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1.
The preparation of p-type amorphous- or microcrystalline silicon often requires the use of a gas mixture containing diborane. Whereas the concentration of this gas in the process chamber is critical for the determination of the doping level, and thus of the properties, of resulting films, it is in practice very difficult to have a proper control of such a concentration owing to the degradation of diborane in the cylinder by polymerisation. The main consequence is a significant lack of reproducibility of results. The present paper analyses the problem and its practical influence, describes a simple diborane-degradation model, proposes certain approaches based thereon and shows experimental results illustrating the validity of the procedures suggested. It is finally concluded that the application of this simple model is a straightforward and effective way to control diborane doping level in p-type amorphous- or microcrystalline silicon. 相似文献
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Farzan A. GhavaniniAuthor Vitae Maria Lopez-DamianAuthor VitaeDamon RafieianAuthor Vitae Krister SvenssonAuthor VitaePer LundgrenAuthor Vitae Peter EnokssonAuthor Vitae 《Sensors and actuators. A, Physical》2011,172(1):347-358
We explore the growth of vertically aligned carbon nanofibers by plasma enhanced chemical vapor deposition, using lithographically defined Ni catalyst seeds on TiN. TiN is selected for being an electrically conducting diffusion barrier suitable for the realization of electronic devices. We show that the rate of Ni diffusion correlates to both the level of oxygen content in the TiN film and to the film resistivity. The synthesis of the nanofibers was characterized using electron microscopy with an emphasis on three growth parameters: substrate temperature, plasma power, and chamber pressure. We propose that a catalyst surface free from carbon deposits throughout the process will induce diffusion-limited growth. The growth will shift towards a supply-limited process when the balance between acetylene, as the effective carbon bearing gas, and atomic hydrogen, as the main etching agent, is skewed in favor of acetylene. This determines whether the dominating growth mode will be vertically aligned ‘tip-type’ or disordered ‘base-type’, by affecting the competition between the formation of the first graphitic sheets on the catalyst surface and at the catalyst-substrate interface. 相似文献
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J.H. Lee 《Thin solid films》2006,515(3):917-921
SiOxNy thin films were deposited by inductively coupled plasma enhanced chemical vapor deposition (ICP-PECVD) using hexamethyldisilazane (HMDS, 99.9%)/NH3/O2/Ar at a low temperature, and examined for use as a water vapor diffusion barrier. The film characteristics were investigated as a function of the O2:NH3 ratio. An increase in the O2:NH3 ratio decreased the level of impurities such as -CHx, N-H in the film through a reaction with oxygen. Thereby, a more transparent and harder film was obtained. In addition, an increase in the O2:NH3 ratio decreased the nitrogen content in the film resulting in a more SiO2-like SiOxNy film. Using SiOxNy fabricated with an O2:NH3 ratio of 1:1, a multilayer thin film consisting of multiple layers of SiOxNy/parylene layers was formed on a polyethersulfone (PES, 200 μm) substrate, and its water vapor transmittance rate (WVTR) was investigated. A WVTR < 0.005 g/(m2 day) applicable to organic thin film transistors or organic light emitting diodes was obtained using a multilayer composed of SiOxNy (260 nm)/parylene (< 1.2 μm) on the PES. 相似文献
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Four kinds of silicon-metals (Cu, Ni, Sn)-graphite composites for anode active materials of lithium secondary batteries were
prepared by sequential employment of PECVD (Plasma enhance chemical vapor deposition) and RF(Radio-frequency)-magnetron sputtering
method. The silicon-copper-graphite composite showed the highest reversible capacity and cyclability among the silicon-metal
composite graphite samples prepared. The enhanced electrochemical performance of silicon-copper-graphite composite is attributed
to the formation of copper silicide on the surface of graphite.
The copper silicide plays an important role as a buffering layer against volume change of silicon during the intercalation/deintercalation
due to the chemical bonding of silicon and copper, and has lower interfacial impedance than that of other silicon-metal-graphite
composites which may lead to low irreversible capacity. 相似文献
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大面积应用的RF-PECVD技术研究 总被引:1,自引:0,他引:1
本文探讨采用小电极与大面积基片相对移动的方法来制造大面积薄膜的可行性,提出了采用小电极等离子体源在大面积基片上移动工作的新方法,可用于沉积(或刻蚀)均匀大面积薄膜或根据需求设计的大面积上非均匀膜厚分布的薄膜,从原理上避免大电极带来的不均匀性.介绍了这种方法中由两个电极构成的等离子体增强化学气相沉积(PECVD)系统.分析了当电极移动时,电极与真空室壁相对位置发生变化时对等离子体参数的影响.我们发现当两个射频电极之间的相位差为定值时,等离子体的分布随电极与真空室壁的距离(极-地距)变化而变化.当极-地距小于80mm时,随极-地距的增加,等离子体的悬浮电位和基片的自偏压下降,离子密度变化不明显.当极-地距大于80mm时,等离子体的分布呈稳定状态,各参数变化不明显.采用PECVD方法镀制了大面积薄膜厚度呈均匀分布和非均匀分布的两种薄膜,提供了膜厚呈线性渐变和抛物线变化的两种薄膜样片,显示了该方法的灵活性和可行性. 相似文献
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使用CF4和CH4为源气体,利用射频等离子体增强化学气相沉积(RF-PECVD)法制备了掺氟非晶碳(a-C:F:H)薄膜,并在N2气氛中进行了不同温度的退火.用原子力显微镜(AFM)观察了薄膜在退火前后表面形貌的变化,发现退火后薄膜表面变得平坦,疏松.用紫外-可见光透射光谱(UV-VIS)并结合傅里叶变换红外光谱(FTIR)和喇曼(Raman)光谱对薄膜进行了分析,获得了薄膜化学键结构和光学带隙的变化情况;发现薄膜的化学键结构和光学带隙与真空退火密切相关,高温退火后薄膜化学键结构:CHx(x=1,2,3下同)、F-芳基、CF2和CF等基团的含量改变;薄膜的光学带隙决定于CHx、退火后CHx含量减少导致薄膜光学带隙的减小. 相似文献
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