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81.
A novel ATP regeneration system using polyphosphate-AMP phosphotransferase and polyphosphate kinase 总被引:4,自引:0,他引:4
Kameda A Shiba T Kawazoe Y Satoh Y Ihara Y Munekata M Ishige K Noguchi T 《Journal of Bioscience and Bioengineering》2001,91(6):557-563
Polyphosphate-AMP phosphotransferase (PAP) and polyphosphate kinase (PPK) were used for designing a novel ATP regeneration system, named the PAP-PPK ATP regeneration system. PAP is an enzyme that catalyzes the phospho-conversion of AMP to ADP, and PPK catalyzes ATP formation from ADP. Both enzymes use inorganic polyphosphate [poly(P)] as a phosphate donor. In the PAP-PPK ATP regeneration system, ATP was continuously synthesized from AMP by the coupling reaction of PAP and PPK using poly(P). Poly(P) is a cheap material compared to acetyl phosphate, phosphoenol pyruvate and creatine phosphate, which are phosphate donors used for conventional ATP regeneration systems. To achieve efficient synthesis of ATP from AMP, an excessive amount of poly(P) should be added to the reaction solution because both PAP and PPK consume poly(P) as a phosphate donor. Using this ATP generation reaction, we constructed the PAP-PPK ATP regeneration system with acetyl-CoA synthase and succeeded in synthesizing acetyl-CoA from CoA, acetate and AMP. Since too much poly(P) may chelate MG2+ and inhibit enzyme activity, the Mg2+ concentration was optimized to 24 mM in the presence of 30 mM poly(P) in the reaction. In this reaction, ATP was regenerated 39.8 times from AMP, and 99.5% of CoA was converted to acetyl-CoA. In addition, since the PAP-PPK ATP regeneration system can regenerate GTP from GMP, it could also be used as a GTP regeneration system. 相似文献
82.
Mechanical properties of high purity polycrystalline cBN synthesized by direct conversion sintering method 总被引:7,自引:0,他引:7
Mechanical properties of high purity polycrystalline cBN sintered bodies synthesized by the direct conversion method under high pressure and high temperature have been investigated by hardness and transverse rupture strength (TRS) measurement in the temperature range of 20–1200 °C. It was confirmed that the hardness and TRS of the polycrystalline cBN depends strongly on the cBN grain size and the amount of residual (compressed) hBN in the sintered body. The fine-grained (<0.5 m) and high purity (cBN > 99.9%) polycrystalline sintered body synthesized at 7.7 GPa, 2200–2400°C has highest hardness and TRS at any temperature. The TRS of the sintered body shows a positive temperature dependence up to 1200 °C. The high hardness and high TRS at high temperature of the fine-grained high purity polycrystalline cBN suggest that the sintered body has high potential in cutting tool uses. 相似文献
83.
84.
Hiroshi Saeki Hiroyasu EgoTakahiro Watanabe Katsuya IshibashiTakafumi Satoh Kazuo Miyamoto 《Vacuum》2011,85(10):975-977
A new vacuum seal for a rectangular flange used in r.f. equipments, was developed. The vacuum seal consists of a recess with a flat surface, machined into a rectangular flange, a rectangular metal gasket with a raised projection on one face, and a mating flange with a recess and raised projection. No leak greater than 1 × 10−10 Pa m3/s was found in leak tests, before and after baking cycles (100 °C, 12 h). 相似文献
85.
Ken’ichiro Kita Masaki Narisawa Atsushi Nakahira Hiroshi Mabuchi Masayoshi Itoh Masaki Sugimoto Masahito Yoshikawa 《Journal of Materials Science》2010,45(1):139-145
The polymer blends of PCS (polycarbosilane) and PMHS-h (polymethylohydrosiloxane with high molecular weight) were prepared
by freeze-drying process of mixed benzene solution. Melt viscosity, mass loss, and gas evolution from prepared polymer blends
were analyzed. A polymer blend of HSah15 (15 mass% PMHS-h to PCS) was melt-spun to fiber form, curing by thermal oxidation
and pyrolyzed at various temperatures up to 1773 K. The obtained fibers were investigated by tensile tests, FE-SEM (field
emission scanning electron microscope) observation, and XRD (X-ray diffraction) analysis. After pyrolysis at 1273 K, there
were no pores in the cross section of the fiber derived from pure PCS; however, there were amounts of pores in the cross sections
of the fiber derived from HSah15. After pyrolysis at 1773 K, the coarse β-SiC (silicon carbide) crystals were formed on the
outside surface of the fiber derived from pure PCS; however, no remarkable β-SiC crystal were formed on the outside surface
of the fiber derived from HSah15. 相似文献
86.
Kiyoshi Minoura Shigeaki Mizushima Yasushi Asaoka Ichiro Ihara Eiji Satoh Sayuri Fujiwara Yasuhisa Itoh 《Journal of the Society for Information Display》2008,16(1):129-136
Abstract— A novel reflective color LCD without polarizers has been developed using a PDLC film and a retro‐reflector. Bright color images including moving images are achievable with ambient light. This novel LCD will enable the new application area of electronic paper. 相似文献
87.
Takeuchi K. Satoh S. Tanaka T. Imamiya K. Sakui K. 《Solid-State Circuits, IEEE Journal of》1999,34(5):675-684
A new, negative Vth cell architecture is proposed where both the erased and the programmed state have negative Vth. This architecture realizes highly scalable, excellently noise-immune, and highly reliable NAND flash memories. The program disturbance that limits the scaling of a local oxidation of silicon (LOCOS) width in a conventional NAND-type cell is drastically reduced. As a result, the scaling limit of the LOCOS width decreases from 0.56 to 0.45 μm, which leads to 20% isolation width reduction. The proposed cell is essential for the future scaled shallow trench isolated cells because improved program disturb characteristics can be obtained irrespective of the process technology or feature size. New circuit techniques, such as a PMOS drive column latch and a Vcc-bit-line shield sensing method are also utilized to realize the proposed cell operation. By using these novel circuit technologies, array noise, such as a source-line noise and an inter bit line capacitive coupling noise, are eliminated. Consequently, the Vth fluctuation due to array noise is reduced from 0.7 to 0.1 V, and the Vth distribution width decreases from 1.2 to 0.6 V. In addition to the smaller cell size and the high noise immunity, the proposed cell improves device reliability. The read disturb time increases by more than three orders of magnitude, and a highly reliable operation can be realized 相似文献
88.
Katsuhiko Satoh 《Thin solid films》2008,517(4):1411-1416
Molecular dynamics simulation was performed at constant temperature and pressure to investigate the effect of pressure on molecular dynamics for disc-shaped molecules. The generic Gay-Berne model, GB(0.345, 5.0, 1, 3), was used to study the phase transition behaviour, and translational and rotational dynamics, under two different reduced pressures P?, 10.0 and 20.0. Obvious shifts were detected in the transition temperatures. Both systems have the same phase sequence with different pressures: isotropic, discotic nematic and columnar phases. Translational motion is characterised by the parallel and perpendicular components of diffusion coefficients, with respect to the director in the orientational ordered phase. With regard to rotational dynamics, the correlation time of the first-rank orientational time autocorrelation function, which corresponds to end-over-end rotational motion of a molecule, has been investigated. A clear jump in the temperature dependence of the correlation time has been found at the isotropic-nematic phase transition point. The retardation factor g|| as a function of the reduced temperature T?/TNI? shows an apparent pressure effect on the rotational dynamics. 相似文献
89.
Masaru Ogura Susumu Kage Masayoshi Hayashi Masahiko Matsukata Eiichi Kikuchi 《Applied catalysis. B, Environmental》2000,27(4):L213-L216
Effect of second components on the catalytic performance of Pd/H-ZSM-5 zeolite (Pd: 0.4 wt.%) was evaluated by a durability test of NO reduction with CH4 at a relatively high temperature of 500°C in the presence of water vapor for a prolonged period. The Pd/H-ZSM-5 showed high stable activity for this reaction without H2O in the reactant feed, while immediate and irreversible deactivation was observed in the presence of H2O, resulting in no activity after 7 h. The second components such as Co, Rh, Ag, Ce, and Fe introduced individually to the Pd/H-ZSM-5 enhanced the durability, and in particular the addition of 3.3 wt.% Co led to a stable NO conversion for more than 40 h in the presence of H2O. 相似文献
90.
For the design of radio local distribution systems in densely built-up areas, estimating how many subscribers are in sight from a nodal station is important. This paper proposes a method for estimating probability of success of line-of-sight paths termed visibility. Method validity is confirmed bypractical field examinations. 相似文献