全文获取类型
收费全文 | 3677篇 |
免费 | 476篇 |
国内免费 | 1433篇 |
专业分类
安全科学 | 529篇 |
废物处理 | 160篇 |
环保管理 | 348篇 |
综合类 | 2694篇 |
基础理论 | 561篇 |
污染及防治 | 696篇 |
评价与监测 | 212篇 |
社会与环境 | 219篇 |
灾害及防治 | 167篇 |
出版年
2024年 | 21篇 |
2023年 | 100篇 |
2022年 | 251篇 |
2021年 | 245篇 |
2020年 | 276篇 |
2019年 | 194篇 |
2018年 | 206篇 |
2017年 | 256篇 |
2016年 | 206篇 |
2015年 | 295篇 |
2014年 | 329篇 |
2013年 | 368篇 |
2012年 | 401篇 |
2011年 | 385篇 |
2010年 | 342篇 |
2009年 | 289篇 |
2008年 | 309篇 |
2007年 | 266篇 |
2006年 | 212篇 |
2005年 | 126篇 |
2004年 | 89篇 |
2003年 | 53篇 |
2002年 | 63篇 |
2001年 | 60篇 |
2000年 | 35篇 |
1999年 | 35篇 |
1998年 | 33篇 |
1997年 | 31篇 |
1996年 | 17篇 |
1995年 | 24篇 |
1994年 | 19篇 |
1993年 | 18篇 |
1992年 | 15篇 |
1991年 | 4篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有5586条查询结果,搜索用时 156 毫秒
991.
对工业污水排放的有效监管是水环境保护的重要环节。分析了我国目前监管主体所处的困境,考虑中央监察与公众参与的监督约束作用,构建了水环境监管体系。并设计出具有激励约束惩罚效力的水环境监管契约,建立委托 代理模型,通过求解得出监管契约中污水排放标准、监管频率、补偿额度以及罚款数额的最优值。在此基础上,以太湖流域两个成本类型差异较大的印染企业为例,定量设计两级水环境监管契约,分析公众参与程度和地方政府庇护企业程度对契约取值的影响。结果表明:提高公众参与程度可以有效降低罚款额度,削减政企矛盾;当公众参与程度和惩罚额度一定时,通过环境问责等制度降低地方政府庇护企业的程度,能够减小监管频率,从而削减监管执行成本 相似文献
992.
This article describes the photolysis of azithromycin, a macrolide antibiotic with reported occurrence in environmental waters, under simulated solar radiation. The photodegradation followed first-order reaction kinetics in five matrices examined. In HPLC water, the degradation rate was the slowest (half-life: 20 h), whereas in artificial freshwater supplemented with nitrate (5 mg L−1) or humic acids (0.5 mg L−1) the degradation of azithromycin was enhanced by factors of 5 and 16, respectively, which indicated the role of indirect photolysis involving the formation of highly reactive species. Following chromatographic separation on a UPLC system, the characterization of the transformation products was accomplished using high-resolution QqToF-MS analysis. The presence of seven photoproducts was observed and their formation was postulated to originate from (bis)-N-demethylation in the desosamine sugar, O-demethylation in the cladinose sugar, combinations thereof, as well as from hydrolytic cleavages of the desosamine and/or cladinose residue. Two of these photoproducts could also be detected in natural photodegradation process in river water which was spiked with azithromycin. 相似文献
993.
994.
改性硅藻土用于巢湖水脱磷研究 总被引:5,自引:1,他引:4
采用改性硅藻土强化混凝处理巢湖水,以达到除磷的目的.研究了改性硅藻土除磷最适操作条件,并将改性硅藻土同几种常规混凝剂的处理效果和其经济性进行了对比.结果表明:改性硅藻土和水的混合搅拌速度梯度为260 s-1左右,絮凝反应速度梯度为20 s-1左右,絮凝时间15 min,沉淀时间1 h,改性硅藻土投加量50~100 mg... 相似文献
995.
996.
997.
Sorption of pyrene on black carbons (BCs) obtained by heating sawdust at two temperatures (400 and 700 °C, denoted as 400BC and 700BC, respectively), as well as on modified BCs (via oxidation, oximation, and hydrolysis) was studied to investigate the role of BC structural characteristics in sorption of hydrophobic organic compounds. Pyrene was bound strongly by 700BC and 400BC, with organic carbon normalized distribution coefficients (Koc) of 105.04-105.86 and 104.65-105.16, respectively, at equilibrium pyrene concentrations of 10-100 μg L−1. Both chemical composition and pore distribution of the two BCs changed after modifications, which led to changes in their sorption characteristics for pyrene. After modifications, the linearity of pyrene sorption isotherm increased for 700BC but decreased for 400BC. For 700BC, both oxidation and oximation reduced pyrene sorption, with Koc decreasing by 69.1-73.7% and 18.7-33.9%, respectively, whereas hydrolysis did not exert a significant influence. For 400BC, oxidation and hydrolysis reduced Koc by 2.28-25.9% and 29.2-33.9%, respectively, while oximation increased Koc. In most cases, the change in sorption capacity could be explained by the changes in C content and type, polarity, surface area, and micropore volume of the BCs; however, the role of conformation (the accessibility to sorption sites) could not be ignored. 相似文献
998.
Contaminants in the coastal karst aquifer system along the Caribbean coast of the Yucatan Peninsula, Mexico 总被引:1,自引:0,他引:1
Metcalfe CD Beddows PA Bouchot GG Metcalfe TL Li H Van Lavieren H 《Environmental pollution (Barking, Essex : 1987)》2011,159(4):991-997
Intensive land development as a result of the rapidly growing tourism industry in the “Riviera Maya” region of the Yucatan Peninsula, Mexico may result in contamination of groundwater resources that eventually discharge into Caribbean coastal ecosystems. We deployed two types of passive sampling devices into groundwater flowing through cave systems below two communities to evaluate concentrations of contaminants and to indicate the possible sources. Pharmaceuticals and personal care products accumulated in the samplers could only have originated from domestic sewage. PAHs indicated contamination by runoff from highways and other impermeable surfaces and chlorophenoxy herbicides accumulated in samplers deployed near a golf course indicated that pesticide applications to turf are a source of contamination. Prevention and mitigation measures are needed to ensure that expanding development does not impact the marine environment and human health, thus damaging the tourism-based economy of the region. 相似文献
999.
Shi W Wang X Hu G Hao Y Zhang X Liu H Wei S Wang X Yu H 《Environmental pollution (Barking, Essex : 1987)》2011,159(2):441-448
Thyroid hormone (TH) agonist and antagonist activities of water sources along the Yangtze River in China were surveyed by a green monkey kidney fibroblast (CV-1) cell-based TH reporter gene assay. Instrumental analysis was conducted to identify the responsible thyroid-active compounds. Instrumentally derived l-3,5,3′-triiodothyronine (T3) equivalents (T3-EQs) and thyroid receptor (TR) antagonist activity equivalents referring to dibutyl phthalate (DBP-EQs) were calculated from the concentrations of individual congeners. The reporter gene assay demonstrated that three out of eleven water sources contained TR agonist activity equivalents (TR-EQs), ranging from 286 to 293 ng T3/L. Anti-thyroid hormone activities were found in all water sources with the TR antagonist activity equivalents referring to DBP (Ant-TR-EQs), ranging from 51.5 to 555.3 μg/L. Comparisons of the equivalents from instrumental and biological assays suggested that high concentrations of DBP and di-2-ethylhexyl phthalate (DEHP) were responsible for the observed TR antagonist activities at some locations along the Yangtze River. 相似文献
1000.
伴随着建筑废弃物产生量的迅速增长,建筑废弃物循环利用已成为循环经济发展的重点领域。从完善的法律法规、深度循环利用方式和产业化发展等方面,对国外发达国家废弃物循环利用的经验和做法加以总结和提升,并结合我国实际,提出建立健全我国建筑废弃物法律法规体系、构筑多级循环利用模式和培育废弃物利用产业体系的几点启示,以期为我国相关部门制定建筑废弃物的相关政策制度、提高建筑废弃物的循环再利用水平提供参考和依据。 相似文献