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101.
铝在碱性电解液中的阳极行为 总被引:4,自引:1,他引:3
用电化学方法研究了Al(99.999% ̄99.5%)在4mol/LKOH溶液中的阳极行为,结果表明:杂质(Fe,Si,Cu)含量递增,铝的传递电阻变小、腐蚀速度增大,达到稳定开路电位所需时间延长,但50℃时商业铝Al99.82%的极化程度最小,在-1.224V下有400mA/cm2大电流产生;温度升高而铝阳极的活化作用随之增强,但腐蚀也加剧;铝电极在5mmol/LNa2SnO3 4mol/LKOH中的浸泡时间为20min较适合;添加剂Na2SnO3对铝的腐蚀抑制、电化学性能改善都产生有利影响,其最佳浓度为5mmol/L。 相似文献
102.
对含钒钢渣中的钒在KOH亚熔盐介质中的溶出行为进行了研究,实验考察了反应温度、反应时间及碱渣质量比等因素对溶出过程的影响,并探讨了溶出机理. 结果表明,随反应温度、反应时间及碱渣比增加,钒的溶出率增加. KOH亚熔盐溶出含钒钢渣中钒的过程,是分解其中Ca2SiO4, Ca3SiO5, Ca2Fe2O5等固溶钒的物相,生成可溶性钒酸钾及不溶性的Ca(OH)2的过程. 并可通过控制浸出液中的KOH浓度避免钢渣中高CaO含量对钒沉淀的影响. 反应温度220~240℃、反应时间1 h、碱渣质量比为4时,钒浸出率高于90%. 与传统焙烧法相比,不仅显著降低了能耗,且提高了溶出效率. 相似文献
103.
Karel Komers Jaroslav Machek Radek Stloukal 《European Journal of Lipid Science and Technology》2001,103(6):359-362
The composition of the solutions of solid KOH in methanol has been measured by means of determinating the content of water in the equilibrium mixture. The dependence of the equilibrium reaction extent ζ1 and the concentration equilibrium constant Kc on the ratio of the initial amounts of methanol and KOH containing 0.164 and 16.27 wt‐% of water are determined and theoretically described. The concentration of CH3O¯ ions can be calculated with these results. This value is very important for the course of the alkaline catalyzed methanolysis of rapeseed oil to biodiesel, because the methoxide ions are the true catalyst of such a transesterification. 相似文献
104.
本研究以废纸脱墨污泥(DPS)为原料,采用热水和盐酸酸洗两次脱灰、KOH活化、球磨辅助,制备了具有薄层结构且富含介孔的脱墨污泥基活性炭(DPS-AC)。结果表明,DPS-AC制备的最佳工艺条件为:热水预处理和酸洗处理两次脱灰,KOH溶液浓度6.5 mol/L,固液比1∶2,炭化温度750℃,炭化时间90 min,250 r/min间歇式球磨180 min。在此条件下制备的DPS-AC碘吸附量达657.50 mg/g,亚甲基蓝吸附量达230.69 mg/g,比表面积达595.138 m~2/g,总孔容达0.646 cm3/g,平均孔径4.339 nm,介孔结构发达。 相似文献
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108.
Maw-Ling Wang Yen-Chun Liu 《Journal of the Chinese Institute of Chemical Engineers》2008,39(6):587-595
The S-alkylation (substitution on sulfur atom) of 2-mercaptobenzimidazole (MBI or ArSH) by allyl bromide (RBr) was successfully carried out in an aqueous solution of KOH/organic solvent two-phase medium. The reaction, which may take place either in the organic phase or on the interface, is greatly enhanced in the presence of KOH without the aid of quaternary salts as the catalyst to promote the reaction. No product was obtained from N-alkylation (substitution on nitrogen atom) during or after the reaction period by using a limited amount of allyl bromide (RBr) relative to that of MBI. Based on the experimental evidence, the kinetic behaviors and the characteristics of the reaction are sufficiently described by the pseudo-first-order rate law. The effects of the reaction conditions, including the agitation speed, the amount of KOH, volume of water, volume of dichloromethane, amount of allyl bromide, amount of 2-mercaptobenzimidazole, organic solvents and temperature on the conversion of allyl bromide and the apparent rate constants (kapp) were investigated in detail. Peculiar result is obtained in studying the effect of the volume of water on the conversion (or the reaction rate) in this work. Rational explanations are provided for the observed phenomena from experimental results. 相似文献
109.
Effects of micropore development on the physicochemical properties of KOH-activated carbons 总被引:2,自引:0,他引:2
Ru-Ling Tseng Szu-Kung Tseng Feng-Chin Wu Chen-Ching Wang 《Journal of the Chinese Institute of Chemical Engineers》2008,39(1):37-47
Effects of micropore development through varying the KOH/char ratio on the porous, electrochemical, electronic, and adsorptive properties for corncob-derived activated carbons (ACs) prepared by means of the KOH activation method were systematically compared. The pore properties of ACs, including BET surface area, total pore volume, micropore volume ratio, bulk density, and product yield based on the raw material were investigated to gain an understanding for the influence of KOH dosage on the pore development. Element analysis and temperature-programming desorption (TPD) were used to obtain the information of chemical composition and surface oxygen functional groups on ACs in order to propose the reaction mechanism of KOH activation. Based on the pore development, KOH-activated carbons can be classified into two groups: a combination of physical activation and chemical KOH etching at low KOH/char ratios (0.5-2) as well as chemically uniform etching at high KOH/char ratios (≥3.0). From the adsorption study for five organics with molecular weights varying from 129 to 466 g/mol, the specific adsorption capacity of ACs for organics is independent of their specific surface area. The specific capacitance of ACs reached a maximum as the KOH/char ratio was equal to 3, attributed to a compromise between the specific surface area and electronic resistance of ACs. 相似文献
110.
研究了以硫、丙醛以及丙二腈为原料,经关环反应、还原反应、缩合反应制得奥氮平的新工艺.考察了反应试剂、缩合剂、反应物配比、反应温度等因素的影响,得到了最佳工艺组合:关环反应温度取20~25℃;缩合反应以氢氧化钾为缩合剂,用邻硝基氟苯替代邻硝基氯苯合成关键中间体2-(邻硝基苯胺基)-3-氰基-5-甲基噻吩;2-(2-硝基苯胺基)-3-氰基-5-甲基噻吩与二氯亚锡投料比1:4.0,还原关环产物与N-甲基哌嗪投料比1:8.0.在优化条件下,奥氮平总收率为38%. 相似文献