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681.
682.
Vertical distribution of polycyclic aromatic hydrocarbons in atmospheric boundary layer of Beijing in winter 总被引:1,自引:0,他引:1
Shu Tao Yi Wang Shiming Wu Shuzheng Liu Han Dou Yanan Liu Chang Lang Fei Hu Baoshan Xing 《Atmospheric environment (Oxford, England : 1994)》2007,41(40):9594-9602
Air samples were collected using active samplers at various heights of 8, 15, 32, 47, 65, 80, 102, 120, 140, 160, 180, 200, 240, 280 and 320 m on a meteorological tower in an urban area of Beijing in two campaigns in winter 2006. Altitudinal distributions of polycyclic aromatic hydrocarbons (PAHs) in atmospheric boundary layer of Beijing in winter season were investigated. Meteorological conditions during the studied period were characterized by online measurements of four meteorological parameters as well as trajectory calculation. The mean total concentrations of 15 PAHs except naphthalene of gaseous and particulate phase were 667±450 and 331±144 ng m−3 in January and 61±19 and 29±6 ng m−3 in March, respectively. Domestic coal combustion and vehicle emission were the dominant PAH sources in winter. Although the composition profiles derived from the two campaigns were similar, the concentrations were different by one order of magnitude. The higher concentrations in January were partly caused by higher emission due to colder weather than March. Moreover, weak wind, passing through the city center before the sampling site, picked up more contaminants on the way and provided unfavorable dispersion condition in January. For both campaigns, PAH concentrations decreased with heights because of ground-level emission and unfavorable dispersion conditions in winter. The concentration ratio of PAHs in gas versus solid phases was temperature dependent and negatively correlated to their octanol–air partition coefficients. 相似文献
683.
本文简要介绍了美日英法四环境管理体制的状况,分析了四国在环境管理体制建设方面的有益经验及其对我国的启示。 相似文献
684.
应用发光菌测定有机化合物的毒性 总被引:11,自引:4,他引:11
本文介绍了化合物对发光菌半数抑制发光强度的毒性测定方法,测定了几十种芳烃类化合物的毒性,发现不同取代基或取代位置的芳烃毒性不同,并且对发光菌的毒性与对黑呆头鱼的毒性有相关性。 相似文献
685.
为有效提高水利工程建设的安全管理能力,基于SHEL(软件、硬件、环境、人员)模型,从4个角度划分出7个维度,设计了水利工程建设施工班组安全氛围量表;对湖南省湘江流域数个大型航电枢纽项目的各施工班组的工人进行问卷调研,并利用相关软件分析所收集的数据,采用探索性因子分析法确定安全氛围的维度.结果 表明:水利工程建设施工班组安全氛围的主要影响因素包括安全制度建设、设备设施管理、安全教育考核、事故预防与处理、人员沟通与态度5个方面;该量表从施工班组的角度出发,对安全氛围进行有效测量,可为水利建设单位的安全管理工作提供依据,提高安全管理水平. 相似文献
686.
Tong ZHANG Xing XIE Hongying HU Yudong SONG Qianyuan WU Zusheng ZONG 《Frontiers of Environmental Science & Engineering in China》2008,2(3):380-384
Cryptosporidium and Giardia are two typical species of pathogenic protozoans that seriously endanger water quality. Previous works indicated that detection
of Cryptosporidium and Giardia with modified United States Environmental Protection Agency (USEPA) method-1623 using a membrane filtration-elution for sample
concentration attained better recovery and lower cost compared to the USEPA method-1623. Several improvements of membrane
filtration-elution step as well as immunomagnetic separation (IMS) steps were investigated and an optimized method for detection
of Cryptosporidium and Giardia in wastewater reclamation system was recommended in this paper. The experimental results show that an overnight soak of the
membrane after scraping and vortex agitation before elution could enhance and stabilize the recovery. Increasing turbidity
to 4 NTU by adding kaolin clay before filtration could effectively improve the recovery of low-turbidity water. Washing the
concentrate after centrifugation and twice acid dissociation both reduced the impact of water quality to protozoan recovery.
Protozoans in different water samples were determined by this optimized method, and the recovery of Cryptosporidium and Giardia were above 70% and 80% respectively, much higher than the acceptance of method-1623.
__________
Translated from Environmental Science, 2006, 27(12): 2547–2552 [译自: 环境科学] 相似文献
687.
Zidan Yuan Xu M Xing Wu Guoqing Zhang Xin Wang Shaofeng Wang Yongfeng Jia 《环境科学学报(英文版)》2020,32(4):205-215
Tooeleite(Fe6(As03)4 SO4(OH)4·4 H_2 O) is widely precipitated for direct As(III) removal from sulfate-rich industrial effluents.However,whether or not Fe(III)-As(III)-Cl(-I) precipitate is produced in chloridizing leaching media for As immobilization is almost unknown.This work founded the existence of ferric arsenite(hydroxy)chloride as a new mineral for As(III)removal.Its chemical composition and solid characterization were subsequently studied by using scanning electron microscope with an energy dispersive spectrometer(SEM-EDS),X-ray diffraction(XRD),infrared(FT-IR),Raman spectroscopy and thermogravimetric(TG)curve.The results showed the formation of a yellow precipitate after 3-days reaction of Fe(III)/As(III) with molar ratio≈1.7 in chloride solution at pH 2.3 neutralized with NaOH.Compared with tooeleite,chemical analysis and solid characterization indicated that Cl(-I)replaces S04(-II) producing ferric arsenite hydroxychloride with formula Fe5(As03)_3-Cl_2(OH)4·5 H_2 O.This new plate shaped solid showed better crytallinity than tooeleite,although it has similar morphology and characteristic bands to tooeleite.The FT-IR bands at 628,964 cm-1 and the Raman bands at 448,610,961 cm-1 were assigned to Fe-O or As(Ⅲ)-O-Fe or As(Ⅲ)-O bending/stretching vibration,indicating that both arsenite and chloride substituted for the position of sulfate for ferric arsenite hydro xychloride produced due to the lack of the SO_4~(2-) vibrations.Cl-(I) also contributed to increase As removal efficiency in aqueous sulfate media under acidic pH conditions via the probable formation of sulfatechloride ferric arsenite. 相似文献
688.
Yanan Guan Lei Wang Shujuan Wang Yihao Zhang Jieying Xiao Xiaoli Wang Erhong Duan Lian Hou 《环境科学学报(英文版)》2020,32(11):25-34
Shijiazhuang, the city with the worst air quality in China, is suffering from severe ozone pollution in summer. As the key precursors of ozone generation, it is necessary to control the Volatile Organic Compounds (VOCs) pollution. To have a better understanding of the pollution status and source contribution, the concentrations of 117 ambient VOCs were analyzed from April to August 2018 in an urban site in Shijiazhuang. Results showed that the monthly average concentration of total VOCs was 66.27 ppbv, in which, the oxygenated VOCs (37.89%), alkanes (33.89%), and halogenated hydrocarbons (13.31%) were the main composite on. Eight major sources were identified using Positive Matrix Factorization modeling with an accurate VOCs emission inventory as inter-complementary methods revealed that the petrochemical industry (26.24%), other industrial sources (15.19%), and traffic source (12.24%) were the major sources for ambient VOCs in Shijiazhuang. The spatial distributions of major industrial activities emissions were identified by using geographic information statistics system, which illustrated the VOCs was mainly from the north and southeast of Shijiazhuang. The inverse trajectory analysis using Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) and Potential Source Contribution Function (PSCF) clearly demonstrated the features of pollutant transport to Shijiazhuang. These findings can provide references for local governments regarding control strategies to reduce VOCs emissions. 相似文献
690.
为探明新集矿区深层地下水离子组成及其演化特征,采集了研究区砂岩水和太灰水等共20个水样,测试分析常规离子和氢氧同位素数据,采用Piper三线图、相关性分析、离子比例系数与饱和指数等方法,探讨了研究区深层地下水水化学特征及其成因。结果表明:(1)研究区砂岩水为高矿化度水,平均矿化度为2 743. 73mg/L,水化学类型主要为Cl-Na型,太灰水多为中矿化度水,平均矿化度为1 468. 33mg/L,水化学类型主要为HCO3·Cl-Na型和Cl-Na型;(2)研究区地下水的补给不仅有大气降水和地表水,还有古气候条件下形成的古溶滤-渗入水,且由于矿物质与深层地下水的水岩作用使得氧同位素发生漂移;(3)含水层中主要发生的水岩相互作用有硅酸盐和蒸发盐岩的溶解及阳离子交替吸附作用,盐岩和石膏在研究区地下水中是反应性矿物,白云石和方解石的溶解在矿区地下水中呈过饱和状态。 相似文献