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131.
Yasuyoshi Fukui Hiroshi Okada Noriyoshi Kumazawa Yashimi Watanabe 《Metallurgical and Materials Transactions A》2000,31(10):2627-2636
A possibility to make near-net-shape functionally graded material (FGM) products has been examined. The FGM billets having
a graded volume fraction of Al3Ni in thickness direction were machined from an Al-Al3Ni FGM thick-walled tube manufactured by a vacuum centrifugal method. Billets, which were set in the container for the backward
extruding, were heated to 650 °C to 680 °C, at which temperature the FGM becomes a mixture of molten aluminum eutectic and
solid intermetallics. Then, billets were extruded successfully to FGM cups by a semisolid forming, except at 650 °C. Residual
bulky Al3Ni particles are found at higher temperature. Thus, an optimum operation temperature is found to be around 660 °C, because
bulky Al3Ni particles transform to fine spheroidal or fibrous shape after the forming. The volume fraction of intermetallics at the
bottom region of the cup was condensed more than 60 vol pct in a proper billet setting. 相似文献
132.
Mitsutoshi Okada Tohru Hisamatsu Takayuki Kitamura 《Journal of Thermal Spray Technology》2009,18(1):90-95
A superalloy with a thermal barrier coating (TBC) simulating a gas turbine blade is exposed to a high-temperature environment
to develop a method for predicting the local temperature and Al content in a bond coat (BC). The Al content decreases with
an increase in the test time due to the Al transport induced by the oxidation of the BC and the interdiffusion between the
BC and the substrate. This brings about Al-decreased layer (ADL) at the boundary between the BC and the top coat. The thickness
of the ADL increases in proportion to the square root of the test time, and the temperature dependence of the growth rate
shows an Arrhenius-type behavior. Based on this relation, the local temperature of an in-service blade can be estimated by
measuring the ADL thickness when the operation time is known. The Al content decreases in proportion to the ADL thickness.
The prediction method of the Al content based on the relation is also presented. 相似文献
133.
When the excited triplet states of disperse azo dyes with nitro groups abstract hydrogen to generate hydrazinyl (from azo groups) and nitrosyl hydroxide radicals (from nitro groups), both the radicals as H‐acceptors carry out azo scission, conversion to nitrogen dioxide via disproportionation reactions and self‐decomposition via rearrangement. A kinetic equation was formulated by the sum of these reactions, which describes the initial rates (KPA) of reductive fading. The KPA values were controlled by the rate constants of the reactions of hydrazinyl and nitrosyl hydroxide radicals as H‐acceptors, which were estimated by thermochemical analyses of the reactants, intermediates and end products using the semiempirical molecular orbital PM5 method, and by the concentrations of the reactants: H‐acceptors and H‐donors. The KPA values observed for 12 dyes were explained semi‐quantitatively by multiple routes of reactions depending upon to what extent each radical reaction was thermochemically favoured. 相似文献
134.
DS Bardenstein C Cheyer N Okada BP Morgan ME Medof 《Canadian Metallurgical Quarterly》1999,40(2):519-524
PURPOSE: Cell surface complement regulatory proteins have been identified in high levels in ocular tissues, but no experimental model is available for examining their physiological roles. To develop such a model, the distribution of 5I2 antigen, a protein possessing the functions of the human decay-accelerating factor (DAF [CD55]) and membrane cofactor protein (MCP [CD46]), and rat inhibitory protein (CD59), the homologue of the human membrane inhibitor of reactive lysis (MIRL[CD59]) were characterized in the rat eye and ocular adnexal structures. METHODS: After euthanasia of female Wistar rats, followed by orbital exenteration, eyelids and orbital tissue including the lacrimal gland were separated from the globes and immediately snap-frozen in liquid nitrogen at -70 degrees C. Tissues then were sectioned at -20 degrees C and examined immunohistochemically for 5I2 antigen and rat CD59. RESULTS: Both molecules were found to be present in high levels in multiple sites. Corneal and conjunctival epithelia showed moderate to intense labeling for both regulators. Fibroblasts in the corneal stroma, conjunctiva, and sclera labeled similarly. Corneal endothelial cells showed intense labeling for rat CD59 but not for 5I2 antigen. The iris and ciliary body showed intense labeling for both proteins. The retina showed labeling at multiple levels, with that of rat CD59 being more intense than that of 5I2 antigen. The lacrimal gland labeled for both regulators. Vessels, muscle, and nerves in the orbit labeled intensely for both antigens. In the eyelid, conjunctiva, sebaceous glands, and muscle and nerve tissues labeled moderately to intensely for both molecules, whereas skin epithelium labeled less intensely. CONCLUSIONS: 5I2 antigen and rat CD59 are expressed in high levels and distributed similarly in the rat eye and lacrimal gland to DAF, MCP, and MIRL in the human eye and lacrimal gland. These findings establish the rat ocular surface as a model for studying the role of cell surface complement regulators in this site. This first identification of copious expression of these proteins in eyelid structures, which also participate in protection of the ocular surface, further suggests an important role for surface complement regulatory proteins in this location. 相似文献
135.
Takami Kai Norihide Okada Manabu Baba Takeshige Takahashi Masaki Misawa Ion Tiseanu Naoki Ichikawa 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2007,130(2-3):119-124
In a fluidized catalyst bed, the reactant gas transfers from the bubble phase to the emulsion phase and reactions proceed in the emulsion phase. The catalyst particles around the bubbles should contact the gases containing a high concentration of the reactants. Therefore, the effect of the catalysts around the bubbles is very important for estimating the conversion and selectivity in the reactor. In order to study the role of these catalysts, the hydrogenation of carbon dioxide was carried out in a fluidized catalyst bed. Based on the results, the amount of the catalyst that was effective for the reaction was calculated. In addition, the shape of the bubbles ascending in the fluidized catalyst bed was observed using a fast X-ray computer tomography (CT) scanner. The structure of the bubbles in the fluidized catalyst bed was very complicated and the surface area of the bubbles was much greater than the obtained when assuming spherical shaped bubble. By assuming that effective catalysts existed around the bubbles, the thickness of catalyst layer was obtained. Finally, the 3-dimensional images of the catalyst layers around the bubbles were reconstructed. 相似文献
136.
Inthisdecade,agreatmanyresearchworksonmulti-layeredmopeticthinfilmshavebeenreport6d,sincethemagneticmulti-layeredfilmsarethemosthopefulnovelmagneticmaterialsforthenextgenerationelectionicdevises,suchasgialmagneto-resiSbocesensorelemeds.hiordertOdevel... 相似文献
137.
The present authors pointed out in the previous paper [1] that the implicit SMAC scheme is quite efficient and non-staggered grid arrangement can decrease the computational effort and save the storage memory which is very important to the direct numerical simulation (DNS) of complicated 3-D flow fields. But using non-staggered grid arrangement, the pressure field oscillation (PFO) ordinarily occurs and also, the pressure on the solid walls including sharp corners need to be prescribed directly as the pressure boundary conditions.
In this paper, a new interpolation method, which is a modification to Cheng and Armfield's interpolation formulation, is presented in order to completely prevent PFO from occurring, Moreover, a more accurate specification method of wall pressures and special treatment of pressures at sharp corners are proposed. To test the new methods proposed, the DNS of flow past a square cylinder and flows over backward-facing steps, which are typical of the flow fields with sharp corners, is made using the implicit SMAC scheme combined with these methods. The calculated results are compared with the previous experimental and numerical data and show good agreement with them. 相似文献
In this paper, a new interpolation method, which is a modification to Cheng and Armfield's interpolation formulation, is presented in order to completely prevent PFO from occurring, Moreover, a more accurate specification method of wall pressures and special treatment of pressures at sharp corners are proposed. To test the new methods proposed, the DNS of flow past a square cylinder and flows over backward-facing steps, which are typical of the flow fields with sharp corners, is made using the implicit SMAC scheme combined with these methods. The calculated results are compared with the previous experimental and numerical data and show good agreement with them. 相似文献
138.
LiMxMn2−xO4 (M=Co, Ni) materials have been synthesized by a melt-impregnation method using γ-MnOOH as the manganese source. Highly crystallized LiMxMn2−xO4 compounds were synthesized at a calcination temperature of 800°C for 24 h in air. All compounds show a single phase except for LiNi0.5Mn1.5O4 based on the X-ray diffraction (XRD) diagram. With the increase of the doping content from 0.1 to 0.5, the capacity of doping materials decreases mainly in the 4 V region.
Although LiM0.5Mn1.5O4 (M=Co, Ni) compound shows a small capacity in the (3+4) V region compared with parent LiMn2O4, it is a very effective material in reducing capacity loss in the 3 V region that is caused by the Jahn–Teller distortion. The doping of Co and Ni ions in the LiMn2O4 cathode material promotes the stability of this structure and provides an excellent cyclability. 相似文献
139.
Wataru Sugiyama Tomoo Yamamura Ki Chul Park Hiroshi Tomiyasu Yoshinobu Shiokawa Hidetsugu Okada Yuji Sugita 《Progress in Nuclear Energy》2005,47(1-4):448-453
Disposition of low-level radioactive wastes has been performed in supercritical water with RuO2 as a catalyst without the addition of any oxidizing materials. These wastes arose from nuclear power plants etc., constituting of nonflammable organic materials, such as fire resistant sheeting and rubber gloves. We investigated the distribution behavior of iron and cobalt attached to nonflammable organic materials, in solid, liquid and gas phases during the decomposition of this method. The distributions of these elements under various conditions (initial amounts) were determined by using their radioisotopes as simulated low-level radioactive wastes in order to ease the detection of trace amounts of elements even in solid and gas phases. Iron and cobalt were found only in the solid phase when non-radioactive iron hydroxide was added as a precipitation reagent before the supercritical-water reaction. 相似文献
140.
Synthesis of MgO/ZnO hetero-epitaxial whiskers using chemical vapor deposition operated under atmospheric pressure 总被引:2,自引:0,他引:2
A chemical-vapor-deposition (CVD) technique operated under atmospheric pressure is available to synthesize metal oxide crystals with various morphologies. This CVD technique provides highly supersaturating conditions that induce morphological instability of growing crystallites. In this study, the metal oxide material with rock salt structure was selected to confirm the possibility of whisker growth of the cubic system crystal. The MgO whiskers grew epitaxially on the single crystalline substrate of (0001) sapphire under appropriate conditions. The MgO whiskers were also formed epitaxially on the top of the ZnO whiskers. The unique whisker with the MgO/ZnO hetero-junction was successfully obtained. 相似文献