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131.
132.
Ivan Osipov Mikhail Y. Gorbachev 《Journal of environmental science and health. Part. B》2018,53(4):222-228
The photochemical degradation of vinclozolin by addition of titanium dioxide on silica support has been examined both experimental and quantum-chemically. Solar irradiation of vinclozolin on silica with and without addition of titanium dioxide for 6 h resulted in 21% and 97.8% vinclozolin residues, respectively. In both these cases, phototransformation leads to the formation of (3,5-dichlorophenyl isocyanate) and (3,5-dichloroaniline). The presence of the intermediary product resulted from opening of the 2,4-oxazolidine-dione ring is also confirmed by GS-MS and LC-MS chromatography. The proton-induced mechanism of vinclozolin decay at the above experimental conditions is clarified on the base of DFT calculations. 相似文献
133.
Periodically hydrologic alterations driven by seasonal change and water storage capacity management strongly modify physicochemical properties and chlorophyll-a (Chl-a) and their interactions in dam-induced lakes. However, the extent and magnitude of these changes still remain unclear. This study aimed to determine the effects of periodically hydrologic alterations on physicochemical variables and Chl-a in the dam-induced urban Hanfeng Lake, upstream of Three Gorges Reservoir. Shifts in Chl-a and 13 physicochemical variables were recorded monthly in the lake from January 2013 to December 2014. Chl-a was neither seasonal nor inter-annual differences while a few physical variables such as flow velocity (V) exhibited significantly seasonal variabilities, and chemical variables like total nitrogen (TN), nitrate-nitrogen (NO3-N), total phosphorus (TP), dissolved silica (DSi) were markedly inter-annual differences. Higher TN:TP (40:1) and lower NO3-N:DSi (0.8:1) relative to balanced stoichiometric ratios suggested changes in composition of phytoplankton communities and potentially increased proportion of diatom in Hanfeng Lake. Chl-a was predicable by combination of dissolved oxygen (DO), TN and DSi in dry season, and by V alone in wet season. During the whole study period, Chl-a was solely negatively correlated with TN:TP, indicating decline in N concentration and increase in P could therefore increase Chl-a. Our results highlight pronounced decoupling of linkages between Chl-a and physicochemical variables affected by periodically hydrologic alterations in dam-induced aquatic systems. 相似文献
134.
一起双氧水储罐爆炸事故的原因调查 总被引:2,自引:1,他引:1
错将水玻璃加到双氧水中,致使双氧水储罐爆炸,炸飞的罐体挂断供电线路,全厂断电停产23 h,经济损失100多万元,无人员伤亡. 相似文献
135.
136.
改性疏水硅胶用于油气吸附解吸的研究 总被引:1,自引:0,他引:1
吸附法为油气回收的常用方法,对吸附剂的研究有着重要的意义。为了开发出高吸附量、高热稳定性和疏水性的油气回收专用硅胶,对常规硅胶的物理及化学改性方法进行了研究。通过分析热处理温度、热处理时间及升温速度等因素对改性硅胶吸附效果的影响,提出了汽油油气吸附率高、吸水率低的硅胶改性条件为:酒石酸改性剂,热处理温度550~650℃,热处理时间3~10 h,升温速度3~10℃/min。同时,研究了影响改性硅胶解吸效果的因素,结果表明,真空度越高,温度越高,解吸次数越多,改性硅胶的解吸率越高。 相似文献
137.
以微硅粉为硅源,CTAB和PEG-6000为模板剂,制备得到MCM-41介孔分子筛,采用后接枝法将巯丙基三甲氧基硅烷引入到MCM-41的表面和孔道内,合成了巯基功能化的MCM-41介孔分子筛(SH-MCM-41)。采用TEM、N2吸附-脱附曲线、TG分析和XPS对样品进行了表征。以巯基功能化的样品为吸附剂,对含Cr(VI)的溶液进行了静态吸附实验,探讨了吸附过程的动力学。结果表明,SH-MCM-41对水中Cr(Ⅵ)的吸附经240 min可基本达到平衡,其理论吸附量为21.3 mg/g;利用准一级、准二级、Elovich方程、粒内扩散模型和班厄姆孔道扩散模型对吸附过程进行模拟,模拟结果表明,吸附过程符合准二级动力学模型,其拟合度R2为0.991,Elovich方程模拟相关系数R2大于0.95,表明吸附过程包含了多种反应机制。结果显示,吸附过程由液膜扩散、颗粒扩散和孔道扩散共同控制。 相似文献
138.
In this paper, experiments have been performed in order to determine the quantity of water produced from the atmospheric air using different desiccant materials named Silica gel, Activated alumina and Molecular sieve 13 X. On the bases of experimental results, a correlation is derived among the different temperatures and water production using Central Composite Design (CCD) of Response Surface Methodology. A newly designed solar glass desiccant box type system (SGDBS), three in number, has been used. Design parameters for the production of water has been taken as depth of material from the glass is 0.22 m, inclination in angle as 30°, effective thickness of glass as 3 mm and number of glazing as single. It has been found experimentally that the maximum quantity of water produced by Silica gel, Activated alumina and Molecular sieve 13 X is 160, 20 and 35 ml/kg/day, respectively. Whereas theoretically, value of water produced by the Silica gel, Activated alumina and Molecular sieve 13 X is 600, 28 and 60 ml/kg/day, respectively. 相似文献
139.
采用嫁接法制备了硅胶固载季鏻双三氟甲烷磺酰亚胺盐离子液体,并将其用于对CO2的吸附,考察了吸附剂的吸附等温线及循环使用性,并运用均相表面扩散模型(HSDM)研究了吸附动力学。采用FTIR和TG等技术对试样进行了表征。表征结果显示:离子液体已成功固载到硅胶上;煅烧活化硅胶对季鏻离子液体(C-Si O2-P4T)的固载量为5.39%(w);固载试样基本保持了硅胶的孔道特征。实验结果表明:C-Si O2-P4T具有较高的CO2平衡吸附量,且能显著提高CO2/N2吸附选择性,循环使用6次仍保持良好的吸附能力;HSDM可较好地拟合CO2在C-Si O2-P4T内的扩散行为,40℃下的扩散系数在10-7 m2/s数量级,与硅胶同级,优于纯季鏻离子液体。 相似文献
140.
以正硅酸乙酯(TEOS)作为包覆材料,对锰锌铁氧体纳米颗粒进行SiO2包覆,制备出锰锌铁氧体/SiO_2复合磁性材料。利用FTIR,XRD,SEM等技术对其进行了表征,并研究了其对模拟亚甲基蓝废水的吸附脱色效果。实验结果表明:当SiO_2质量分数为40%1时,采用先将锰锌铁氧体在柠檬酸溶液中搅拌分散3 h后,加人氨水调节溶液pH,再继续搅拌分散3 h的分段分散方法制备的复合磁性材料对亚甲基蓝废水的处理效果更好,处理亚甲基蓝质量浓度为50 mg/L、COD为160 mg/L的废水,废水脱色率为97.2%,COD去除率为19.3%。表征结果显示:复合磁性材料锰锌铁氧体/SiO_2为球形颗粒,平均粒径为100 nm;SiO_2包覆前后锰锌铁氧体的晶型均为尖晶石型结构,在复合磁性材料中SiO_2以无定型的形态存在。 相似文献