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981.
In this paper, we describe a document clustering method called novelty-based document clustering. This method clusters documents based on similarity and novelty. The method assigns higher weights to recent documents than old ones and generates clusters with the focus on recent topics.
The similarity function is derived probabilistically, extending the conventional cosine measure of the vector space model
by incorporating a document forgetting model to produce novelty-based clusters. The clustering procedure is a variation of the K-means method. An additional feature of our clustering method is an incremental update facility, which is applied when new
documents are incorporated into a document repository. Performance of the clustering method is examined through experiments.
Experimental results show the efficiency and effectiveness of our method. 相似文献
982.
A. Suzuki R. Hashido T. Urakabe A. Iwata M. Inoue H. Nagata 《Journal of the Society for Information Display》2001,9(1):51-56
Low‐temperature poly‐Si TFT data drivers for an SVGA a‐Si TFT‐LCD panel have been developed. The data drivers include shift registers, sample‐and‐hold circuits, and operational amplifiers, and drive LCD panels using a line‐at‐a‐time addressing method. To reduce the power consumption of the shift register, a dot‐clock control circuit has been developed. Using this circuit, the power consumption of the shift register has been reduced to 36% of that of conventional circuits. To cancel the offset voltage generated by the operational amplifier, an offset cancellation circuit for low‐temperature poly‐Si TFTs has been developed. This circuit is also able to avoid any unstable operation of the operational amplifier. Using this circuit, the offset voltage has been reduced to one‐third of the value without using the offset cancellation circuit. These data drivers have been connected to an LCD panel and have realized an SVGA display on a 12.1‐in. a‐Si TFT‐LCD panel. 相似文献
983.
We propose achromatic quarter-wave plates of a subwavelength grating structure. When the period of the grating structure is smaller than the wavelengths of the incident light, the structure is considered to be an optically anisotropic medium. The effective refractive indices strongly depend on the wavelengths, especially when the period is close to the wavelength. Using this feature, we can design a grating quarter-wave plate whose phase retardation is maintained at pi/2 for a wide wavelength range. A design method using the effective medium theory is described, and the wave plates designed were evaluated by numerical calculation with a rigorous electromagnetic grating theory. The calculation results led to the possibility of an achromatic quarter-wave plate whose retardation errors are smaller than 3 degrees for a +/-10% change in wavelength. 相似文献
984.
Yoshihisa Harada Takayuki Suzuki Kazumi Hirano Yoshiharu Waku 《Journal of the American Ceramic Society》2003,86(6):951-958
Tensile creep tests were conducted for an in situ single-crystal alumina/yttrium aluminum garnet (Al2 O3 /Y3 Al5 O12 (YAG)) binary system eutectic composite at temperatures between 1773 and 1873 K in air and in a moist environment having a water-vapor pressure range of 0.06–0.6 MPa, under a constant tensile stress range of 100–160 MPa. The Al2 O3 /YAG eutectic composite exhibited a stress exponent of 8–13, indicative of tensile creep behavior characterized by a dislocation back-stress mechanism. Water-vapor pressures ≤0.4 MPa led to a significant acceleration of creep rates as a result of enhanced dislocation mobility in the Al2 O3 and YAG phases. 相似文献
985.
Shogo Uesaka Ryohei Yamaoka Toshiki Sasaki Akihiro Chida Susumu Kawashima Toshiyuki Isa Satoshi Seo Yoshiharu Hirakata Shota Yatsuzuka Takayuki Ohide Masataka Nakada Shunpei Yamazaki Manabu Niboshi Yoshiyuki Isomura Yuto Tsukamoto Shinichi Kawato Katsuhiro Kikuchi Seiichi Mitsui 《Journal of the Society for Information Display》2014,22(12):603-612
In this study, the device structure of a white tandem organic light‐emitting diode (OLED) was changed to control the emission area and thereby achieve less luminance decay. A long‐life 13.5‐inch 4 K flexible c‐axis‐aligned crystal oxide semiconductor (CAAC‐OS) active‐matrix OLED with less color shift and high resolution was fabricated using this long‐life white OLED, transfer technology, and a CAAC‐OS field‐effect transistor. 相似文献
986.
A study was conducted to investigate fatigue failure criteria for adhesively-bonded joints under combined stress conditions. Two types of adhesively-bonded joint specimens were used: the scarf joint and the butterfly-type butt joint. Both types of joints have considerably uniform combined stress distributions in the adhesive layer. Furthermore, the stress distributions of these joints were analyzed by a finite element method. The results showed that the maximum principal, the von Mises equivalent and the maximum shear stresses in the uniform stress region of the adhesive layer at the endurance limit are correlated with the principal stress ratio. 相似文献
987.
Nanocomposite particles consisting of silica (inorganic core) and polyacrylate (organic shell) were prepared in a form of emulsion by a new and simple method—the emulsion polymerization of acrylic monomers in the presence of silica sol. The key technique of the present emulsion polymerization, which made the formation of the nanocomposites successful, is the usage of nonionic surfactant above its cloud point. The morphology of the composite was investigated by DLS, AFM, and TEM, which clearly showed formation of the core‐shell‐type particles. A transparent film was prepared by casting the emulsion, which showed high resistibility against organic solvents. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 659–669, 2006 相似文献
988.
Masanori Hirano Toyoko Joji Michio Inagaki Hiroyuki Iwata 《Journal of the American Ceramic Society》2004,87(1):35-41
Anatase-type TiO2 (titania) doped with iron up to 19.8 mol% was directly formed as nanometer-sized particles from acidic precursor solutions of TiOSO4 and Fe(NO3 )3 by simultaneous hydrolysis, under mild hydrothermal conditions at 180°3C. Iron content in the anatase-type TiO2 was much less than that of the starting composition of the precursor solutions because of slower hydrolysis rate of Fe(NO3 )3 than that of TiOSO4 at 180°3C. The XRD data, TEM selected-area diffraction patterns, and Mössbauer effect measurement showed that iron(III) formed a solid solution in the anatase-type TiO2 precipitates and that there was no iron oxide precipitated as secondary phase without making a solid solution with TiO2 present in the precipitates. Doping of Fe2 O3 into TiO2 shifted the phase transformation from anatase-type to rutile-type structure to a low temperature. On the phase transformation from anatase to rutile, iron oxide was precipitated as Fe2 TiO5 (pseudobrookite) phase. When the iron content was increased in the anatase phase, onset of optical absorption shifted to longer wavelengths, and absorption in the UV-light region and in the visible-light region over 400–600 nm clearly appeared in the diffuse reflectance spectra of the as-prepared Fe(III)-doped TiO2 . 相似文献
989.
This paper investigates the problem of minimizing an L/sub 2/-sensitivity measure subject to L/sub 2/-norm dynamic-range scaling constraints for one-dimensional (1-D) as well as a class of two-dimensional (2-D) state-space digital filters, where the 2-D digital filters are described by a transposed structure of the Fornasini-Marchesini second local state-space model. In each case, a novel iterative technique is developed to solve the constraint optimization problem directly. The proposed solution methods are largely based on the use of a Lagrange function and some matrix-theoretic techniques. Numerical examples are presented to demonstrate the effectiveness of the proposed techniques. 相似文献
990.
A new chlorination method using ZrCl4 in a molten salt bath has been investigated for the pyrometallurgical reprocessing of nuclear fuels. ZrCl4 has a high reactivity with oxygen but is not corrosive to refractory metals such as steel. Rare earth oxides (La2O3, CeO2, Nd2O3 and Y2O3) and actinide oxides (UO2 and PuO2) were allowed to react with ZrCl4 in a LiCl-KCl eutectic salt at 773 K to give a metal chloride solution and a precipitate of ZrO2. An addition of zirconium metal as a reductant was effective in chlorinating the dioxides. When the oxides were in powder form, the reaction was observed to progress rapidly. Cyclic voltammetry provided a convenient way of establishing when the reaction was completed. It was demonstrated that the ZrCl4 chlorination method, free from corrosive gas, was very simple and useful. 相似文献