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91.
《Journal of Nuclear Science and Technology》2013,50(10):897-902
The helium isotope formation cross-section has been obtained for iron, tantalum and tungsten irradiated with protons at energies from the reaction threshold up to several GeV. The cross-section evaluation has been performed using the results of model calculations and by the analysis of available experimental data. The numerical calculations were carried out using the modified ALICE code and the CASCADE/INPE code. 相似文献
92.
Kyunghun Jung Yuta Yamamoto Shuichi Hasegawa 《Journal of Nuclear Science and Technology》2017,54(11):1261-1266
Excess micromotion of trapped calcium ions was detected and compensated in our linear Paul trap apparatus for trace isotope analysis. The micromotion was detected by Charge-coupled device (CCD). camera and radio frequency (rf) correlation method. We found that 230 and 2280 V of compensation voltages were needed for x- and y-axis compensation in our apparatus, respectively. The z-axis micromotion was confirmed by the experiment and its cause was investigated by finding a shape of z-axis confinement field. The confinement field was indeed distorted in our apparatus and it gave rise to the trapped ion to shift from potential center. And the micromotion of r-direction was transferred to the z-axis by the distorted confinement field. The z-axis micromotion was suppressed by increasing cap voltage of trap. 相似文献
93.
本工作建立了损耗同时存在于级联各级供料流、精料流与贫料流中的多组分级联的数学模型,提出了求解该类级联方程的数值方法。各级组分分流比不变的多组分级联称为准理想级联,得到了计算存在损耗的准理想级联中相对产品流、相对贫料流、级联中总物质流量以及产品流和贫料流中组分丰度的解析表达式。 相似文献
94.
M. Rubel J.P. Coad V. Philipps 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(4):711-717
First wall components in controlled fusion devices undergo severe modification by various physical and chemical processes arising from plasma-wall interactions: material erosion, its transport in the plasma and re-deposition. The intention of this work is to give a concise overview of key issues in the characterization of plasma-facing materials and components in tokamaks. The importance of surface analysis in studies of fuel inventory and material migration is presented. Experimental procedures and analysis methods are briefly reviewed with emphasis on ion beam techniques which play a prominent role in studies of wall components exposed to hot plasmas. Practical aspects in the analytical approach are addressed and special instrumentation used in these studies is described. 相似文献
95.
以(CH_3)_3SiOH羟基模拟Li_4SiO_4陶瓷表面羟基,研究了H_2O与(CH_3)_3SiOH羟基H的氢交换反应机理.采用HF, MP2方法,在3-21G和6-311G++H~(**)水平上优化了(CH_3)_3SiOH, H_2O, (CH_3)_3SiOH-H_2O复合物及氢交换反应过渡态的结构.计算了生成(CH_3)_3SiOH-H_2O复合物的反应热,探讨了氢交换反应的路径.结果表明,可以形成2种形式的(CH_3)_3SiOH-H_2O复合物,一种是H_2O的O原子与(CH_3)_3SiOH羟基的H原子作用形成的复合物,另一种是H_2O的H原子与(CH_3)_3SiOH羟基的O原子作用形成的复合物.MP2/6-311G++~(**)水平上,对基组重叠能(BSSE)进行校正后,上述2种复合物的反应热分别为20.046 5 kJ/mol和21.630 7 kJ/mol.有利的氢交换反应路径为:H_2O的H原子与(CH_3)_3SiOH羟基的O原子作用形成的复合物,然后H2O提供1个H原子、1个O原子,(CH_3)_3SiOH提供1个O原子、1个Si原子形成由O, H, O, Si 4个原子构成的四元环过渡态,最后H_2O的O原子与(CH_3)_3SiOH 的Si原子成键形成新的(CH_3)_3SiOH,而(CH_3)_3SiOH的Si-O键断裂,由(CH_3)_3SiOH的羟基和H_2O的1个H原子形成新的H_2O分子,MP2/6-311G++~(**)水平上,BSSE校正后,此路径的反应活化能为186.898 4 kJ/mol. 相似文献
96.
V. Švor?ík N. Kasálková K. Záruba L. Ba?áková V. Lisá H. Gbelcová A. Macková 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(11):1904-1910
Polyethylene (PE) was irradiated with inert Ar plasma, and the chemically active PE surface was grafted with Au nanoparticles. The composition and the structure of the modified PE surface were studied using X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS). Changes in the surface wettability were determined from the contact angle measured in a reflection goniometer. The changes in the surface roughness and morphology were followed by atomic force microscopy (AFM). The modified PE samples were seeded with rat vascular smooth muscle cells (VSMC) or mouse NIH 3T3 fibroblasts, and their adhesion and proliferation were studied. We found that plasma discharge and Au grafting lead to dramatic changes in the surface morphology and roughness of PE. The Au nanoparticles were found not only on the sample surface, but also in the sample interior up to the depth of about 100 nm. In addition, plasma modification of the PE surface, followed with grafting Au-nanoparticles, significantly increased the attractiveness of the PE surface for the adhesion and growth of VSMC, and particularly for mouse embryonic 3T3 fibroblasts. 相似文献
97.
对内蒙古白乃庙金矿区矿脉、围岩较系统的氧同位素分析及脉石英包裹体水氢同位素测定结果表明,脉石英的氧同位素δ~(18)O=+4.37~-1.19‰,其包裹体水氢同位素δD=-108.9~-133.8‰。结合其他资料,提出大气降水是本矿区成矿热液的主要组分,而强烈的构造破碎,花岗岩类侵入体的热力驱动及合适的矿源层,使这种热液能够淋滤矿质并在构造有利部位富集成矿。 相似文献
98.
Hiroshi Kamimura Tsuyoshi Hamada Shun-ichi Matsuno Hideki Ushio 《Journal of Superconductivity》2002,15(5):379-385
The present novel approach consists of two stages: in the first stage the many-electron states of a CuO6 octahedron or a CuO5 pyramid are calculated by the first-principles variational method, by taking into account the local distortions of a CuO6 octahedron or a CuO5 pyramid. In the second stage a metallic state is constructed in the presence of the local AF ordering constructed by the localized spins. In this metallic state the local distortions are treated in the mean field approximation, so that a pseudopolaronic effect is taken into account. Based on this approach, the hole-concentration dependence of T
c and the isotope effect are calculated for LSCO, and compared with experimental results. This approach leads to d-wave pairing mechanism. 相似文献
99.
油气源对比的原则暨再论长庆气田的气源——兼答《论鄂尔多斯盆地中部气田混合气的实质》 总被引:7,自引:2,他引:5
油气源对比应遵循的原则,首先是能够解释地质实际,其次应符合烃源岩评价结果,再次是合理解释地球化学对比指标。确定混源气的主要来源时应考虑不同种类样品所代表的储量的大小,并应合理确定端元气中次要组分对比指标的浓度和特征值,长庆气田奥陶系碳酸盐岩气藏天然气“主要来自石炭系”的观点证据更充分,可以合理解释气藏的分布,符合石炭系各类烃源岩的评价结果,并且能够解释奥陶系气藏气地球化学化学指标与石灰-二叠系的差异,相反,“奥陶系自生自储”的观点不能合理解释奥陶素气藏的分布,不符合奥陶系碳酸盐岩生烃评价结果,并且不能提供排他性的地球化学证明。 相似文献
100.
文章对^28Si同位素的应用背景进行概述,并介绍分离。^28Si同位素的几种具体方法和国内外的分离研究现状,认为同位素纯^28Si材料将会在未来的高级微电子芯片等领域中获得很好的发展。 相似文献