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991.
Ankita Bose Nandini Das Somendra N. Roy Nitesh Goswami Soumitra Kar R.C. Bindal P.K. Tewari 《International Journal of Hydrogen Energy》2014
An all silica DDR (deca dodecasil rhombohedral) zeolite membrane with dense, interlocked structure has been developed for separation of H2 from HI/I2 mixture of HI decomposition reaction. In this work, the DDR zeolite membrane was synthesized on the seeded clay-alumina substrate within 5 days. The seeds were synthesized by sonication mediated hydrothermal process within short crystallization time which enhanced the nucleation for the membrane growth. The synthesized membranes along with seed crystals were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy (EDAX). The selectivity of hydrogen with respect to CO2 and Ar was evaluated by single gas permeation studies at room temperature. The tests for corrosion resistance were carried out upto 120 h with both support and DDR membrane at 130 °C which confirmed the stability of membrane under the harsh HI/I2 environment. 相似文献
992.
ABSTRACT The possibility of obtaining narrowly dispersed particles through the controlled aggregation of polymer latices has been investigated. Concentrated polystyrene, poly(styrene-co-acrylic acid) and poly(styrene-co-butadiene-co-acrylic acid) latices were aggregated through the addition cationic surfactant under stirring. The method under investigation was proven to be effective in obtaining 5-15 urn particles with a narrow size distribution and a strong control of the average size. The aggregation properties of polymer latices were related to their chemical nature (chemical structure of the polymer and surface chemistry); the trends observed were explained through calculations of the fundamental forces involved in this process. Important differences were found between the aggregation of the latices that contain acrylic acid as a comonomer and those without acrylic acid. Narrow size distributions, with geometric standard deviations between 1.2–1.35 were obtained only for the latices containing acrylic acid. It was shown that on the surface of these particles there is a hairy layer formed by the polyacrylic acid chains. The thickness of this layer is dependent on the chemical environment and temperature. Its presence was demonstrated by capillary viscometry and electrophoretic mobility measurements. 相似文献
993.
994.
根据河南油田目前存在的情况,开发了一种井下油水分离系统的双级水力旋流样机.利用人工神经网络(Artificial NeuralNetworks,ANN)建立起井下双级水力旋流器的数学模型,通过实验室内柴油以及河南油田实际油样测试,根据前后的分析比较来评估该人工神经网络模型的可靠性和有效性.经过最终实验分析,在并下可以实现两级串联油水分离,当流量控制在6m3/h以上,同时入口油滴粒径大于80μm时,分离器的分离效率最好,可以达到99.5%以上.室内实验分离后水中含油浓度小于50PPm,现场试验小于200PPm,远低于国外室内试验的400PPm指标,测量数据可靠,为其应用于实际生产提供了理论分析基础. 相似文献
995.
996.
《钢铁研究学报(英文版)》2016,(2):103-108
Boron-bearing magnetite concentrate is typically characterized by low grade of iron and boron (wTFe=51%-54%,wB2 O3=6%-8%),as well as the close intergrowth of ascharite phase and magnetite phase.A promising technology was proposed to separate iron and boron by coupling the direct reduction of iron oxides and Na activation of boron minerals together.The influence of Na2 CO3 as additive on the direct reduction of boron-bearing magnetite was studied by chemical analysis,kinetic analysis,XRD analysis and SEM analysis.The results showed that the ad-dition of Na2 CO3 not only activated boron minerals,but also reduced the activation energy of the reaction and pro-moted the reduction of iron oxides.Besides,the addition of Na2 CO3 changed the composition and melting point of non-ferrous phase,and then promoted the growth and aggregation of iron grains,which was conducive to the subse-quent magnetic separation.Thus,the coupling of the two processes is advantageous. 相似文献
997.
Structure–property relations of nylon‐6 and polytetramethylene glycol based multiblock copolymers with microphase separation prepared through reactive processing 下载免费PDF全文
Weibo Kong Yunyun Yang Zhimeng Liu Liang Jiang Changlin Zhou Jingxin Lei 《Polymer International》2017,66(3):436-442
A series of poly(urethane‐urea‐amide) thermoplastic elastomers (PUUAs) based on polytetrahydrofuran (polytetramethylene glycol, PTMG), nylon‐6 and 4,4′‐diphenylmethane diisocyanate were synthesized through reactive processing. This method solved the incompatibility of nylon‐6 and PTMG, and these model elastomers were used to gain insight into the structure–property relations of block polymers. The target products were solvent resistant, transparent and melting‐processable. Fourier transform infrared spectroscopy, XRD, DSC, TEM, dynamic mechanical analysis, tensile testing and TGA were used to study the structure, crystallization, morphology, mechanical properties and thermostability of the PUUAs. The Fourier transform infrared results proved the successful preparation of PUUAs from nylon‐6 and PTMG. TEM examination showed that all samples exhibit microphase separated morphology with the nylon‐6 domain dispersed in the PTMG phase. The results of tensile testing indicated that the elastomers exhibit excellent mechanical properties with stress at break and strain at break exceeding 40 MPa and 600% respectively. The TGA results implied that the PUUAs can be fabricated by transitional processing at proper temperature without any thermodegradation. These favorable features were related to the microphase separated structure of the PUUAs. © 2016 Society of Chemical Industry 相似文献
998.
Porous Perovskite Fibers – Preparation by Wet Phase Inversion Spinning and Catalytic Activity 下载免费PDF全文
Sandy Kaiser Erik Reichelt Sylvia E. Gebhardt Matthias Jahn Alexander Michaelis 《化学工程与技术》2014,37(7):1146-1154
Porous perovskite (LaMnO3) fibers were prepared by means of wet phase inversion spinning. The influence of different spinning procedures, slurry and coagulation bath composition on fiber shape and pore morphology was studied. The catalytic activity of the prepared fibers was tested for carbon monoxide oxidation as a model reaction in a differential recycle reactor. The results revealed that by suitable choice of process conditions porous catalytically active fibers can be prepared. Catalytic measurements confirmed that the catalytic fibers exhibit an open structure that allows full utilization of the catalytically active surface without intraparticle diffusional limitations. 相似文献
999.
《Journal of the European Ceramic Society》2014,34(10):2543-2551
Uranium–plutonium mixed oxides incorporating high amounts of plutonium are considered for future nuclear reactors. For plutonium content above 20%, a phase separation occurs, depending on the temperature and on the oxygen stoichiometry. Here, using an in situ fast X-ray diffraction device dedicated to radioactive materials, we evidenced a phase separation occurring during rapid cooling from 1773 K to room temperature at the rates of 0.05 and 2 K s−1 for two (U1−yPuy)O2−x compounds, with y = 0.28 and 0.45, under a reducing atmosphere. Optical microscopy reveals that the cooling rate impacts the microstructure of the fuel pellet by inducing severe macroscopic cracks. These results are important for using uranium–plutonium mixed oxides with high plutonium content as nuclear fuels. Considering the associated issues, they dictate a cautious attitude when defining their conditions of fabrication. 相似文献
1000.
《Journal of Nuclear Science and Technology》2013,50(6):577-580
A calculational model for a modified diffusion coefficient has been developed to incorporate the neutron streaming effect in heterogeneous low-density channels accurately into diffusion theory calculations. The model uses a supercell, and the axial and radial diffusion coefficients of the heterogeneous inner cell are so defined that they can reproduce Benoist's axial and radial diffusion coefficients of the supercell when the diffusion coefficient of the outer cell is given as 1/3 Σtr . In the case of the axial diffusion coefficient, the axial buckling effect is taken into account by modifying the neutron path length within the streaming channel in calculating the collision probabilities. This model has been applied to an RZ fast reactor Core model with a gas expansion module (GEM). By using the axial diffusion coefficient obtained with the presented model, calculational error of GEM worth was reduced to less than 1/7 compared to the formula of Rowlands and Eaton. 相似文献