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21.
S. J. Pearton K. P. Lee M. E. Overberg C. R. Abernathy N. Theodoropoulou A. F. Hebard R. G. Wilson S. N. G. Chu J. M. Zavada 《Journal of Electronic Materials》2002,31(5):336-339
High concentrations (0.1–5 at.%) of Mn or Fe were introduced into the near-surface region (≤2000 Å) of 6H-SiC substrates by direct implantation at ~300°C. After annealing at temperatures up to 1000°C, the structural properties were examined by transmission electron microscopy (TEM) and selected-area diffraction pattern (SADP) analysis. The magnetic properties were examined by SQUID magnetometry. While the Mn-implanted samples were paramagnetic over the entire dose range investigated, the Fe-implanted material displayed a ferromagnetic contribution present at <175 K for the highest dose conditions. No secondary phases were detected, at least not to the sensitivity of TEM or SADP. 相似文献
22.
GaTe is a III–VI semiconductor which has layered structure with large anisotropy in electrical properties. Growth of single
crystals by the Bridgman technique permitted the measurement of thermoelectric power in orthogonal directions from which the
anisotropy of hole effective masses were determined for the first time. From resistivity and Hall effect measurements the
carrier activation energies and scattering mechanisms between 10–300°K were found.
Study of the temperature dependence of conductivity revealed a variety of conduction mechanisms including weak localization
below 20°K, hopping conduction between 20–50 K and band conduction in and across the layer planes atT>70 K. Weak localization was confirmed through observation of negative magnetoresistance. TheI–V characteristics showed quantized behaviour due to tunneling across potential barriers, which may be due to stacking faults
between layer planes as observed by TEM studies. 相似文献
23.
24.
ZHANG Zhaochun YUE Longyi GUO Jingkang 《稀有金属(英文版)》2006,25(3):253-259
Raman spectra of gallium phosphide (GAP) nanosolids (unheated and heat-treated at 598 and 723 K, respectively) were investigated. It was observed that both the longitudinal optical mode (LO) and the transverse optical mode (TO) displayed an asymmetry on the low-wavenumber side. The scattering bands were fitted to a sum of four Lorentzians which were assigned to the LO mode, surface phonon mode, TO mode, and a combination of Ga-O-P symmetric bending and sum band formed from the X-point TA + LA phonons, respectively. Analysis of the characteristic of surface phonon mode revealed that the surface phonon peak of the GaP nanosolids could be confirmed. In the infrared spectrum of the GaP nanoparticles, we observed the bands on account of symmetric stretching and bending of PO2, as well as stretching of Ga-O The Raman scattering intensity arising from the Ga-O-P linkages increased as increasing the heat-treatment temperature. 相似文献
25.
封装工业正在推动着印制线路板技术水平朝着半导体要求的方向发展。高密度印制线路板正广泛用于网络路由器、自动测试设备和服务器领域。高密度要求(>150 IO/cm~2)正成为客户的普通需求。为满足现有的高密度封装要求,由于线宽、线距和通孔孔径正接近传统制作极限,普遍的方法就是不断增加印制线路板的层数。这些特征正驱动着印制线路板在基材、图像转移、蚀刻、电镀、阻焊、测试流程和对位系统的变化。此文主要讲述了印制线路板特性的变化趋势和利用对位模式和雷利分布去预测满足高级对位要求的能力以及印制线路板各流程中有关对准度的控制要点。 相似文献
26.
Food products can be high‐pressure processed (HPP) either in bulk or prepackaged in flexible or semi‐rigid packaging materials. In the latter case the packaging material is subjected, together with the food, to high‐pressure treatment. A number of studies have been performed to quantify the effects of high‐pressure processing on the physical and barrier properties of the packaging material, since the integrity of the package during and after processing is of paramount importance to the safety and quality of the food product. This article reviews the results of published research concerning the effect of HPP on packaging materials. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
27.
Seong-Min Lee 《Metals and Materials International》2006,12(6):513-516
Based on empirical data, the present work provides a model to prevent filler-induced reliability degradation in plastic-encapsulated
LOC (lead-on-chip) packages. According to the model, the maximum size of the silica fillers included in the plastic package
body should be smaller than one half of the inter-distance between the device and its overlying lead-frame. In particular,
it is shown in the model that the spherical silica particles, which are sometimes trapped in the space between the top surface
of the device and the bottom of the lead-frame during the encapsulating process, can induce huge compressive stress on a specific
site of the integrated circuit pattern due to the thermal shrinkage of the plastic package body. Further, the present model
suggests that tiny fillers squeezed beneath a large trapping filler might directly attack the brittle layer of the device
pattern because the compressive force from the large filler particle can develop into huge compressive stress due to the reduced
load-carrying area. 相似文献
28.
Metal oxide semiconductors are today the most promising materials for photoelectrochemical production of hydrogen by the method of the photoelectrolysis of water as the problems of the stability of photoelectrodes are basically solved only for such materials. The aim of this short review paper is the presentation of results in this field obtained both worldwide and by the authors of this paper. The factors determining the efficiency of photoelectrolysis and possible ways to increase the photocatalytic activity of semiconductor photoelectrodes are analyzed. It is shown that the development of new photoelectrodes made of solid solutions and more complicated multicomponent compositions are most promising. Possibilities to use porous and nanocrystalline oxide photoelectrodes in photoelectrochemistry are also discussed. Photoelectrolysis setups for the photoelectrochemical conversion of solar energy into hydrogen are briefly described. 相似文献
29.
B. V. Korzoun L. A. Makovetskaya V. A. Savchuk V. A. Rubtsov G. P. Popelnyuk A. P. Chernyakova 《Journal of Electronic Materials》1995,24(7):903-906
Twenty alloys of various compositions in the Cu2Se-Al2Se3 system were prepared and investigated. The T(x) phase diagram of the Cu2Se-Al2Se3 system was obtained from x-ray diffraction, differential thermal analysis, and microstructure investigation for the first
time. The homogeneity region of the CuAlSe2 semiconducting compound was established.
Previous articles by this author were presented with the spelling of his name as B.V. Korzun. 相似文献
30.