, 0.158, 0.281, and 0.500 mg kg(-1)) to the growth of four rice varieties (Xiushui 63, Eryou 810, Liangyoupeijiu, and Zhenong 952). The morphological characteristics of rice roots like root number, total length, surface area of rice roots, and rice biomass were determined. The results showed that the bound residues of metsulfuron-methyl in soil impacted the growth of rice. Root number, total length of roots, surface area of roots, and biomass were restrained by bound residues of metsulfuron-methyl in soil. The inhibition rate of root growth increased from 69.46-81.32% to 85.18-95.97% with the increasing of levels of bound residues of metsulfuron-methyl from 0.05 mg kg(-1) to 0.50 mg kg(-1). The number of rice roots could be taken as a sensitive index to screen the rice varieties endurable to bound residues of metsulfuron-methyl in soil and to predict the potential hazards of bound residues of metsulfuron-methyl in soil to rice. The level of bound residues of metsulfuron-methyl in soil causing the root numbers decreased by 50% (IC50) followed the order of Xiushui 63 < Eryou 810 < Liangyoupeijiu < Zhenong 952. 相似文献
864.
Electro-coagulation was used to treat refectory wastewater with high oil and grease contents. Different operational conditions were examined, including pH, current density, reaction time, conductivity, electrode distance and inlet concentration. The optimum current density was 10-14 A m(-2) within 30 min depending on the wastewater properties tested. Conductivity had little effect on the treatment efficiency. Although the addition of extra salts (e.g., sodium chloride) to the wastewater did not help increase the pollutant removal efficiency, it could save the power consumption significantly. The COD(Cr) and oil removal efficiency descended with increasing electrode distance. The optimal electrode distance was determined to be 10 mm for this equipment in consideration of the treatment cost and efficiency together. The pH effect on the performance of the electro-coagulation process was not very significant in the range of 3-10. The removal efficiency of oil and COD(Cr) under normal condition exceeded 95% and 75%, respectively. 相似文献
865.
866.
867.
Sheth AC Sastry C Yeboah YD Xu Y Agarwal P 《Journal of the Air & Waste Management Association (1995)》2003,53(4):451-460
Catalyst recovery studies were conducted for gasified chars produced from steam gasification of Illinois #6 coal catalyzed with two different catalyst systems. A ternary (43.5 mol% Li2CO3-31.5 mol% Na2COr-25 mol% K2CO3) and a binary (29 mol% Na2CO3-71 mol% K2CO3) eutectic catalyst system were used for gasifying coal. Various extraction schemes, such as water extraction, H2SO4 extraction, and acetic acid extraction, were evaluated with respect to their extraction efficiencies. Effects of major process variables, such as solvent-to-char ratio, mixing time, temperature, and concentration, on the extraction efficiency were evaluated. A process schematic for the entire catalyst recovery, regeneration, and recycle scheme was developed and the preliminary process economics were determined based on these extraction schemes. H2SO4 extraction was found to be the most desirable. It also turned out to be more attractive than a once-through throwaway system. 相似文献
868.
869.
Plant uptake of aldicarb from contaminated soil and its enhanced degradation in the rhizosphere 总被引:3,自引:0,他引:3
Experiments were conducted to investigate the degradation of aldicarb, an oxime carbamate insecticide, in sterile, non-sterile and plant-grown soils, and the capability of different plant species to accumulate the pesticide. The degradation of aldicarb in soil followed first-order kinetics. Half lives (t1/2) of aldicarb in sterile and non-sterile soil were 12.0 and 2.7 days, respectively, which indicated that microorganisms played an important part in the degradation of aldicarb in soil. Aldicarb disappeared more quickly (p< or =0.05) in the soil with the presence of plants, and t1/2 of the pesticide were 1.6, 1.4 and 1.7 days in the soil grown with corn, mung bean and cowpea, respectively. Comparison of plant-promoted degradation and plant uptake showed that the enhanced removal of aldicarb in plant-grown soil was mainly due to plant-promoted degradation in the rhizosphere. 相似文献
870.