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991.
含油污泥调质影响因素研究 总被引:2,自引:0,他引:2
针对某炼油污水处理厂产生的含油污泥,采用调质-机械分离方法进行处理。考察温度、pH值和搅拌时间对含油污泥调质效果的影响。结果表明,以PR—A复合药剂为调质剂,在温度为70℃-80℃,pH值为4.0—5.0,搅拌时间为30min条件下,经55kPa(绝压)抽滤后,含油污泥的处理效果最好,滤饼含水率可达到70.3%,进一步方便含油污泥的后续处理,有利于污泥的资源化利用和无害化处理。 相似文献
992.
993.
994.
Jan Šíma Marek Kobera Martin Šeda Lukáš Rokos Jan Vondruška Jiří Krejsa 《Journal of environmental science and health. Part. B》2020,55(4):319-328
AbstractThe content of Al, As, Be, Cd, Ca, Cr, Co, Cu, Fe, Pb, Li, Mg, Mn, Ni, Rb, Se, Sr, and Zn in fruiting bodies of edible mushrooms Calocybe gambosa, Entoloma clypeatum, Entoloma saepium, Xerocomellus chrysenteron, and Amanita rubescens growing in an orchard planted with fruit trees and situated close to a high-grown forest was studied during years 2016–2018. A. rubescens showed the highest potential of the element accumulation with bioconcentration factors of 48.5, 16.2, 7.80, 6.53, 1.75, and 1.68 obtained for Rb, Cd, Cu, Zn, Sr, and Mg, respectively. Both Entoloma species accumulated the elements similarly with bioconcentration factors >1.0 obtained for Rb, Cu, Cd, and Mg. Bioconcentration factors <0.05 were obtained for Al, Cr, Fe, and Pb in all studied species. The contents of beryllium (<0.1?mg/kg dry matter) were always the lowest among the studied elements. The contents of some elements of studied mushroom species significantly fluctuated over the years. Despite the fact that some studied elements (As, Be, Cd, Pb, Ni) are considerably toxic for humans, the pronounced effect on health is not expected if the studied mushroom species are consumed occasionally and do not represent the main component of the diet. 相似文献
995.
土壤污染物修复目标值的制定是污染场地环境管理的重要环节,制定科学合理的修复目标值是能否实现绿色可持续修复的关键。通过对比分析美国、英国、加拿大、澳大利亚等国家修复目标值的内涵、制定技术方法和决策管理机制,发现国内外关于土壤污染物修复的总体目标基本一致,即以保护人体健康和生态环境质量作为总体控制要求;但对于具体场地的定量修复目标值,国内外在制定依据、制定方法、决策管理机制等方面存在差异。我国主要在健康风险评估阶段,采用第一和第二层次风险评估方法确定修复目标值,而欧美国家主要基于全过程风险管理的决策管理机制,结合土壤中污染物的形态归趋和迁移转化规律,采用不同层次的风险评估,制定地块特征的修复目标值,保证健康风险和环境风险均达到可接受水平。借鉴国外经验,结合我国污染地块环境管理实践,提出土壤污染物修复目标值制定方法优化的建议:1) 统筹考虑人体健康风险和环境风险;2) 建立基于层次化、精细化的风险评估与修复目标值确定方法体系;3) 构建修复目标值动态适应性调整机制;4) 形成污染地块全过程风险管理机制。 相似文献
996.
997.
Jochen Harnisch Reinhard Borchers Peter Fabian 《Environmental science and pollution research international》1995,2(4):229-232
Measurements of carbonyl sulfide (COS) and carbondisulfide (CS2) were carried out on samples drawn from a smoke stack of an aluminium smelter. Volume mixing ratios of 6 ppm COS and 0.1
ppm CS2 were measured for gases from the electrolysis unit that had previously passed an Al2O3 fluid bed reactor and electrostatic precipitators. Specific emissions of 1.6 kg COS and 0.03 kg CS2 per ton of primary aluminium were found. Extrapolating from this particular smelter’s conditions to a world mix specific
COS emissions of about 4 kg/t(Al) are calculated resulting in emissions of annually 0.08 Tg COS into the atmosphere due to
electrolytic aluminium production in 1995. Besides the photochemical conversion of anthropogenic CS2 aluminium production is established to be the second major industrial source of COS probably exceeding automotive tire wear’s
and coal combustion’s contributions. 相似文献
998.
金属离子螯合剂氨三乙酸(nitrilotriacetic acid, NTA)可提高微量金属离子的生物可用性,促进厌氧消化产甲烷。借助气相色谱分析,在探讨系统酸性pH值对厌氧消化甲烷产量影响的基础上,重点研究了初始pH值对NTA促进产甲烷效果的影响。结果表明,系统初始pH值对厌氧消化产甲烷有一定的影响,其影响程度与溶液中游离乙酸的浓度密切相关。NTA对产甲烷的促进作用在pH值为6.5和7.0时较为明显,而在更低pH条件下,几乎没有促进作用。当pH为7.0、添加10 μmol/L NTA时,与对照样相比,累积甲烷产量增加了38.5%,而pH 6.0时,作用却不明显。 相似文献
999.
1000.
Derivation of predicted no effect concentrations (PNEC) for 2,4,6-trichlorophenol based on Chinese resident species 总被引:4,自引:0,他引:4
2,4,6-Trichlorophenol (2,4,6-TCP) is a common chemical intermediate and a by-product of water chlorination and combustion processes, and is a priority pollutant of the aquatic environment in many countries. Although information on the toxicity of 2,4,6-TCP is available, there is a lack of information on the predicted no-effect concentration (PNEC) of 2,4,6-TCP, mainly due to the shortage of chronic and site-specific toxicity data. In the present study, acute and sub-chronic toxicity of 2,4,6-TCP on six different resident Chinese aquatic species were determined. PNEC values were calculated and compared by use of two approaches: assessment factor (AF) and species sensitivity distribution (SSD). Values for acute toxicity ranged from 1.1 mg L−1 (Plagiognathops microlepis) to 42 mg L−1 (Corbicula fluminea) and the sub-chronic no observed effect concentrations (NOECs) ranged from 0.05 mg L−1 (Mylopharyngodon piceus) to 2.0 mg L−1 (C. fluminea). PNECs obtained by the assessment factor approach with acute (AF = 1000, 0.001 mg L−1) or chronic (AF = 10, 0.005 mg L−1) toxicity data were one order of magnitude less than those from SSD methods (0.057 mg L−1). PNEC values calculated using SSD methods with a 50% certainty for 2,4,6-TCP was less than those obtained by use of the USEPA recommend final chronic value (FCV) method (0.097 mg L−1) and the one obtained by use of the USEPA recommend acute-to-chronic (ACR) methods (0.073 mg L−1). PNECs derived using AF methods were more protective and conservative than that derived using SSD methods. 相似文献