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111.
一种新的纳米结构--管状石墨锥 总被引:1,自引:0,他引:1
文章作者利用微波等离子体辅助化学气相沉积的方法在铁针尖上合成了一种新的纳米结构,并称之为管状石墨锥.管状石墨锥在外形上由多面锥体组成,其内部是同心的圆柱形石墨层,其空心的直径为几个纳米到几十个纳米.这些管状石墨层从内到外地逐渐变短,从而使得它们呈现出锥形外观.锥的顶角一般为6-7度左右,锥的尖端只有几个纳米大小,而锥的底部可达到微米量级.值得注意的是,组成管状锥体的石墨层具有惟一的手性,都表现为锯齿型。 相似文献
112.
采用共沉淀-凝胶法制备Ni—Cu—Al催化剂,以甲烷为气源利用化学气相沉积法制备内径为25-50nm的大孔径碳纳米管,研究了催化剂制备条件、反应温度以及反应气流速对碳纳米管和碳产率的影响。结果表明,甲烷流速为480~500mL/min,甲烷裂解温度为973K,在823K空气气氛下焙烧的催化剂用于制备碳纳米管得到的产量大于10g/次。 相似文献
113.
James L. Delattre 《Applied Surface Science》2006,252(10):3912-3919
Thin films of plasma-polymerized thiophene (PPTh) were deposited on cold-rolled steel substrates to improve adhesion to rubber compounds. PPTh films were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and atomic force microscopy. The ratio of carbon-to-sulfur found in PPTh films is 4:1, suggesting the monomer structure is generally intact, which was supported by FT-IR absorptions characteristic of polymerized thiophene rings. However, some fragmentation did occur to give acetylenic and aliphatic groups. Steel-rubber adhesion measurements, performed in accordance with the ASTM 429-B peel test, strongly depended on cleaning and pretreatment methods as well as film thickness. Best results were obtained on polished steel samples that were cleaned with acid, pretreated with a hydrogen/argon plasma, then coated with 50 Å of PPTh film. These samples exhibited a peel force of 14.3 N/mm, which is comparable to that of polished brass control samples. Depth-profiling XPS analysis of the rubber-steel interface showed the existence of an iron sulfide layer which is likely responsible for the strong adhesion. 相似文献
114.
Jim J. Choi 《International Journal of Infrared and Millimeter Waves》2005,26(10):1427-1436
Precise dielectric property measurements at a millimeter wave frequency band are attractive. A Fabry-Perot open resonator
consisting of hemispherical and plane mirrors, coupling holes is designed by the use of analytic theories and a numerical
simulation code. HFSS. Dielectric constant measurements on CVD diamonds are performed by a frequency variation method. Measurements
show that permittivity and loss tangent range from 5.59 to 6.46, and from 1.1 × 10−3, to 5.3 × 10−2. respectively, in the frequency range of 95–100 GHz depending on sample preparation of the CVD diamonds. 相似文献
115.
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117.
Os and Os–Pd nanoparticles supported on multi-walled carbon nanotubes were prepared by vacuum pyrolysis at 573 K using the
[Os3CO10(NCMe)2] and [Pd(acac)2] as precursors. The nanoparticles prepared showed a narrow size distribution (Os: 1.8 nm; Os–Pd: 4.3 nm) and were decorated
evenly on the surface of the nanotubes. By controlling the metal-to-nanotube ratio, Os nanotubes were prepared using the carbon
nanotubes as a template. The catalysis of Os–Pd nanoparticles towards CVD carbon nanotube synthesis was studied.
Dedicated to Professor Gunther Schmid on the occasion of his 70th birthday. 相似文献
118.
Hiroyoshi Kanai Tatsuya Yoshikawa Tadahide Sone Yasuo Nishimura 《Reaction Kinetics and Catalysis Letters》2002,75(2):213-224
Highly dispersed V2O5/SiO2(CVD catalyst) was prepared by the reaction of vaporized VO(OPri)3 with silica at 293 K, whose process was followed by an IR technique. The rate of propylene photooxidation increased with an increase in V2O5 loading for CVD catalysts, but leveled off for impregnated ones. The CVD catalysts were characterized by XAFS and photoluminescence spectroscopy. 相似文献
119.
Thermal Chemical Vapor Deposition technique is modified with the use of Argon gas flow inside the chamber as an alternative for vacuum and orientation of one end closed quartz test tube. The use of Argon gas not only simplified the experimental set up, but also made it ~ 18 % cost effective compared to the conventional set up. Field Emission Scanning Electron Microscopy micrographs show straight and long BNNTs along with some cotton like morphologies. Transmission electron microscopy revealed bamboo like structure inside the tube and ~0.34 nm interlayer spacing for highly crystalline nature of boron nitride nanotubes. X-ray photon spectroscopy shows B 1s peak at 191.08 eV and N 1s peak at 398.78 eV that represents h-BN. Whereas, Raman spectrum indicates a major peak at ~1379.60 (cm−1) that correspond to E2g mode of h-BN. 相似文献
120.