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81.
Y. Castrillejo M. R. Bermejo A. M. Martínez C. Abejón S. Sánchez G. S. Picard 《Journal of Applied Electrochemistry》1999,29(1):65-73
The stability of indium chloride and oxide as well as the electrochemical behaviour of indium ions have been studied in the equimolar CaCl2–NaCl melt at 550 C by X-ray diffraction (XRD) and different electrochemical techniques, using molybdenum and tungsten wires as working electrodes. Voltammetric and chronopotentiometric studies showed signals attributed to the presence of three oxidation states of indium, i.e. 0, i and iii. The standard potential of the redox couples, as well as the solubility products of indium oxides have been determined, showing that In(iii) ions are completely reduced to monovalent indium by the indium metal according to the reaction: In () + 2 In 3 In () and that In2O is a strong oxide donor according to the reaction: In2O(s) 2 In() + O2- These results have allowed the construction of E-pO2– equilibrium diagrams summarising the properties of In–O compounds. The electrodeposition of indium was uncomplicated at Mo and W electrodes. Very good adherence of liquid indium to the electrode materials was observed, with the formation of Na–In alloys at highly reducing potentials, and there was no evidence of indium dissolution into the melt. Moreover, the voltammograms corresponding to the electrochemical In(iii)/In(i) exchange were well defined. The two electrochemical steps were found to be quasi-reversible, and the values of the kinetic parameters, ko and , for both reactions, as well as the diffusion coefficients, DIn(III) and DIn(I) were calculated. 相似文献
82.
83.
84.
V. P. Sinditskii 《Combustion, Explosion, and Shock Waves》2007,43(3):297-308
For model systems with known kinetics of elementary reactions (CH3NO2 and HN3), temperature ranges are established in which the rate-controlling reactions are the initial endothermic decomposition of
the starting material or the subsequent secondary reactions. Heat release in reactions of NO2, NO, and N2O with various fuels, such as CH2O, CO, H2, and HCN, is modeled to establish the kinetic parameters and nature of the rate-controlling reactions in gas flames of nitro
compounds. It is shown that the activation energy of the heat-release reaction due to the interaction of NO2 with a hydrocarbon fuel (which is characteristic of the first flame of nitro compounds) is in the range of 29–33 kcal/mole,
depending on the type of fuel. According to the calculations performed, the activation energy of the rate-controlling heat-releasing
process due to the deoxidation of NO and N2O (which is typical of the second flame of nitro compounds) is 43–58 kcal/mole. In the range of high pressures, where the
flames merge, the kinetic parameters of heat release are determined by the reactions of the most reactive nitrogen oxide NO2.
__________
Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 3, pp. 59–71, May–June, 2007. 相似文献
85.
以环氧氯丙烷为交联剂,将聚酰胺胺树状大分子(PAMAM)接枝到稻草基体上,利用FTIR、SEM、XRD、TG等对其结构进行了表征和分析。考察了其对Nd~(3+)、Sm~(3+)、La~(3+)稀土金属离子的吸附性能,探讨了吸附时间、稀土金属离子浓度、吸附温度、溶液pH等因素对吸附性能的影响。同时对吸附过程的动力学、吸附等温线和吸附热力学进行了研究。结果表明,所制备的吸附剂对Nd~(3+)、Sm~(3+)、La~(3+)稀土金属离子的吸附平衡时间约为4 h,平衡吸附量分别为47.14、40.11和50.12 mg/g。吸附过程符合拟二级动力学模型和Freundlich等温线,表明此吸附过程是属于化学吸附过程。吸附热力学研究表明,此吸附过程是自发进行的,同时吸附过程是一个混乱度增加的熵增过程。 相似文献
86.
The three-way catalyst promoters (Ce-Zr)O2, (Pr-Ce-Zr)O2 and (Pr-Zr)O2 were prepared by the sol-gel method. The reduction/oxidation behavior of these mixed oxides was compared. It is shown that the formation of (Pr-Zr)O2 cubic solid solution at high temperature up to 800 °C makes it more reducible, and that the ternary solid solution that formed in (Pr-Ce-Zr)O2 mixed oxides plays an important role in the reduction process. The catalytic performance tests reveal that the introduction of a small amount of praseodymium into (Ce-Zr)O2 favors the light-off temperature of C3H6 and NO and the effectiveness for NO conversion at the lean region. 相似文献
87.
The electrochemical reduction of 2-hydroxy-5-[(4-sulfophenyl)azo]benzoic acid, 2-hydroxy-5-[(3-sulfophenyl)azo]benzoic acid, 2-hydroxy-5-[(2-sulfophenyl)azo]benzoic acid and 2-hydroxy-5-azo-benzoic acid has been carried out in aqueous solutions at glassy carbon electrode using cyclic voltammetry and chronoamperometry. The position of sulfo substituent relative to azo bridge as well as pH of the solution have significant impact on the electrochemical behavior of these compounds. It has been proposed that these compounds are reduced predominantly as hydrazone tautomers resulting in corresponding hydrazo compounds. The overall electrochemical reduction follows DISP2 mechanism, ultimately leading to the 5-amino salicylic acid and sulfanilic acid. The rate determining step is the homogenous redox reaction between intermediate hydrazo compound and 5-amino salicylic acid quinoneimine. The mechanism is proposed in which activated complex of 5-amino salicylic acid quinoneimine and intermediate hydrazo compound is formed with the simultaneous loss of one proton. 相似文献
88.
The influence has been studied of the partial pressure of hydrogen (0–30 kPa) upon the coking rate of a Cr2O3/Al2O3 commercial catalyst during 1-butene dehydrogenation. Coke deposition has been analysed using a monolayer-multilayer reversible coke growth model (MMRC model). This model provides good fits to the experimental data, within the range of partial pressure of H2 studied, and allows us to estimate the main kinetic parameters involved in the coking-deactivation process. The results obtained reveal a dual effect of hydrogen: competition against 1-butene for the active sites and the removal of coke precursors from the catalyst surface. Bom effects diminish the coking rate as the H2 partial pressure is increased. 相似文献
89.
漆酶氧化还原介质系统的作用机理及其应用 总被引:12,自引:0,他引:12
对漆酶-氧化还原介质系统作用机理及其应用的研究进展进行了综述。漆酶的催化反应发生在铜离子形成的活性中心,当介质存在时通过介质中间体传导电子使得反应的速度加快,效率提高,氧化底物范围可进一步扩大。这种漆酶介质系统作为新型的生物制剂在纸浆漂白、纺织品生物整理、环保等方面具有重要的应用价值。 相似文献
90.
Numerical solution of viscous flow past a solid sphere with the control volume formulation 总被引:1,自引:0,他引:1
The control volume formulation with the QUICK finite difference scheme is used to solveincompressible liquid flow past a solid sphere in terms of stream function and vorticity.Several tech-nical points are addressed on improving the accuracy and efficiency of numerical simulation of similarproblems of fluid flow.In particular,the importance of suitable specification of the distortion func-tion to enforcing the far field boundarv conditions is emphasized. 相似文献