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61.
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63.
Effects of partial hydrogenation, epoxidation, and hydroxylation on the fuel properties of fatty acid methyl esters 总被引:1,自引:0,他引:1
Kapila Wadumesthrige Steven O. Salley K.Y. Simon Ng 《Fuel Processing Technology》2009,90(10):1292-1299
The properties of biodiesel depend on the chemical structure of individual fatty acid methyl esters (FAME). In this work the chemical structure of fatty acid chains was modified by catalytic hydrogenation, epoxidation and hydroxylation under controlled conditions. Hydrolysis of ester functionality or oxidation of fatty acid chain was not observed during these reactions. The properties of hydrogenated FAME strongly depend on the hydrogenation time. The total saturated fatty acid (SFA) percentage increased from 29.3% to 76.2% after 2 h of hydrogenation. This hydrogenated FAME showed higher oxidation stability and higher cetane number but poor cold flow properties. Formation of trans FAME was observed during hydrogenation. Both hydroxylation and epoxidation resulted in a decrease of unsaturated fatty acid methyl ester (UFA) fraction. The percentages of total unsaturated FAME decreased 39% in the epoxidation reaction and 44% in the hydroxylation reaction. The addition of hydroxyl groups to the unsaturated regions of the fatty acid chain yields biodiesel with better cold flow properties, increased lubricity and slightly increased oxidative stability. However, epoxy FAME shows some interesting properties such as higher oxidation stability, higher cetane number and acceptable cold flow properties, which met the limits of ASTM D6751 biodiesel specifications. 相似文献
64.
The effect of H2S on the rates of toluene hydrogenation of sulfided Mo, Ni, Ni---Mo and Ni---Mo---P/alumina catalysts has been determined at 6 MPa, 350°C over a large range of H2S partial pressure. In those conditions, Ni/alumina is nearly inactive. For the three other catalysts, similar trends are found with in particular no effect of H2S at high partial pressure. In the presence of NH3, the effect of H2S remains globally the same. 相似文献
65.
Jun Sik Kim Hak Ki Kim Sang Bong Lee Myoung Jae Choi Kyu Wan Lee Yong Kang 《Korean Journal of Chemical Engineering》2001,18(4):463-467
Characteristics of CO2 hydrogenation were investigated in a fluidized bed reactor (0.052 m IDxl.5 m in height). Coprecipitated Fe-Cu-K-Al catalyst
(dρ=75–90 Μm) was used as a fluidized solid phase. It was found that the CO2 conversion decreases but the CO selectivity increases, whereas the space-time-yield attains maximum values with increasing
gas velocity. The CO2 conversion has increased, but CO selectivity has decreased with increasing hydrogenation temperature, pressure or H2/CO2 ratio in the fluidized bed reactor. Also, the CO, conversion and olefin selectivity appeared to be higher in the fluidized
bed reactor than those of the fixed bed reactor.
Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8–10, 2001), dedicated to Prof. H. S. Chun on the occasion of his
retirement from Korea University 相似文献
66.
Simulation of gas exothermic chemical reaction in porous media reactor with lattice Boltzmann method
Exothermic reactor is the main part in a chemical heat pump. It involves complex multi-component exothermal chemical reaction in catalyst-filled porous media. The lattice Boltzmann method (LBM) is developed to simulate the characteristics of fluid flow, heat and mass transfer coupling chemical reaction in the exothermic reactor of the isopropanol/acetone/hydrogen chemical heat pump system. Fractal theory is used to structure a porous medium model in the reactor. The simulation results show that LBM is suitable for the simulation and the conversion has an optimal value with different inlet velocities. 相似文献
67.
刘大伟 《化学工业与工程技术》2012,33(3):7-9
将负载型催化剂Pd/SBA—15用于催化邻氯硝基苯加氢。考察了反应温度、催化剂用量对Pd/SBA—15催化性能的影响,并考察了催化剂的使用寿命。实验结果表明,Pd/SBA—15催化剂表现出很好的催化性能,有望应用于工业生产。 相似文献
68.
69.
Chen Xu Ye Song Linfeng Lu Chuanwei Cheng Dongfang Liu Xiaohong Fang Xiaoyuan Chen Xufei Zhu Dongdong Li 《Nanoscale research letters》2013,8(1):391
One-dimensional anodic titanium oxide (ATO) nanotube arrays hold great potential as photoanode for photoelectrochemical (PEC) water splitting. In this work, we report a facile and eco-friendly electrochemical hydrogenation method to modify the electronic and PEC properties of ATO nanotube films. The hydrogenated ATO (ATO-H) electrodes present a significantly improved photocurrent of 0.65 mA/cm2 in comparison with that of pristine ATO nanotubes (0.29 mA/cm2) recorded under air mass 1.5 global illumination. The incident photon-to-current efficiency measurement suggests that the enhanced photocurrent of ATO-H nanotubes is mainly ascribed to the improved photoactivity in the UV region. We propose that the electrochemical hydrogenation induced surface oxygen vacancies contribute to the substantially enhanced electrical conductivity and photoactivity. 相似文献
70.
The present study was carried out to asses performance of a Pd-monolith downflow bubble column (DBC) reactor, and compare it with that of the slurry and the fixed bed DBC. The selective hydrogenation of butyne-1,4-diol to cis-2-butene-1,4-diol over palladium catalyst was chosen as a model reaction. In principle, the monolith DBC allowed the reaction to take place under kinetic control regime. Comparison with DBC employing 5% Pd/C powder and 1% Pd-on-Raschig ring catalysts revealed a better performance of the monolith DBC (1% Pd loading) with advantage of smaller reaction volume and intensified reaction rate. In the monolith DBC, improved hydrogen transport was possible, as the interface between bubbles and the channel wall was very thin, thus, the length of the diffusion path was very short. In addition, the interfacial surface area at both gas–liquid and liquid–solid interface in the monolith was also very high. The reaction kinetics was well represented by the Langmuir–Hinshelwood mechanism. As an alternative to conventional three-phase reactors, the monolith DBC was simple due to its inherent characteristic operation and no specially designed device. 相似文献