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991.
Wen Ling Chu Xiang Guang Yang Xing Kai Ye Yue Wu 《Reaction Kinetics and Catalysis Letters》1997,62(2):333-337
Heteropolyacids (HPAs) supported on the activated carbon (SiW12/C and PW12/C) have been used to study the formation of methyltert-butyl ether (MTBE). Compared to the conventional commercial catalyts, Amberlyst-15 resin and HZSM-5, HPAs supported catalysts
have been proved to have much higher catalytic activity under lower temperature, esperically selectivity to MTBE is up to
100%. It may be due to the high acid strength of HPAs as well as the specialty of heteropolyanion. 相似文献
992.
Vaibhav B. Valodkar Gopal L. Tembe Marayil Ravindranathan Rajnath Ram Hoskote S. Rama 《Reaction Kinetics and Catalysis Letters》2003,80(2):285-291
L-phenyl alanine was anchored to P(S-DVB) resin and its complex with PdCl2 was prepared. The newly synthesized catalyst was found to be a versatile and recyclable catalyst for the hydrogenation of
1-octene and acetophenone. This chiral catalyst induced moderate enantioselectivity during the asymmetric reduction of acetophenone.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
993.
CO2与CH4催化反应合成气研究 总被引:11,自引:0,他引:11
CO_2与液化天然气(98%为C_3-C_4烃)催化重整制合成气,八十年代初期在当时的西德已建立了工业生装置.近年来,由于石油资源日趋短缺,促进世界各国重视探讨和研究天然气资源利用的新途径.除甲烷氧化偶联制乙烯,甲烷氧化制甲醇和甲醛等直接转化过程已引起广泛的重视外,研究和开发由甲烷制取合成气的新过程也正日益受到人们的关注,其中利用CO_2与甲烷催化重整制合成气,可将造成温室效应,破坏人类生存环境的CO_2气体转化为宝贵的化工原料,所制得的合成气中CO/H_2=1,特别适合做羰基合成和合成有机含氧化合物的原料,近年来对该反应的研究已引起人们的重视.其反应表示如下: 相似文献
994.
K2O对合成DMC用Cu-Ni/V2O5-SiO2催化剂性能的影响 总被引:3,自引:0,他引:3
V2O5 SiO2(VSiO) supported Cu Ni K2O catalysts for the synthesis of dimethyl carbonate were prepared using isovolumic impregnation. Based on TPR,TPD, IR and micro reactor techniques, the effect of K2O on the adsorption and reaction of CO2 and CH3OH on the catalyst were characterized. The results show that addition of K2O exerts obvious influence on the charge distribution of the active sites on Cu Ni/VSiO catalyst,increases the intensities of CO2 horizontal adsorption state, while that of the dissociation state of methanol descends. When the ratio of K is above 15 %, K2CO3 is formed on the catalyst. Moreover,the main reaction products of CO2 and CH3OH on Cu Ni K2O/VSiO catalyst are still DMC, H2O, CO and CH2O,and with the addition of K2O, the conversion of reactants rise, but the selectivity of by-products decreases. 相似文献
995.
996.
Pei Jing Tao Gan Hui Qi Bin Zheng Xuefeng Chu Guiyang Yu Wenfu Yan Yongcun Zou Wenxiang Zhang Gang Liu 《催化学报》2019,40(2):214-222
An efficient and low-cost supported Pt catalyst for hydrogenation of niroarenes was prepared with colloid Pt precursors and α-Fe2O3 as a support. The catalyst with Pt content as low as 0.2 wt% exhibits high activities, chemoselectivities and stability in the hydrogenation of nitrobenzene and a variety of niroarenes. The conversion of nitrobenzene can reach 3170 molconv h?1 molPt?1 under mild conditions (30 °C, 5 bar), which is much higher than that of commercial Pt/C catalyst and many reported catalysts under similar reaction conditions. The spatial separation of the active sites for H2 dissociation and hydrogenation should be responsible for the high chemoselectivity, which decreases the contact possibility between the reducible groups of nitroarenes and Pt nanoparticles. The unique surface properties of α-Fe2O3 play an important role in the reaction process. It provides active sites for hydrogen spillover and reactant adsorption, and ultimately completes the hydrogenation of the nitro group on the catalyst surface. 相似文献
997.
Silca-supported Co3O4 (6 wt% as Co) catalysts were prepared by pore volume impregnation of ethanol or aqueous cobalt nitrate solutions, and calcined in vacuo to 300 °C. The catalytic performances of these catalysts for oxidation and hydrogenation of CO were examined. All Co3O4/SiO2 catalysts were found to be very active in catalyzing oxidation of CO to CO2 as compared to a commercial 1 wt% Pt/Al2O3. The ethanol-prepared catalysts exhibited higher activity than those of the aqua-prepared catalysts. Pre-calcination of the ethanol-prepared catalysts in oxygen at 600 °C resulted in a dramatic decrease in the activity. Temperature programmed oxidation indicated the presence of carbon deposits on the surface of used catalysts. Infrared spectra showed the continuous generation of CO2 when these catalysts were exposed to CO. These indicate the primary role of CO disproportionation in catalytic oxidation of CO on Co3O4 at low temperature and explain the sharp decrease in activity in the initial period. After reduction at 400 °C, the ethanol-prepared catalysts were also found to be more active in catalyzing hydrogenation of CO, and produced less methane and olefin (C2-C4) fraction. Higher turnover frequencies were observed after high temperature reduction (600 °C) as well, at which ethoxyl groups were removed from silica surface. In both reactions, the enhanced activity for the ethanol-prepared catalysts can not be fully accounted for by the increase in the dispersion of Co3O4 or CO metal. This suggests that the surface structures of Co3O4 or CO were further modified by the carbonaceous species derived from ethanol. 相似文献
998.
AHTD法铜基催化剂中氧化铝的作用 总被引:3,自引:0,他引:3
由合成气催化合成甲醇是重要的工业过程,其中使用的Cu/Zn/Al催化剂一直是人们广泛研究的对象,这种催化剂常由金属硝酸盐用NaHCO_3(或Na_2CO_3)在一定的pH值下沉淀生成金属复合碳酸盐,再加热分解成氧化物制得。该法步骤繁琐,耗时多。本文采用雾化高温分解法(Aerosol High Temperature Decomposition,简称AHTD法)扶金属硝酸盐一步制得催化剂氧化物,并研究了Cu/Zn/Al催化剂中Al_2O_3对催化活性、表面性质的影响。 相似文献
999.
1000.