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1.
G. Wang T. Ogawa F. Kunimasa M. Umeno T. Soga T. Jimbo T. Egawa 《Journal of Electronic Materials》2001,30(7):845-849
Hydrogen (H) plasma passivation effects on GaAs grown on Si substrates (GaAs on Si) are investigated in detail. H plasma exposure
effectively passivates both the shallow and deep defects in GaAs on Si, which improves both the electrical and optical properties.
It was found that the minority carrier lifetime is increased and the deep level concentration is decreased by the H plasma
exposure. In addition, after H plasma exposure, room temperature photoluminescence (PL) for Al0.3Ga0.7As/GaAs multiple-quantum-well (MQW) on Si is enhanced with a decrease in the spectral width. 相似文献
2.
形变铜中位错组态的电镜分析 总被引:1,自引:1,他引:1
本文用TEM衍射成像技术观察在室温下形变铜中位错胞结构的产生与发展,测定了胞壁厚及位错环尺寸等应变的变化规律,并探讨了胞尺寸与位错密度,流变应力之间定量关系的存在。 相似文献
3.
4.
G. P. Watson M. O. Thompson D. G. Ast A. Fischer-Colbrie J. Miller 《Journal of Electronic Materials》1990,19(9):957-965
As shown previously, the misfit dislocation density of strained epitaxial III–V layers can be significantly reduced by isolating
sections (via patterned etching) of a GaAs substrate before epitaxial growth. A disadvantage of this technique is that the
wafer surface is no longer planar, which can complicate subsequent device fabrication. As an alternative, we have investigated
growth of 350 nm of In0.5Ga{0.95}As by molecular beam epitaxy at two temperatures on substrates which were patterned and selectively damaged by Xe
ion implantation (300 keV, 1015 cm2). Selectively etched substrates were prepared as reference samples as well. The propagation of the misfit dislocations was
stopped by the ion-implanted regions of the low growth temperature (400° C) material, but the damaged portions also acted
as copious nucleation sources. The resulting dislocation structure was highly anisotropic, with dislocation lines occurring
in virtually only one direction. At the higher growth temperature (500° C) the defect density fell, but the ion damaged sections
no longer blocked dislocation glide. Images from cathodoluminescence and transmission electron microscopy show thatthe low
growth temperature material has a dislocation density of 70,000 cm-1 in the 110 direction and less than 10,000 cm-1 in the 110 direction. Ion channeling and x-ray diffraction show that strain is relieved in only one direction. The strain
relief is consistent with the relief derived from TEM dislocation counts and Burgers vector determination. However, even this
high dislocation count is not sufficient to reach the expected equilibrium strain. Reasons for the anisotropy are discussed. 相似文献
5.
采用原子力显微镜、干涉显微镜对水热法合成蓝宝石和天然绿柱石等宝石的表面微形貌进行了研究. 通过对宝石晶体中微尺度涡旋位错的表征和示踪, 初步证实涡旋位错是某些宝石矿物晶体又一重要的生长机制. 这暗示, 微尺度成矿流体的涡旋运移与晶相涡旋成核可能是地球成矿动力学体系中某些物质运动和存在的又一种重要的形式. 对晶体生长机理的研究现状和发展趋势予以了讨论. 相似文献
6.
7.
冷拔碳素钢丝的纤维组织及其亚结构 总被引:1,自引:1,他引:1
用光学显微镜、透射和扫描电镜观察、分析冷拔碳素钢丝的纤维组织及其亚结构的形貌和特点,指出它对钢丝力学性能及断裂行为的影响,对金属制品生产者和用户加深对材料的认识有重要的理论和实际意义 相似文献
8.
It is proposed that the twist in polyethylene chains that can result from crystallization and subsequent deformation aggregates at boundaries and becomes a template for further reorganization that results in the long period observed in polyethylene fibres. The observed lower density at the boundaries requires the transport of free volume to the twist boundaries. Dispirations, disclinations and dislocations are crystallographic defects that are involved in the necessary transport mechanism. Twist and bend, derived from the Eulerian angles which are computed from the sets of chain internal coordinates, relate the orientation of different segments of a chain. Twist and bend are useful for the characterization of both crystallographic defects and arbitrary conformations of polymer chains. Defects, along with folds, chain ends, and ordinary edge and screw dislocations provide a basis for interpretation of structure-property relationships in solid polyethylene. 相似文献
9.
M. H. Yoo 《Intermetallics》1998,6(7-8):597-602
Based on the recent studies of deformation twinning in ordered intermetallics, the general background on slip-twinning-microcracking relationships is established. Specific roles of deformation twinning in the generalized plasticity of polycrystals and the crack-tip microplasticity are discussed in terms of the local strain compatibility by invoking both ‘tension’ and ‘compression’ twins. Special examples are given for γ-TiAl, other L10 alloys, and Ti3Al of the D019 structure. Effects of composition, microstructure and temperature on defect properties that are relevant to the propensity of deformation twinning are discussed. 相似文献
10.
将9SiCr钢的粒状原始组织改变为片状,再经830℃淬火后,其马氏体形态为筐篮编结状。而传统工艺所获得的马氏体形态为针状.这种筐篮编结状马氏体是9SiCr钢中一种崭新的组织形态,其精细结构为平行成束的板条。亚结构为高密度缠结位错.它有良好的综合机械性能,强韧性高,耐磨性高。 相似文献