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挥发性有机化合物(VOCs)作为大气污染物的主要来源日益受到关注.催化氧化技术被认为是最有效的VOCs降解方法之一,其核心是催化剂.氧化铈(CeO2)基催化剂因具有良好的储氧和释氧能力、价格相对低廉而备受关注.本文在论述CeO2基催化剂降解VOCs机理的基础上,分别从单一CeO2和CeO2基复合金属或金属氧化物两个方面... 相似文献
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YOU Ke-wei GE Yun-shan HU Bin NING Zhan-wu ZHAO Shou-tang ZHANG Yan-ni XIE Peng 《环境科学学报(英文版)》2007,19(10):1208-1213
The types and quantities of volatile organic compounds (VOCs) inside vehicles have been determined in one new vehicle and two old vehicles under static conditions using the Thermodesorber-Gas Chromatograph/Mass Spectrometer (TD-GC/MS).Air sampling and analysis was conducted under the requirement of USEPA Method TO-17.A room-size,environment test chamber was utilized to provide stable and accurate control of the required environmental conditions (temperature,humidity,horizontal and vertical airflow velocity,and background VOCs concentration).Static vehicle testing demonstrated that although the amount of total volatile organic compounds (TVOC) detected within each vehicle was relatively distinct (4940μg/m~3 in the new vehicle A,1240μg/m~3 in used vehicle B,and 132μg/m~3 in used vehicle C),toluene,xylene,some aromatic compounds,and various C_7-C_(12) alkanes were among the predominant VOC species in all three vehicles tested.In addition,tetramethyl succinonitrile,possibly derived from foam cushions was detected in vehicle B.The types and quantities of VOCs varied considerably according to various kinds of factors,such as,vehicle age, vehicle model,temperature,air exchange rate,and environment airflow velocity.For example,if the airflow velocity increases from 0.1 m/s to 0.7 m/s,the vehicle's air exchange rate increases from 0.15 h~(-1) to 0.67 h~(-1),and in-vehicle TVOC concentration decreases from 1780 to 1201μg/m~3. 相似文献
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本研究于2019年12月至2020年1月在5个区域大气本底站:临安、金沙、龙凤山、上甸子和瓦里关,同步采集了PM2.5样品,分析了其中的非极性有机物:多环芳烃、正构烷烃和藿烷类化合物。结果表明,上甸子和龙凤山的多环芳烃平均浓度显著高于其他站点,分别为35.2±25.6 ng/m3和27.5±16.8 ng/m3;藿烷类物质的浓度在上甸子和临安出现高值,分别为2.72±1.78 ng/m3和2.47±0.990 ng/m3;正构烷烃浓度以临安最高,为86.7±40.6 ng/m3。对各站点多环芳烃和藿烷类化合物采用比值法,正构烷烃采用主峰碳数(Cmax)、碳优势指数(carbon preference index,CPI)和植物蜡贡献率(% Wax Cn),结合主成分分析-多元线性回归模型(PCA/MLR)综合进行源解析。结果显示采样期间除瓦里关外,其余站点燃烧源均以化石燃料源为主,贡献率分别为临安(94.9%) > 金沙(75.3%) > 龙凤山(74.7%) > 上甸子(62.5%) > 瓦里关(35.6%)。后向轨迹聚类分析(HYSPLIT)和潜在源贡献因子分析法(PSCF)表明各站点主要受到外来传输气团的影响,并查明了各站点的潜在污染源区。对背景站点的研究表明,东北地区和京津冀地区PM2.5中非极性有机物来源相似,京津冀地区的生物质燃烧源贡献率高于东北地区;长江中下游地区化石燃料贡献率显著高于生物质燃烧;华中地区燃煤和交通排放源排放贡献率均低于长江三角洲地区;青藏高原地区生物质燃烧贡献率远高于其他地区。 相似文献
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PM2:5 samples were collected in a regional sampling network with three sites in Hong Kong and four sites in the adjacent inland
Pearl River Delta (PRD) or Guangdong Province during four months/seasons from 2002–2003. Trans-boundary transport between
Hong Kong and the inland PRD is inevitable under the influence of Asian monsoon. In summer, Hong Kong serves as the upwind
site of the inland PRD while during other seasons it is under the influence of continental emissions. Previous studies have recognized
the importance of using chemical signatures to differentiate local vs. regional contributions to air pollutants in Hong Kong such as the
CO/NOx ratio, ratios of different VOC species. In this study, detailed chemical speciation by gas chromatography-mass spectrometry
was performed with PM2:5 samples to identify new chemical signatures to distinguish aerosols in Hong Kong from those from the inland
PRD. Since Hong Kong is not influenced by the continental emissions from the inland PRD during summer, comparison focused on
chemical data obtained from this season for chemical signatures. The new ratios developed from the current study include LCPI/HCPI
ratio of alkanes (0.39 0.02 in Hong Kong vs. 0.78 0.08 in the inland PRD), pyrene to benzo[ghi]perylene ratio (0.97 0.21 in
Hong Kong compared to 0.20 0.06 in the inland PRD), and the ratio of 1,2-benzenedioic acid to 1,4-benzenedioic acid (1.8 0.1 in
Hong Kong vs. 0.6 0.05 in the inland PRD). Results from this study also revealed that Hong Kong was impacted by ship emissions
as reflected by substantially high V/Ni ratio (9 2) while this ratio was about 1–2 at all sites in the inland PRD, which is very close to
typical ratios from residual oil combustion. 相似文献
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调查了珠江三角洲典型皮革厂生产过程中不同车间PM10的污染水平,并采用超声萃取和GC-MS联用技术研究了PM10中半挥发性特征有机污染物的含量和成分谱.在所采集的PM10样品中共检测出46种有机化合物,包括苯酚类、醇类、多环芳烃类、酸类、酰胺类和酯类等;真皮水场车间、真皮涂饰车间和人造皮革车间的PM10浓度分别为678.5、 454.5和498.6 μg·m-3,其颗粒相中有机物质量浓度分别为10.04、 6.89和14.21 μg·m-3;真皮水场车间以酯类和酰胺类物质所占比重较大,分别为43.47%和36.51%,真皮涂饰车间以酯类和醇类物质所占比重较大,分别为52.52%和16.16%,人造革生产车间以酯类和酰胺类物质所占比重较大,分别为57.07%和24.17%;在得到的具体成分谱中,水场车间以9-十八碳烯酰胺含量最高,为26.15%,真皮涂饰车间以邻苯二甲酸二辛酯的含量最高,为44.19%,而人造革车间的丁烯二酸二(2-乙基己基)酯和1-羟基哌啶含量明显高于其它2个车间. 相似文献