全文获取类型
收费全文 | 700篇 |
免费 | 19篇 |
国内免费 | 40篇 |
专业分类
安全科学 | 36篇 |
废物处理 | 5篇 |
环保管理 | 95篇 |
综合类 | 383篇 |
基础理论 | 77篇 |
污染及防治 | 104篇 |
评价与监测 | 40篇 |
社会与环境 | 10篇 |
灾害及防治 | 9篇 |
出版年
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 18篇 |
2020年 | 17篇 |
2019年 | 10篇 |
2018年 | 13篇 |
2017年 | 8篇 |
2016年 | 15篇 |
2015年 | 13篇 |
2014年 | 21篇 |
2013年 | 21篇 |
2012年 | 19篇 |
2011年 | 46篇 |
2010年 | 19篇 |
2009年 | 43篇 |
2008年 | 30篇 |
2007年 | 51篇 |
2006年 | 36篇 |
2005年 | 31篇 |
2004年 | 24篇 |
2003年 | 33篇 |
2002年 | 35篇 |
2001年 | 28篇 |
2000年 | 35篇 |
1999年 | 40篇 |
1998年 | 35篇 |
1997年 | 21篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 15篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
排序方式: 共有759条查询结果,搜索用时 640 毫秒
471.
生物膜系统的微生物特征和运行管理 总被引:14,自引:1,他引:14
废水的生物膜处理法,是废水好氧生物处理法中除活性污泥法之外的又一大类方法,亦称之为固着生长法,该文分析了生物膜系统中微生物的种群及其分布特征,详细探讨了生物膜系统运行过程中的一些问题及其防治方法,生物膜法与活性污泥法相比,具有运行管理较简易,方便剩余污泥量少等优点,在处理规模不大的场合颇受欢迎。 相似文献
472.
Incorporation of a carbon-based nutrient enhancement strategy for drinking water biofiltration is an attractive option, especially for source waters which contain recalcitrant organics. This study compared biofilters that were operated in parallel and individually enhanced with amino acids (including alanine, phenylalanine, and tryptophan), inulin, and sucrose to increase biomass concentration and promote biodegradation of dissolved organic carbon (DOC) in the source water, including disinfection by-product (DBP) precursors. Biomass activity was characterized by measuring adenosine tri-phosphate (ATP), dissolved oxygen (DO) consumption, and through the use of laccase and esterase enzyme assays. Performance was evaluated in terms of headloss, turbidity, pH, DOC, UV254, and DBP formation potential (DBP FP). The introduction of carbon-based nutrients significantly increased biomass activity, where ATP values peaked at 976?ng/g of filter media, 853?ng/g, and 513?ng/g for amino acids, inulin, and sucrose-spiked biofilters, respectively, while a non-spiked control only reached 104?ng/g. DO utilization by the enhanced biofilters was significantly higher than the control, with a strong correlation between ATP and DO uptake observed for all filters (R2?>?0.74). Laccase and esterase enzyme activities of enhanced biofilters were also elevated (p?> 0.05), suggesting greater biodegradation potential. Operational parameters such as headloss development and turbidity control were not impaired by carbon supplementation strategies or an increase in biomass concentration and activity. However, the enhancement strategy did not provide improvement in terms of source water carbon removal (DOC and UV254) or DBP FP when treated filters were compared to a control. 相似文献
473.
474.
475.
交通噪声的衍射作用对住宅小区的影响 总被引:4,自引:0,他引:4
交通噪声对住宅小区的影响分析,除考虑直达声和反射声的影响外,还应加入衍射声场的作用。该文建立了典型住宅区中噪声衰减的完整理论模型,计算分析了交通噪声对建筑群纵深的影响,并对无规则分布的建筑群中声衰减作了定性分析。还以典型建筑群为例,对已知建筑布局下噪声在其中的衰减特征,作了说明和验证。 相似文献
476.
环境激素污染研究进展 总被引:20,自引:0,他引:20
环境激素污染,使生物与人类的持续生存和繁衍受到威胁,有关环境激素的研究在整体上尚属起步阶段。该文通过以下3方向:环境激素物质快速筛选的方法研究;环境激素对生物与人体的毒理影响研究;环境激素的表生行为和环境效应研究;综述了国内外有关环境激素的研究及进展。有机污染在我国相当严重,已发现许多有机物具雌激素作用,故开展环境激素污染的研究势在必行。 相似文献
477.
478.
479.
Simone L. Stevenson Kate Watermeyer Giovanni Caggiano Elizabeth A. Fulton Simon Ferrier Emily Nicholson 《Conservation biology》2021,35(2):522-532
At the global scale, biodiversity indicators are typically used to monitor general trends, but are rarely implemented with specific purpose or linked directly to decision making. Some indicators are better suited to predicting future change, others are more appropriate for evaluating past actions, but this is seldom made explicit. We developed a conceptual model for assigning biodiversity indicators to appropriate functions based on a common approach used in economics. Using the model, indicators can be classified as leading (indicators that change before the subject of interest, informing preventative actions), coincident (indicators that measure the subject of interest), or lagging (indicators that change after the subject of interest has changed and thus can be used to evaluate past actions). We classified indicators based on ecological theory on biodiversity response times and management objectives in 2 case studies: global species extinction and marine ecosystem collapse. For global species extinctions, indicators of abundance (e.g., the Living Planet Index or biodiversity intactness index) were most likely to respond first, as leading indicators that inform preventative action, while extinction indicators were expected to respond slowly, acting as lagging indicators flagging the need for evaluation. For marine ecosystem collapse, indicators of direct responses to fishing were expected to be leading, while those measuring ecosystem collapse could be lagging. Classification defines an active role for indicators within the policy cycle, creates an explicit link to preventative decision-making, and supports preventative action. 相似文献
480.
Yufei Shi Jinju Geng Xiang Li Yuli Qian Hongzhou Li Liye Wang Gang Wu Qingmiao Yu Ke Xu Hongqiang Ren 《环境科学学报(英文版)》2022,34(6):220-228
The characteristics of dissolved organic matter (DOM) can significantly affect the degradation of target compounds by the advanced oxidation processes. In this study, the effects of the different hydrophobicity/hydrophilicity fractions, molecular weight (MW) fractions, fluorescence components and molecular components of DOM extracted from municipal wastewater on the degradation of 4 pharmaceutically active compounds (PhACs), including carbamazepine, clofibric acid, atenolol and erythromycin by the UV/H2O2 process were investigated. The results showed that the degradation rate constants of 4 PhACs decreased dramatically in the presence of DOM. The linear regressions of 4 PhACs degradation as a function of specific fluorescence intensity (SFI) are exhibited during the degradation of 4 PhACs and the SFI may be used to evaluate effect of DOM on target compounds in wastewater. The hydrophobic acid (HPO-A) exhibited the strongest inhibitory effect on degradation of 4 PhACs during oxidation process. The small MW fractions of DOM significantly inhibited the degradation of 4 PhACs during oxidation process. Among three fluorescence components, hydrophobic humic-like substances may significantly inhibit the degradation of 4 PhACs during oxidation process. At the molecular level, the formulas may be derived from terrestrial sources. CHO compound may significantly inhibit the degradation of 4 PhACs during oxidation process on formula classes. The unsaturated hydrocarbons, carbohydrates and tannins compounds may significantly inhibit the effectiveness of the UV/H2O2 process on compound classes. 相似文献