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31.
Hiroyuki Nakahira Masakatsu Maruyama Hideshi Ueda Haruyasu Yamada 《The Journal of VLSI Signal Processing》1993,5(2-3):133-140
This paper describes an image processing system using Image Signal Multiprocessors (ISMPs) adapted to gray-level image preprocessing for image analysis and image enhancement. It is composed of four ISMPs, five 1H-delay-lines, two 512×512×8-bit frame memories, a video timing controller (VTC), two 256-word ×8-bit ×8-table Look Up Tables (LUTs) and 80 nsec/sampling A/D and D/A converters. This multiprocessor system performs convolution operations such as spatial filters, contrast enhancement, and binarization for gray-level images, thinning, thickening, pattern matching etc. for binary images, and image quality improvement for moving images such as T.V. images. Otherwise, it performs feature extraction operations such as area calculations, fillet coordination, and moment calculations for objective image data. Moreover, this system is capable of applying color image processing by using a multiboard system. 相似文献
32.
Hiroyuki Kumano Akio SaitoSeiji Okawa 《International Journal of Heat and Mass Transfer》2002,45(7):1467-1475
The direct contact melting of a porous material is investigated experimentally and analytically. The phase change material (PCM) is made of fine ice particles of a nearly uniform diameter, which is changed as a parameter. In the analysis, two models are proposed. One is calculated as the direct contact melting of a monolithic sample and another is treated as an assembly of the direct contact melting of the individual particles. As a result, it was found that the heat flux increased with the diameter, due to increase of permeability in a case of small diameter. But, in a case of large diameter, the heat flux decreased as the particle diameter increased because the direct contact melting occurred independently for the individual particles. 相似文献
33.
A phytoplankton model, which includes a carbon cycle combined with a constant current obtained by the computation of tidal currents, was applied to the coastal region (Hiroshima Bay, Japan). The transformation rate constants for the carbon cycle were experimentally evaluated.The seasonal variations of particulate and dissolved organic matter by the simulation model were reasonably consistent with the field data. Carbon concentration increased by primary production in the upper layer was approx. 10 times that augmented by loading of carbon from land at the shore in summer. Sinking plays an important role in the elimination of particulate organic matter. On the other hand, horizontal advection and turbulent diffusion are important factors for the diminution of dissolved organic matter. 相似文献
34.
Kazuyoshi Kataoka 《Progress in Nuclear Energy》1998,32(3-4):265-272
Small and Medium Reactors (SMRs) are attractive in developing countries because of their unique features such as: better suitability for smaller electric grids, lower investment cost, smaller components and equipment to facilitate modularization, etc. Furthermore, other factors induced by SMR implementation, such as technical transfer promotion, domestic infrastructure improvement, stabilization of energy cost, and environmental protection put SMRs into a more favorable position. From the nuclear plant suppliers, many SMR designs are available for a wide range of applications. A questionnaire study, which the IAEA conducted in 1996, confirmed that several countries are interested in SMRs and that some SMRs are already in the detailed design stage. A projection shows that the total nuclear capacity would increase in all regions that consist mainly of developing countries in the near future. For a timely and broad implementation of SMRs, information exchange and cooperation are indispensable between nuclear suppliers and buyers. The IAEA continues to play a role in encouraging and assisting development and practical application of SMRs for harmonization of energy demand and supply in developing countries. 相似文献
35.
Hiroyuki Sugiyama Takuto Sekiguchi Ryosuke Matsumura Shunpei Yamashita Yoshihiro Suda 《Multibody System Dynamics》2012,27(1):55-74
In railroad turnouts, geometries of tongue and crossing rails are very complex and their shapes are changing along the track.
Therefore, wheels are subjected to not only tread and flange contacts, but also the back-of-flange and top-of-flange contacts
in the case of spring switches of tram vehicles. For this reason, one needs to deal with significant jumps in contact points
for solving wheel/rail contact problems in turnout, and an accurate prediction of jumps in contact points is one of the most
important issues that need to be carefully handled in the dynamic simulation of vehicle/turnout interactions. In this investigation,
a numerical procedure that can be used for solving such a complex wheel/rail contact problem in turnout is proposed. In particular,
a combined nodal and non-conformal contact approach is developed such that significant jumps in contact points are detected
using the nodal search, while the exact location of contact point is then determined with continuous surface parameterizations
using non-conformal contact equations. With this combined nodal and non-conformal contact approach for the contact geometry
analysis of vehicle/turnout interactions, multiple look-up contact tables can be generated in an efficient way without losing
accuracy. Since detailed contact search is performed off-line to obtain look-up contact tables, significant changes in contact
points in turnout can be efficiently predicted on-line with tabular data to be interpolated in a standard way. Several numerical
examples are presented in order to demonstrate the use of the numerical procedure developed in this investigation. 相似文献
36.
Takaki Kanbara Takakazu Yamamoto Hiroyuki Ikawa Tomohiko Tagawa Hisao Imai 《Journal of Materials Science》1989,24(5):1552-1558
Porous and electrically conducting carbon-clay composites were prepared by firing mixtures of carbon powder (0 to 20 wt%) and clay minerals. They showed porosity of 50 to 65% and had high mechanical strength (compressive strength = 130 to 400 kg cm–2) as well as high resistance against thermal oxidation in air. Their electrical conductivity, , increased with increasing carbon content levelling off at about 20 wt% of carbon content to give a value of about 2 S cm–1. Formation of carbon chains is considered to be responsible for the electrical conduction in the composite, and a model to correlate the electrical conductivity with the carbon content has been proposed by modifying a model previously proposed by Scarisbrick. 相似文献
37.
Crystallization of potassium titanate from the amorphous phase 总被引:1,自引:0,他引:1
Tadashi Endo Hiroyuki Nagayama Tsugio Sato Masahiko Shimada 《Journal of Materials Science》1988,23(2):694-698
By using amorphous potassium titanates as the starting materials, a sintered body of K2Ti4O9 or K2Ti6O13 with porous and fibrous textures was prepared. K2Ti2O5 and a new phase, K6Ti4O11 were synthesized by the thermal reaction of KNO3 with TiO2 at 1000° C for 10 to 20 h. On leaching in water to expel excess of potassium ions, both phases became amorphous. After mixing and moulding these amorphous materials in the desired proportion, a sintered body containing fibrous crystals of K2Ti4O9 was readily fabricated by heating at 1000° C for 12 h. When 5 wt % B2O3 was added to the amorphous phases, single phase K2Ti6O13, with a fibrous texture grew well on heating at 1000° C for 12 h. Addition of PVA polymer to the amorphous phases was responsible for controlling the porosity of the sintered body, e.g. about 52% theoretical density at 20 wt% PVA polymer. The optimum conditions for preparing the amorphous phases were systematically examined and the effect of the chemical reaction environments, such as different crucible materials on the calcination of KNO3 and TiO2 were also discussed. 相似文献
38.
39.
Tsuyoshi Nakai Kiyofumi Yamada Hiroyuki Mizoguchi 《International journal of molecular sciences》2021,22(11)
Alzheimer’s disease (AD) is an age-related and progressive neurodegenerative disorder. It is widely accepted that AD is mainly caused by the accumulation of extracellular amyloid β (Aβ) and intracellular neurofibrillary tau tangles. Aβ begins to accumulate years before the onset of cognitive impairment, suggesting that the benefit of currently available interventions would be greater if they were initiated in the early phases of AD. To understand the mechanisms of AD pathogenesis, various transgenic mouse models with an accelerated accumulation of Aβ and tau tangles have been developed. However, none of these models exhibit all pathologies present in human AD. To overcome these undesirable phenotypes, APP knock-in mice, which were presented with touchscreen-based tasks, were developed to better evaluate the efficacy of candidate therapeutics in mouse models of early-stage AD. This review assesses several AD mouse models from the aspect of biomarkers and cognitive impairment and discusses their potential as tools to provide novel AD therapeutic approaches. 相似文献
40.
Hiroyuki?Y.?SuzukiEmail author Hidenori?Kuroki 《Metals and Materials International》2004,10(2):185-191
A new compacting method for powder materials is presented. High-Speed Centrifugal Compaction Process (HCP) utilizes centrifugal
force of about 10,000 g for the compaction. HCP is suitable for net shape compaction of fine sub-micron and nano-powders.
HCP possesses a unique compacting mechanism that is different from other colloidal processes including Pressure Casting (PC),
and has a number of useful characteristics. HCP has a higher compacting speed than PC, wide applicability for net shape formation,
as well as a defect removing function. Because of homogeneous and flawless green microstructure, HCP alumina shows superior
sinterability and higher strength and hardness than most of other aluminas.
This article is based on a presentation made in the symposium “The 3rd KIM-JIM Joint Symposium on Advanced Powder Materials“,
held at Korea University, Seoul, Korea, October 26–27, 2001 under auspices of The Korean Institute of Metals and Materials
and The Japan Institute of Metals. 相似文献