全文获取类型
收费全文 | 3824篇 |
免费 | 104篇 |
国内免费 | 1352篇 |
专业分类
安全科学 | 210篇 |
废物处理 | 217篇 |
环保管理 | 304篇 |
综合类 | 1875篇 |
基础理论 | 692篇 |
环境理论 | 1篇 |
污染及防治 | 1547篇 |
评价与监测 | 147篇 |
社会与环境 | 124篇 |
灾害及防治 | 163篇 |
出版年
2024年 | 1篇 |
2023年 | 63篇 |
2022年 | 184篇 |
2021年 | 126篇 |
2020年 | 95篇 |
2019年 | 88篇 |
2018年 | 146篇 |
2017年 | 161篇 |
2016年 | 164篇 |
2015年 | 209篇 |
2014年 | 301篇 |
2013年 | 365篇 |
2012年 | 328篇 |
2011年 | 306篇 |
2010年 | 234篇 |
2009年 | 273篇 |
2008年 | 270篇 |
2007年 | 222篇 |
2006年 | 209篇 |
2005年 | 150篇 |
2004年 | 114篇 |
2003年 | 144篇 |
2002年 | 128篇 |
2001年 | 109篇 |
2000年 | 120篇 |
1999年 | 130篇 |
1998年 | 142篇 |
1997年 | 84篇 |
1996年 | 78篇 |
1995年 | 76篇 |
1994年 | 60篇 |
1993年 | 56篇 |
1992年 | 48篇 |
1991年 | 15篇 |
1990年 | 20篇 |
1989年 | 11篇 |
1988年 | 12篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有5280条查询结果,搜索用时 156 毫秒
961.
962.
Black carbons(e.g.,charcoal) have a great impact on the transport of organic contaminants in soil and water because of its strong affnity and ubiquity in the environment.To further elucidate their interaction mechanism,sorption of polar(p-nitrotoluene,m-dinitrobenzene and nitrobenzene) and nonpolar(naphthalene) aromatic contaminants to burned straw ash charcoal under different de-ashed treatments were investigated.The sorption isotherms fitted well with Freundlich equation,and the Freundlich N values were all around 0.31-0.38,being independent of the sorbate properties and sorbent types.After sequential removal of ashes by acid treatments(HCl and HCl-HF) ,both adsorption and partition were enhanced due to the enrichment of charcoal component.The separated contribution of adsorption and partition to total sorption were quantified.The effective carbon content in ash charcoal functioned as adsorption sites,partition phases,and hybrid regions with adsorption and partition were conceptualized and calculated.The hybrid regions increased obviously after de-ashed treatment.The linear relationships of Freundlich N values with the charring-temperature of charcoal or biochar(the charred byproduct in biomass pyrolysis) were observed based on the current study and the cited publications which included 15 different temperatures(100-850°C) ,10 kinds of precursors of charcoal/biochar,and 10 organic sorbates. 相似文献
963.
Juan Huang Jun Xiao Yang Guo Wenzu Guan Chong Cao Chunni Yan Mingyu Wang 《环境科学学报(英文版)》2020,32(1):319-330
Silver nanoparticles(AgNPs) have been widely used in many fields,which raised concerns about potential threats to biological sewage treatment systems.In this study,the phosphorus removal performance,enzymatic activity and microbial population dynamics in constructed wetlands(CWs) were evaluated under a long-term exposure to Ag NPs(0,50,and 200 μg/L) for 450 days.Results have shown that Ag NPs inhibited the phosphorus removal efficiency in a short-term exposure,whereas caused no obviously negative effects from a long-term perspective.Moreover,in the coexisting CW system of Ag NPs and phosphorus,competition exhibited in the initial exposure phase,however,cooperation between them was observed in later phase.Enzymatic activity of acid-phosphatase at the moderate temperature(10–20°C) was visibly higher than that at the high temperature(20–30℃) and CWs with Ag NPs addition had no appreciable differences compared with the control.High-throughput sequencing results indicated that the microbial richness,diversity and composition of CWs were distinctly affected with the extension of exposure time at different Ag NPs levels.However,the phosphorus removal performance of CWs did not decline with the decrease of polyphosphate accumulating organisms(PAOs),which also confirmed that adsorption precipitation was the main way of phosphorus removal in CWs.The study suggested that Ag NPs and phosphorus could be removed synergistically in the coexistence system.This work has some reference for evaluating the influences of Ag NPs on the phosphorus removal and the interrelation between them in CWs. 相似文献
964.
In this study, greatly enhanced Mn(II) adsorption was achieved by as-synthesized diethylenetriaminepentaacetate acid intercalated Mg/Al layered double hydroxides(LDHsDTPA). The adsorption capacity of LDHs-DTPA was 83.5 mg/g, which is much higher than that of LDHs-EDTA(44.4 mg/g), LDHs-Oxalate(21.6 mg/g) and LDHs(28.8 mg/g). The adsorption data of aqueous Mn(II) using LDHs-DTPA could be well described by the pseudosecond order kinetics and Langmuir isotherm model. Thermodynamics study results also showed that the adsorption process of Mn(II) by LDHs-DTPA was exothermic as indicated by the negative ΔH value. Furthermore, based on the structural, morphological and thermostable features, as well as FT-IR and XPS characterizations of LDHs-DTPA and the pristine LDHs, the adsorption mechanism of Mn(II) was proposed. The carboxyl groups of DTPA were proposed to be the main binding sites for Mn(II), and the hydroxyl groups of LDHs also played a minor role in the adsorption process. Among the three common regeneration reagents, 0.1 mol/L Na_2CO_3 was the best for reusing LDHs-DTPA in Mn(II)adsorption. Besides, the Mn(II) adsorption performance could be hindered in the presence of typical inorganic ions, especially cations. Further specific modifications of LDHs-DTPA are suggested to get more selective adsorption of Mn(II) in practical applications. 相似文献
965.
某石油化工园区秋季VOCs污染特征及来源解析 总被引:2,自引:4,他引:2
利用快速连续在线自动监测系统对某典型石油化工园区2014年秋季(9、10、11月)大气中VOCs进行监测,并对其组成、光化学反应活性、时间变化特征和来源进行解析.结果表明:秋季大气中VOCs的混合体积分数明显高于国内外其他城市和工业地区,且烷烃是大气中VOCs的最主要成分.研究区秋季3个月份大气中VOCs的混合体积分数之间差异不显著,但各种烃类的日夜变化特征明显:烷烃、烯烃和芳香烃呈现"单峰单谷"变化趋势,乙炔的变化趋势呈"W"型.PMF受体模型解析结果表明主要来源于天然气交通及溶剂、炼油厂的泄漏或挥发等过程,其次为其他交通来源,沥青对于研究区VOCs来源也有一定的贡献.等效丙烯体积和最大臭氧生成潜势对VOCs的光化学反应活性计算结果表明,烯烃和烷烃分别是各自混合体积分数的最主要的贡献者. 相似文献
966.
于2012年4月沿大九湖湿地平均分布10个采样点,各采集0~10、10~20以及20~30 cm浅层土壤,采用GC-MS对大九湖湿地浅层土壤中USEPA 16种优控多环芳烃(PAHs)进行分析,对其分布、组成、来源进行了详细的讨论,并对高山湿地PAHs污染标志物进行了浅析.结果表明,研究区0~10、10~20、20~30cm浅层土壤中∑16PAHs含量分别为48.55~984.73、14.36~806.47、12.84~1191.53 ng·g-1,均值分别为302.94、142.98、208.68 ng·g-1;7种致癌单体多环芳烃含量范围分别为21.20~844.29、2.96~592.06、0.66~964.70 ng·g-1,均值分别为197.25、93.16、147.16 ng·g-1,分别占总PAHs的65.12%、65.13%、69.08%;泥炭区PAHs含量明显高于非泥炭区,且已达到重度污染程度;PAHs组成以4、5、6环为主;结合IcdP/(IcdP+BghiP)及Pyr/BaP比值分析,推测大九湖湿地浅层土壤中PAHs主要来源于化石燃料及木材的燃烧,近年来旅游车辆的进入对PAHs的贡献较大;对浅层土壤中各单体PAH与PAHs总含量进行回归分析表明、苯并(b)荧蒽、茚(1,2,3cd)并芘、苯并(a)蒽作为泥炭地PAHs标志性化合物,用来评价PAHs的污染程度. 相似文献
967.
968.
969.
This study aims to increase the inactivation efficiency of CO_2 against Escherichia coli under mild conditions to facilitate the application of pressurized CO_2 technology in water disinfection. Based on an aerating-cycling apparatus, three different treatment methods(continuous aeration, continuous reflux, and simultaneous aeration and reflux) were compared for the same temperature, pressure(0.3–0.7 MPa), initial concentration, and exposure time(25 min). The simultaneous aeration and reflux treatment(combined method) was shown to be the best method under optimum conditions, which were determined to be 0.7 MPa, room temperature, and an exposure time of 10 min. This treatment achieved 5.1-log reduction after 25 min of treatment at the pressure of 0.3 MPa and 5.73-log reduction after 10 min at 0.7 MPa. Log reductions of 4.4 and 5.0 occurred at the end of continuous aeration and continuous reflux treatments at 0.7 MPa, respectively.Scanning electron microscopy(SEM) images suggested that cells were ruptured after the simultaneous aeration and reflux treatment and the continuous reflux treatment. The increase of the solubilization rate of CO_2 due to intense hydraulic conditions led to a rapid inactivation effect. It was found that the reduction of intracellular p H caused by CO_2 led to a more lethal bactericidal effect. 相似文献
970.
发光细菌的生理特性及其在环境监测中的应用 总被引:34,自引:3,他引:34
就发光细菌的生理特性、发光细菌毒性试验在环境监测中的应用及该技术的新进展3个方面进行了较为全面的概述;评价了发光细菌毒性试验的特点,提出了该技术今后的发展方向;可以预见它将成为环境监测的重要手段。 相似文献