全文获取类型
收费全文 | 9775篇 |
免费 | 362篇 |
国内免费 | 3794篇 |
专业分类
安全科学 | 734篇 |
废物处理 | 644篇 |
环保管理 | 859篇 |
综合类 | 5070篇 |
基础理论 | 1644篇 |
环境理论 | 2篇 |
污染及防治 | 3871篇 |
评价与监测 | 392篇 |
社会与环境 | 319篇 |
灾害及防治 | 396篇 |
出版年
2024年 | 5篇 |
2023年 | 151篇 |
2022年 | 482篇 |
2021年 | 390篇 |
2020年 | 282篇 |
2019年 | 264篇 |
2018年 | 354篇 |
2017年 | 456篇 |
2016年 | 520篇 |
2015年 | 666篇 |
2014年 | 807篇 |
2013年 | 1046篇 |
2012年 | 901篇 |
2011年 | 889篇 |
2010年 | 687篇 |
2009年 | 655篇 |
2008年 | 733篇 |
2007年 | 584篇 |
2006年 | 495篇 |
2005年 | 367篇 |
2004年 | 287篇 |
2003年 | 352篇 |
2002年 | 304篇 |
2001年 | 252篇 |
2000年 | 260篇 |
1999年 | 244篇 |
1998年 | 248篇 |
1997年 | 242篇 |
1996年 | 222篇 |
1995年 | 173篇 |
1994年 | 118篇 |
1993年 | 122篇 |
1992年 | 104篇 |
1991年 | 79篇 |
1990年 | 54篇 |
1989年 | 26篇 |
1988年 | 27篇 |
1987年 | 10篇 |
1986年 | 17篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
321.
UV-catalytic treatment of spent caustic from ethene plant with hydrogen peroxide and ozone oxidation 总被引:1,自引:0,他引:1
YU Zheng-zhe SUN De-zhi LI Chang-hai SHI Peng-fei DUAN Xiao-dong SUN Guo-rong LIU Jun-xin 《环境科学学报(英文版)》2004,16(2):270-275
The performance of UV/H2O2, UV/O3 and UV/H2O2/O3 oxidation systems for treating spent caustic from an ethylene plant was investigated, in UV/H2O2 system, with the increase of H202 dosage, removal efficiencies of COD and the ratio of biochemical oxygen demand(BOD) to chemical oxygen demand(COD) of the effluent were increased and a better performance was obtained than the H2O2 system alone. In UV/H2O2 system, removal efficiency of COD reach 68% under the optimum condition, and BOD/COD ratio was significantly increased from 0.22 to 0.52. In UV/O3 system, with the increase of O3 dosage, removal efficiency of COD and BOD/COD ratio were increased, and a better performance was obtained than the O3 system alone. Under the optimum condition, removal efficiency of COD was 54%, and BOD/COD ratio was significantly increased from 0.22 to 0.48. In UV/H2O2/O3 system, COD removal efficiency was found to be 22.0% higher than UV/O3 system. 相似文献
322.
Effect of nitrogen and phosphorus on the water quality in the Three Gorges Reservoir Area during and after its construction 总被引:5,自引:1,他引:5
A survey concerning the concentration of the nutrients in the Three Gorges Reservoir Area was carried out. This paper presents the parameters(NO3^- -N, NO2^- -N, KjeldahI-N, non-ionic ammonia, P-PO4 and TP)determined at 16 sampling sites from 1997 to 1999. The dominant soluble nitrogen form was NO3^- -N followed by KjeldahI-N, NO2^- -N and non-ionic ammonia. Mean values of NO3^- -N, NO2^- -N, Kjeldahl-N and non-ionic ammonia ranged from 0.50 to 2.37 mg/L, 0.022 to 0.084 mg/L, 0.33 to 0.99 mg/L and 0.007 to 0.092 mg/L respectively.Mean values of P-PO4 at most sampling sites were higher than 0.1 mg/L for subject to eutrophication. The major factors influencing the concentrations of N and P might be agricultural runoff, municipal and industrial effluents. In addition, 6 kinds of soil were sampled at the area where would inundated after the dam completed. Two approaches were adopted to simulate the N and P release from the inundated soils. The results showed that the soils would release nitrogen and phosphorus to the overlying water when the soils were inundated. The characteristics of soil affected the equilibrium concentrations of N and P between the soil and the overlying water. 相似文献
323.
IntroductionThesorptionofhydrophobicorganiccontaminants(HOCs)onnaturalgeosorbentsplaysasignificantroleintheirtransport,degradationandultimatefateintheaquaticenvironment (Alexander,1995 ;Luthy ,1997;Weber,2 0 0 1) .Sincethelate 1970s,theorganicmatter(OM)ha… 相似文献
324.
Investigation on Cr( Ⅵ ) reduction was conducted using Pseudomonas aeruginosa. The study demonstrated that the Cr(Ⅵ) canbe effectively reduced to Cr( Ⅲ ) by Pseudomonas aeruginosa. The effects of the factors affecting Cr( Ⅵ ) reduction rate including carbon source type, pH, initial Cr(Ⅵ) concentration and amount of calls inoculum were thoroughly studied. Malate was found to yield maximum biotransformation, followed by succinate and glucose, with the reduction rate of 60.86%, 43. 76% and 28.86% respectively. The optimum pH for Cr( Ⅵ ) reduction was ?.0, with reduction efficiency of 61.71 % being achieved. With the increase of initial Cr(Ⅵ) concentration,the rate of Cr(Ⅵ) reduction decreased. The reduction was inhibited strongly when the initial Cr(Ⅵ) concentration increased to 157 mg/L. As the amount of cells inoculum increased, the rate of Cr( Ⅵ ) reduction also increased. The mechanism of Cr( Ⅵ ) reduction and final products were also analysed. The results suggested that the soluble enzymes appear to be responsible for Cr (Ⅵ) reduction by Pseudomonas aeruginosa, and the reduced Cr( Ⅲ ) was not precipitated in the form of Cr(OH)3. 相似文献
325.
Sensitized effect of β-cyclodextrin on the fluorescence in the determination of carbaryl 总被引:1,自引:0,他引:1
Based on the significant enhancement of fluorescence intensity of carbaryl in inclusion complex, a spetrofluorimetdc method with high sensitivity was developed for the determination of carbaryl in aqueous solution. Under the optimum conditions, the complex had excitation and emission maxima at 278 nm and 332 nm, respectively. The linear range of the method was 7.0 ng/ml-1500 ng/ml with a detection limit of 1.2 ng/ml. The proposed method was successfully used to determine quantitativelv of carbarvl in cottonseeds. 相似文献
326.
IntroductionWiththedevelopmentandapplicationofnewpesticide ,insecticidehasgreatlyreducedtheharmofpesttocrops .Bifenthrinisaneffectivepyrethroidinsecticideandacaricideagainstawiderangeofinsectpests ,anditisverypoisonoustomammal,aquatic .Thisinsecticideiswi… 相似文献
327.
The utility of nickel/iron in the remediation of atraz.ine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atraz.ine under acidic conditions. The dechlonnation reaction approximately followed the first-order kinetics under the experimental conditions( nickel/iron: 1.0 g/250 ml: Ca~r~ = 20.0 mg/L), the reaction rate increased with decreasing pH value of the reaction solution and increasing the proportion of Ni: Fe within 2.95 %. For condition with 2.95% nickel/iron, the reaction rate constants were 0.07518( R = 0.9927), 0.06212( R = 0.9846) and 0.00131 min^-1 ( R = 0.9.565) at pH = 2.0, 3.0 and 4.0, respectively. HPLC analysis was used to monitor the decline of atraz.ine concentration. 相似文献
328.
Yuanhang Zhang Yuesi Wang Xin Jin Zirui Liu Gehui Wang Guiqian Tang Keding Lu Bo Hu Shanshan Wang Guohui Li Xinqin An Chao Wang Qihou Hu Lingyan He Fenfen Zhang 《环境科学学报(英文版)》2023,123(1):350-366
Atmospheric oxidizing capacity (AOC) is an essential driving force of troposphere chemistry and self-cleaning, but the definition of AOC and its quantitative representation remain uncertain. Driven by national demand for air pollution control in recent years, Chinese scholars have carried out studies on theories of atmospheric chemistry and have made considerable progress in AOC research. This paper will give a brief review of these developments. First, AOC indexes were established that represent apparent atmospheric oxidizing ability (AOIe) and potential atmospheric oxidizing ability (AOIp) based on aspects of macrothermodynamics and microdynamics, respectively. A closed study refined the quantitative contributions of heterogeneous chemistry to AOC in Beijing, and these AOC methods were further applied in Beijing-Tianjin-Hebei and key areas across the country. In addition, the detection of ground or vertical profiles for atmospheric OH·, HO2·, NO3· radicals and reservoir molecules can now be obtained with domestic instruments in diverse environments. Moreover, laboratory smoke chamber simulations revealed heterogeneous processes involving reactions of O3 and NO2, which are typical oxidants in the surface/interface atmosphere, and the evolutionary and budgetary implications of atmospheric oxidants reacting under multispecies, multiphase and multi-interface conditions were obtained. Finally, based on the GRAPES-CUACE adjoint model improved by Chinese scholars, simulations of key substances affecting atmospheric oxidation and secondary organic and inorganic aerosol formation have been optimized. Normalized numerical simulations of AOIe and AOIp were performed, and regional coordination of AOC was adjusted. An optimized plan for controlling O3 and PM2.5 was analyzed by scenario simulation. 相似文献
329.
Yuanhang Zhang Yanhui Liu Jiayin Li Yufang M Ming Zhou Zhaofeng Tan Limin Zeng Keding Lu 《环境科学学报(英文版)》2023,123(1):522-534
The atmospheric chemical mechanism is an essential component of airshed models used for investigating the chemical behaviors and impacts of species. Since the first tropospheric chemical mechanism was proposed in the 1960s, various mechanisms including Master Chemical Mechanism (MCM), Carbon Bond Mechanism (CBM), Statewide Air Pollution Research Center (SAPRC) and Regional Atmospheric Chemistry Mechanism (RACM) have been developed for different research purposes. This work summarizes the development and applications of these mechanisms, introduces their compositions and lumping methods, and compares the ways the mechanisms treat radicals with box model simulations. CBM can reproduce urban pollution events with relatively low cost compared to SAPRC and RACM, whereas the chemical behaviors of radicals and the photochemical production of ozone are described in detail in RACM. The photolysis rates of some oxygenated compounds are low in SAPRC07, which may result in underestimation of radical levels. As an explicit chemical mechanism, MCM describes the chemical processes of primary pollutants and their oxidation products in detail. MCM can be used to investigate certain chemical processes; however, due to its large size, it is rarely used in regional model simulations. A box model case study showed that the chemical behavior of OH and HO2 radicals and the production of ozone were well described by all mechanisms. CBM and SAPRC underestimated the radical levels for different chemical treatments, leading to low ozone production values in both cases. MCM and RACM are widely used in box model studies, while CBM and SAPRC are often selected in regional simulations. 相似文献
330.
壳聚糖复合粘土矿凝聚铜绿微囊藻的研究 总被引:11,自引:0,他引:11
对壳聚糖与天然粘土矿物海泡石复配凝聚水体中铜绿微囊藻进行了研究 ,结果表明 :在壳聚糖用量为0 5 6mg L、海泡石用量为 32mg L的情况下 ,藻个数由 1 94 4× 10 6 个 mL降为 1 38× 10 3个 mL ,去除率达到 99 93% ;浊度由 6 5NTU降到 0 1NTU ,去除率达 99 6 % ;叶绿素a去除率达 10 0 % (用常规方法无法检测到 )。实验还确定了最佳pH值范围是 4~ 8;并且探讨了壳聚糖的絮凝机理。 相似文献