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CVD金刚石膜{100}取向在改进化学反应模型下生长的原子尺度模拟 总被引:2,自引:0,他引:2
建立了CVD金刚石膜{100}取向生长过程中的化学反应模型,表面吸附生长机制以沟槽处碳氢组元加入的机制为主,并用改进的KMC方法在原子尺度上模拟了该模型下(100)表面的生长过程,给出了衬底温度和甲基浓度等操作参数对膜质量的影响,结果表明,该化学反应模型能够较实际地揭示{100}取向CVD金刚石膜的生长。 相似文献
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Solid‐phase polymerization (SPP) reactors are used to increase the degree of polymerization (DP) during nylon 6,6 production. In previous articles, a reactor model with partial differential equations (PDEs) in time and two spatial dimensions was developed to describe dynamic changes in polymer property profiles (DP, temperature, and moisture content) over the height of the reactor and within the polymer particles. In the current article, a simplified model is developed by deriving appropriate expressions for heat‐ and mass‐transfer coefficients and performing a lumped heat‐ and mass‐transfer analysis. Using this approach, the radial dimension is removed from the PDEs, so that the effort required to solve the model equations is substantially reduced. Predictions of the complex and simplified models are compared through simulation of two different start‐up processes. Good agreement between simplified and complex models is obtained, indicating that the simplified model can be used in place of the complex model if the polymer properties profiles within individual particles are not of particular concern to the model user. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3701–3712, 2003 相似文献
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在选择三元共聚尼龙(PA)、聚氯乙烯(PVC)、丁腈橡胶(NBR)为主体材料,制备PA/PVC/NBR(10/30/60)三元共混弹性体的工作基础上,进一步探讨了填料品种和用量,共混温度,加料顺序等因素PA/PVC/NBR三元共混弹性体的影响。试验结果表明:在PA/PVC/NBR(10/30/60)共混体系中,补强型填料的补强效果优于非补强型的填料,6种填料补强效果依次是:快压出炭黑>半补强炭黑>白炭黑>活性重质,CaCO3>陶土>滑石粉,快压出炭黑的适宜用量是20-50份。在制备PA/PVC/NBR三元共混物时,适宜的共混温度是122-140℃,并且采用二段法混工艺制得的共混物性能优于采用一段法共混工艺。 相似文献
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F. Bianchi S. Cantagallo G. Consolati M. Laporta M. Pegoraro G. Tieghi L. Zanderighi 《应用聚合物科学杂志》2002,86(3):559-571
Four production steps, extrusion, blowing, stabilization, and finishing, are involved in the manufacture of biorented nylon 6 films. The films obtained after each step were studied by wide‐angle diffraction X‐rays, IR analysis, and density measurements. Orientation in the amorphous phase was evaluated by thermal retraction. Free volume was investigated by positron annihilation spectroscopy. Mechanical properties were tested by tensile tests, and permeability was tested with isopiestic permeameters. Quenching, after extrusion, generated an unstable γ crystalline phase and an amorphous phase. Blowing transformed the unstable γ phase into the thermodynamically stable α phase and increased the chain orientation; stabilization increased α phase crystals, favored hydrogen bond formation and, therefore, the mechanical properties, leaving unchanged the chain orientation; the final treatment increased the mechanical properties. The film permeabilities to O2, N2, and CO2 were practically unchanged after each production step; this result may be explained by considering that the nanoholes, present in the films and responsible for the diffusion inside the polymer, maintained practically constant their radius, whereas their number concentration decreased slowly after thermomechanical treatments. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 559–571, 2002 相似文献
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介绍尼龙6纺织梭专用料的配方、工艺、性能及加工和应用。实践表明专用料配方合理、工艺可行性能优良、以其注射成型的纺织梭性能可靠、生产效率高、使用寿命长、附加值高、完全可替代压缩水生产纺织梭,具有工业推广应用价值。 相似文献
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Yudong Wang Minying Liu Zhimin Wang Xiaoguang Li Qingxiang Zhao Peng‐Fei Fu 《应用聚合物科学杂志》2007,104(3):1415-1422
The crystallization process of a new polyamide, nylon 1313, from the melt has been thoroughly investigated under isothermal and nonisothermal conditions. During isothermal crystallization, relative crystallinity develops in accordance with the Avrami equation with the exponent n ≈ 2 based on DSC analysis. Under nonisothermal conditions, several different analysis methods were used to elucidate the crystallization process. The Avrami exponent n is greater in the isothermal crystallization process, indicating that the mode of nucleation and the growth of the nonisothermal crystallization for nylon 1313 are more complicated, and that the nucleation mode might include both homogeneous and heterogeneous nucleation simultaneously. The calculated activation energy is 214.25 kJ/mol for isothermal crystallization by Arrhenius form and 135.1 kJ/mol for nonisothermal crystallization by Kissinger method, respectively. In addition, the crystallization ability of nylon 1313 was assessed by using the kinetic crystallizability parameters G. Based on this parameter, the crystallizability of many different polymers was compared theoretically. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1415–1422, 2007 相似文献
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采用双螺杆挤出机通过熔融共混制备了尼龙6/(苯乙烯/丙烯腈/顺丁烯二酸酐)共聚物/玻璃纤维(PA6/SANMAH/GF)复合材料,测试了材料的拉伸强度、弯曲强度、弯曲弹性模量、缺口冲击强度、热变形温度、吸水率、熔点和熔融焓,并与GF增强PA6(PA6/GF)复合材料和GF增强PA6/(苯乙烯/丙烯腈)共聚物(PA6/SAN/GF)复合材料进行了性能对比。结果表明,在PA6与SANMAH的质量比为100:3—30时,PA6/SANMAH/GF复合材料的拉伸强度与PA6/GF复合材料相当,但高于PA6/SAN/GF复合材料,弯曲强度和弯曲弹性模量高于PA6/GF和PA6/SAN/GF复合材料.缺口冲击强度高于PA6/GF复合材料,但低于PA6/SAN/GF复合材料;在PA6与SANMAH的质量比为100:40时,PA6/SANMAH/GF复合材料的拉伸强度、弯曲强度和缺口冲击强度明显降低;在整个试验范围内,PA6/SANMAH/GF复合材料的热变形温度比PA6/GF和PA6/SAN/GF复合材料低4~7℃;吸水率随着SAN-MAH用量的增加而逐渐减小。 相似文献