全文获取类型
收费全文 | 4242篇 |
免费 | 589篇 |
国内免费 | 2814篇 |
专业分类
安全科学 | 343篇 |
废物处理 | 224篇 |
环保管理 | 340篇 |
综合类 | 4131篇 |
基础理论 | 952篇 |
环境理论 | 1篇 |
污染及防治 | 1291篇 |
评价与监测 | 243篇 |
社会与环境 | 101篇 |
灾害及防治 | 19篇 |
出版年
2024年 | 15篇 |
2023年 | 117篇 |
2022年 | 181篇 |
2021年 | 239篇 |
2020年 | 180篇 |
2019年 | 236篇 |
2018年 | 278篇 |
2017年 | 286篇 |
2016年 | 355篇 |
2015年 | 343篇 |
2014年 | 362篇 |
2013年 | 411篇 |
2012年 | 503篇 |
2011年 | 489篇 |
2010年 | 391篇 |
2009年 | 478篇 |
2008年 | 309篇 |
2007年 | 353篇 |
2006年 | 381篇 |
2005年 | 279篇 |
2004年 | 210篇 |
2003年 | 219篇 |
2002年 | 180篇 |
2001年 | 153篇 |
2000年 | 138篇 |
1999年 | 112篇 |
1998年 | 83篇 |
1997年 | 73篇 |
1996年 | 68篇 |
1995年 | 64篇 |
1994年 | 36篇 |
1993年 | 35篇 |
1992年 | 28篇 |
1991年 | 21篇 |
1990年 | 12篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有7645条查询结果,搜索用时 15 毫秒
991.
Trotta F Cravotto G Casile G 《Environmental science and pollution research international》2003,10(3):144-146
Chiral, atropisomeric 2,2'-dihydroxy-1,1'-binaphthyl has been extensively used to direct asymmetric processes. Its key role in asymmetric catalysis has spurred efforts to synthesize it in the optically pure form, but the reported synthetic routes have a significant environmental impact. In an aqueous peroxydase-cyclodextrin system the oxidative coupling of 2-naphthol took place very rapidly in almost quantitative yield and resulted in an enantiomeric excess. This one-pot synthesis do not require any organic solvents and oxidising metal cations. 相似文献
992.
993.
994.
The toxicity of seawater dispersions of a chemical dispersant to two marine crustaceans was investigated in the presence and absence of various quantities of a non-toxic mineral oil. From the results and a physical-chemical partitioning analysis, a limiting value of the oil-water partition coefficient of the toxic compounds is deduced suggesting that essentially all of the toxic compounds in the dispersant will partition into solution in water following dispersant application to an oil spill. This conclusion simplifies interpretation and prediction of the toxic effects of a dispersed oil spill.The combined bioassay-partitioning procedure may have applications to the study of the toxicity of other complex mixtures such as industrial effluents. 相似文献
995.
Domènech X Ayllón JA Peral J 《Environmental science and pollution research international》2001,8(4):285-287
The paper focuses on the production of H2O2 by photocatalysis over ZnO in an aerated aqueous phase. The presence of different reductants that increase the H2O2 production in the aqueous phase is analysed; particular attention is paid to nitrite, which has been shown to be the reductant that produces the most significant increments in the H2O2 production. The photocatalytic anodic decomposition of ZnO in the presence of the different reductants is also investigated. From the results obtained, the relevance of the ZnO photocatalysis in the formation of environmental hydrogen peroxide is estimated. 相似文献
996.
The fluorescence spectroscopic behavior of bromadiolone (anticoagulant rodenticide), a substituted 4-hydroxycoumarin derivative, was investigated in water and in organized media like micelles and cyclodextrins. A detailed study on various photophysical parameters like fluorescence intensity (IF), quantum yield (), lifetime (τ) and steady state fluorescence anisotropy (r) of bromadiolone in aqueous and in organized media was carried out. Bromadiolone in aqueous solution was observed to be in an aggregated state, thereby showing weak emission due to self-quenching. Marked enhancement of fluorescence intensity was observed in organized media like micelles and β-cyclodextrin. A preliminary investigation has been done to find out whether this enhancement of fluorescence can be used to develop a sensitive analytical method for determination of bromadialone in aqueous media. A linear relationship between the fluorescence intensity and concentration of bromadiolone was observed in the range of 0.15–7.9 μg ml−1 in cetyltrimethylammonium bromide (CTAB) and 0.5–26.4 μg ml−1 in β-cyclodextrin medium. The lower detection limit was found to be 37 ng ml−1 in presence of CTAB and 23 ng ml−1 in β-cyclodextrin. Comparison with 4-hydroxycoumarin, an unsubstituted analogue, was made. 相似文献
997.
通过化学合成法制备了磁性核壳CoFe2O4@SiO2@PIL-AO复合材料,采用傅立叶变换红外光谱(FTIR)、扫描电镜(SEM)和X射线光电子能谱(XPS)对其进行了表征,研究了溶液pH、吸附时间、U (VI)初始浓度和温度等参数对U (VI)吸附性能的影响.实验结果表明:在c0=0.2 mg·L-1、pH=6.00±0.05、T=298.15 K、m=0.02 g和t=8 h的条件下,CoFe2O4@SiO2@PIL-AO对U (VI)的吸附作用最强,吸附率达到了97.54%;CoFe2O4@SiO2@PIL-AO吸附U (VI)是一个自发进行的吸热反应,U (VI)吸附动力学符合准二级动力学模型,吸附等温线符合Freundlich模型;CoFe2O4@SiO2@PIL-AO复合材料具有良好的可循环使用性,循环使用5次后它对U (VI)的吸附容量没有明显下降,可重复使用. 相似文献
998.
为了降低准好氧矿化垃圾床渗滤液尾水中有机物浓度和提高体系可生化性,构建了GAC(粒状活性炭)-O_3/H_2O_2体系催化降解矿化垃圾床渗滤液尾水中有机物.同时,考察了体系O_3、GAC和H_2O_2投加量、初始pH值对GAC-O_3/H_2O_2体系处理渗滤液尾水的影响,并使用分子量分布、紫外-可见光谱和三维荧光光谱解析了难降解有机物在GAC-O_3/H_2O_2体系的转化机制.结果表明:在GAC投加量为10 g·L-1,O_3投加量为32.16 mg·min-1,H_2O_2投加量为3 m L·L-1,初始pH值为5的条件下,反应20 min后,其渗滤液尾水的COD和UV245分别从700.08 mg·L~(-1)和0.488下降到393.85 mg·L~(-1)和0.244,COD和UV254的去除率分别为43.80%和50.00%.经GAC-O_3/H_2O_2体系处理后,得益于含芳香环有机物的有效降解,渗滤液尾水中大分子有机物(大于50 k Da)明显减少,分子量小于1 k Da的有机物比例增多.与此同时,紫外区类富里酸荧光区及可见光区类富里酸荧光区峰值也大幅降低,其去除率分别为70.20%和58.69%,B/C从0.04增加到0.35,这也使得废水可生化性大幅提高. 相似文献
999.
1000.
PCR-DGGE技术分析倒置A~2/O工艺处理染织废水中的微生物区系 总被引:3,自引:1,他引:2
基于16S rDNA的PCR-DGGE(polymerase chain reaction-denaturing gradient gel electrophoresis)技术研究了倒置A2/O(anoxic-anaerobic-aerobic)工艺处理染织废水过程中的微生物群落结构.从兼氧、厌氧和好氧区共取6个不同处理阶段的样品,测量了不同处理阶段样品的COD、pH、NH4+-N、H2S、总磷(TP)、污泥含量(TS)、色度及其脱除率,并分析了这些指标的变化规律.结果显示,COD在处理后期降到了145mg·L-1,NH4+-N的脱除率可达到85%,硫化氢的去除率达到了90%以上,磷的脱除率可达80%以上,TS处于逐渐升高的趋势,色度的脱除率达到65%.DGGE图谱显示,好氧处理阶段的微生物多样性明显比兼氧处理和厌氧处理的阶段的要丰富. 相似文献