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271.
272.
壳聚糖三元接枝共聚物的合成及其阻垢性能 总被引:1,自引:1,他引:0
以壳聚糖(CTS)、衣康酸(IA)和马来酸酐(MA)为原料,以醋酸为溶剂、(NH_4)_2S_2O_8为引发剂,合成了CTS-IA-MA三元接枝共聚物。聚合反应的最佳条件为:反应温度90℃,n(CTS):n(IA):n(MA)=1:1.5:1.0,引发剂质量分数0.35%,反应时间5 h。通过傅立叶变换红外光谱(FTIR)表征,所得产物为CTS-IA-MA接枝共聚物。三元接枝共聚物质量浓度为50 mg/L、水样pH为中性或弱酸性时三元接枝共聚物对CaCO_3的阻垢效果较好。 相似文献
273.
274.
Elevated atmospheric deposition and dynamics of mercury in a remote upland forest of southwestern China 总被引:3,自引:0,他引:3
Xuewu Fu Wanze Zhu Heng Yao Hui Zhang 《Environmental pollution (Barking, Essex : 1987)》2010,158(6):2324-9448
Mt. Gongga area in southwest China was impacted by Hg emissions from industrial activities and coal combustion, and annual means of atmospheric TGM and PHg concentrations at a regional background station were 3.98 ng m−3 and 30.7 pg m−3, respectively. This work presents a mass balance study of Hg in an upland forest in this area. Atmospheric deposition was highly elevated in the study area, with the annual mean THg deposition flux of 92.5 μg m−2 yr−1. Total deposition was dominated by dry deposition (71.8%), and wet deposition accounted for the remaining 28.2%. Forest was a large pool of atmospheric Hg, and nearly 76% of the atmospheric input was stored in forest soil. Volatilization and stream outflow were identified as the two major pathways for THg losses from the forest, which yielded mean output fluxes of 14.0 and 8.6 μg m−2 yr−1, respectively. 相似文献
275.
276.
吸附增效低温等离子体法去除甲苯废气的研究 总被引:4,自引:1,他引:3
采用150Hz中频高压交流电源作为低温等离子体发生源,选用典型的微孔γ-Al2O3球形颗粒吸附剂(以下简称γ-Al2O3)作为等离子体反应器填充材料,协同低温等离子体法催化降解甲苯废气。考察了在不同条件下,γ-Al2O3的甲苯吸脱附效果和吸附增效低温等离子体法的甲苯去除效果。结果表明,甲苯降解反应主要发生在γ-Al2O3的表面,甲苯的去除率在一定的浓度范围内与γ-Al2O3表面吸附的甲苯量成正比关系;填充γ-Al2O3有利于提高甲苯去除率及等离子体反应器能量利用率;γ-Al2O3对臭氧的降解表现出一定的促进作用。 相似文献
277.
利用滨海新区2000—2007年人均GDP、单位GDP能耗及能源消费总量等指标的时间序列数据,拟合现状滨海新区能源消费环境库兹涅茨曲线(EKC)。基于情景分析法,预测了2006—2020年滨海新区经济发展与能源消耗响应关系及发展趋势,并对其EKC曲线形状做了进一步分析。结果表明,现阶段滨海新区能源消费总量与人均GDP相关关系不存在EKC假说,并且按目前发展态势,未来能源消费总量仍趋于不断增长。通过强有力的技术进步、结构调整、可再生能源开发利用以及相关法律、政策干预等措施,滨海新区可以在较低的人均GDP水平实现能源消费总量与经济增长的完全"脱钩"。 相似文献
278.
CeO_2/Al_(0.2)Ti_(0.6)Zr_(0.2)O_(1.9)/ATS复合脱硝催化剂的制备及其抗硫抗水性能研究 总被引:1,自引:1,他引:0
将预先经酸处理的铝钛硅(ATS)多相陶瓷片先后负载Al0.2Ti0.6Zr0.2O1.9复合氧化物与CeO2活性组分,制得新型CeO2/Al0.2Ti0.6Zr0.2O1.9/ATS复合脱硝催化剂。运用X射线衍射(XRD)、扫描电镜(SEM)手段对该催化剂进行表征,研究催化剂的晶相、微观形貌。评价了催化剂的脱硝活性,研究了H2O和SO2对其脱硝活性的影响。实验结果表明,CeO2/Al0.2Ti0.6Zr0.2O1.9/ATS具有良好的脱硝活性,高活性温度窗口在100~350℃,当反应温度为250℃时,NO的转化率达98.49%。SO2和H2O在一定程度抑制该催化剂的低温脱硝活性,但随着温度的升高,其脱硝活性逐渐恢复。催化剂中活性组分CeO2具有储硫作用,当有SO2存在时,活性温度窗口向高温区偏移了100℃,在250~400℃时,H2O的存在反而提高了催化剂的脱硝活性。 相似文献
279.
Renbin Zhu Yashu Liu Hua Xu Tao Huang Jianjun Sun Erdeng Ma Liguang Sun 《Atmospheric environment (Oxford, England : 1994)》2010,44(3):304-311
During the summertime of 2007/2008, carbon dioxide (CO2) and methane (CH4) fluxes across air–water interface were investigated in the littoral zones of Lake Mochou and Lake Tuanjie, east Antarctica, using a static chamber technique. The mean fluxes of CO2 and CH4 were ?70.8 mgCO2 m?2 h?1 and 144.6 μgCH4 m?2 h?1, respectively, in the littoral zone of Lake Mochou; The mean fluxes were ?36.9 mgCO2 m?2 h?1 and 109.8 μgCH4 m?2 h?1, respectively, in the littoral zone of Lake Tuanjie. Their fluxes showed large temporal and spatial dynamics. The CO2 fluxes showed a significantly negative correlation with daily total radiation (DTR) and a weakly negative correlation with air temperature and water temperature, indicating that sunlight intensity controlled the magnitude of CO2 fluxes from the open lakes. The CH4 fluxes significantly correlated with local air temperature, water table and total dissolved solids (TDS), indicating that they were the predominant factors influencing CH4 fluxes. Summertime CO2 budgets in the littoral zones of Lake Mochou and Lake Tuanjie were estimated to be ?152.9 gCO2 m?2 and ?79.7 gCO2 m?2, respectively, and net CH4 emissions were estimated to be 312.3 mgCH4 m?2 and 237.2 mgCH4 m?2, respectively. Our results show that shallow, open, alga-rich lakes might be strong summertime CO2 absorbers and small CH4 emitters during the open water in coastal Antarctica. 相似文献
280.
Increasing evidence has demonstrated toxic effects of vehicular emitted ultrafine particles (UFPs, diameter < 100 nm), with the highest human exposure usually occurring on and near roadways. Children are particularly at risk due to immature respiratory systems and faster breathing rates. In this study, children’s exposure to in-cabin air pollutants, especially UFPs, was measured inside four diesel-powered school buses. Two 1990 and two 2006 model year diesel-powered school buses were selected to represent the age extremes of school buses in service. Each bus was driven on two routine bus runs to study school children’s exposure under different transportation conditions in South Texas. The number concentration and size distribution of UFPs, total particle number concentration, PM2.5, PM10, black carbon (BC), CO, and CO2 levels were monitored inside the buses. The average total particle number concentrations observed inside the school buses ranged from 7.3 × 103 to 3.4 × 104 particles cm?3, depending on engine age and window position. When the windows were closed, the in-cabin air pollutants were more likely due to the school buses’ self-pollution. The 1990 model year school buses demonstrated much higher air pollutant concentrations than the 2006 model year ones. When the windows were open, the majority of in-cabin air pollutants came from the outside roadway environment with similar pollutant levels observed regardless of engine ages. The highest average UFP concentration was observed at a bus transfer station where approximately 27 idling school buses were queued to load or unload students. Starting-up and idling generated higher air pollutant levels than the driving state. Higher in-cabin air pollutant concentrations were observed when more students were on board. 相似文献