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61.
Tomoyuki Inui 《Catalysis Today》1999,51(3-4):361-368
Recent advances in catalysis for solving the energy and environmental problems are summarized. For these purposes, rapid conversion and selective reaction even under conditions deviating extremely from reaction stoichiometry must be indispensable requisites. In order to realize these requisites, changes in the state of catalyst surface during the reaction were studied, and the catalyst structures on which the optimum reaction performance occurs were determined. An ultra-rapid reforming of methane to syngas with a space–time yield (STY) of 25 000 mol/l h was achieved by using a Rh-modified Ni–Ce2O3–Pt catalyst in which the Rh played the role of portholes for hydrogen spillover and prevents coke deposition on the catalyst surface. As a result, a stable state of the catalyst and the high reaction rate were exhibited. A new catalyst composed of Cu–Zn–Cr–Al–Ga oxides modified with supported Pd exerted a high activity with a high STY of methanol, 6700 g/l h. The catalyst components, Pd and Ga, controlled the reduction state of the catalyst surface by their role on normal and inverse spillover of hydrogen, respectively. The methanol thus produced was then totally converted selectively on a metallosilicate catalyst containing Ga or Fe into an aromatics-lean gasoline using an STY of 1860 g/l h. Finally, non-linear reaction mechanism is used to explain the elimination of NO on metallosilicate catalysts under O2-excess conditions. 相似文献
62.
63.
Takuji Harada Hirotatsu Watanabe Yoshiyuki Suzuki Haruyuki Kamata Yohsuke Matsushita Hideyuki Aoki Takatoshi Miura 《International Journal of Heat and Mass Transfer》2011,54(1-3):649-655
Numerical simulations of combined natural convection–conduction in a droplet of n-dodecane suspended from a thermocouple were carried out, taking into consideration evaporation, and the effect of thermocouple diameter on the evaporation characteristics was investigated. The calculated temperature history of the droplet is in good agreement with experimental results; both show that the rate of heating decreases with increasing thermocouple diameter. The maximum error in temperature due to the thermocouple increases linearly with increasing thermocouple diameter. Thus, in investigations involving a droplet suspended from a thermocouple, it is preferable to use a thermocouple with the smallest possible diameter. 相似文献
64.
For several decades it has been possible to observe a tendency to light structures, particularly when they are destined to develop power and movement by consuming energy, especially when this energy derives from conventional fuel (petroleum derivates). Lighter means of transport permit savings on fuel consumption and contribute to the environmental protection due to the reduction of greenhouse gases. The first approach in this direction had been the utilization of innovative materials able to offer further improved mechanical strength. Nevertheless, this way presents natural limits depending on the loss of rigidity, hence excessive deformability even in the elastic field. This fact leads to the necessity to add stiffeners and reinforcing elements, but this at the same time means increase again the heaviness. Under these conditions more complex structural solutions step forward as the ‘sandwich’-structures manufacturable in a modular way provided with remarkable versatility in terms of design and choice of material. In the 1990s a European research project named ‘Sandwich’ financed by the European Union had given a significant contribution to the industrialization of structural solutions, which present a high level of innovations using aforementioned structures. The present work proposes a preliminary study and several results of an investigation, which has as the main subject the production of innovative structural sandwich panels, in other words hybrid-sandwich panels in steel-aluminium assembled using two different joining technologies as laser and FSW, which can successively be connected as well to steel structures as to aluminium ones. 相似文献
65.
Kiyoshi Yoshida Kaname Kizu Haruyuki Murakami Koji Kamiya Atsushi Honda Yoshihiro Ohnishi Masato Furukawa Shuji Asakawa Masaya Kuramochi Kenichi Kurihara 《Fusion Engineering and Design》2013,88(9-10):1499-1504
The modifying of the JT-60U magnet system to the superconducting coils is progressing as a satellite facility for ITER by both parties of Japanese government and European commission in the Broader Approach agreement. The magnet system requires current supplies of 25.7 kA for 18 TF coils and of 20 kA for 4 CS modules and 6 EF coils. The magnet system generates an average heat load of 3.2 kW at 4 K to the cryogenic system. The feeder components connected to the power supply provide current supply. The cooling pipes connected to the cryogenic system provide coolant supply. The instrumentation of the JT-60SA magnet system is used for its operation. 相似文献
66.
Toru Inui Chris Chau Kenichi Soga Duncan Nicolson Nick O’Riordan 《Canadian Metallurgical Quarterly》2011,137(10):958-967
The embodied energy (EE) and gas emissions of four design alternatives for an embankment retaining wall system are analyzed for a hypothetical highway construction project. The airborne emissions considered are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulphur oxides (SOX), and nitrogen oxides (NOX). The process stages considered in this study are the initial materials production, transportation of construction machineries and materials, machinery operation during installation, and machinery depreciations. The objectives are (1)?to determine whether there are statistically significant differences among the structural alternatives; (2)?to understand the relative proportions of impacts for the process stages within each design; (3)?to contextualize the impacts to other aspects in life by comparing the computed EE values to household energy consumption and car emission values; and (4)?to examine the validity of the adopted EE as an environmental impact indicator through comparison with the amount of gas emissions. For the project considered in this study, the calculated results indicate that propped steel sheet pile wall and minipile wall systems have less embodied energy and gas emissions than cantilever steel tubular wall and secant concrete pile wall systems. The difference in CO2 emission for the retaining wall of 100?m length between the most and least environmentally preferable wall design is equivalent to an average 2.0?L family car being driven for 6.2?million miles (or 62 cars with a mileage of 10,000??miles/year for 10?years). The impacts in construction are generally notable and careful consideration and optimization of designs will reduce such impacts. The use of recycled steel or steel pile as reinforcement bar is effective in reducing the environmental impact. The embodied energy value of a given design is correlated to the amount of gas emissions. 相似文献
67.
Kyosuke Kishida Akira Ishida Tatsuya Koyama Shunta Harada Norihiko L. Okamoto Katsushi Tanaka Haruyuki Inui 《Acta Materialia》2009,57(6):2010-2019
The thermoelectric properties of ternary and Al-containing quaternary Ru1?xRexSiy chimney–ladder phases have been studied as a function of the Re concentration with the use of directionally solidified alloys. The Ru1?xRexSiy chimney–ladder phases exhibit n- and p-type semiconducting behaviors, respectively, at low and high Re concentrations, at which the X(=Si)/M(=Ru + Re) ratios are respectively, larger and smaller than those expected from the VEC (valence electron concentration) = 14 rule. The absolute values of both Seebeck coefficient and electrical resistivity increase as the extent of the deviation from the VEC = 14 rule increases, i.e. as the alloy composition deviates from that corresponding to the p–n transition (x ≈ 0.5), indicating that the carrier concentration can be controlled by changing the extent of compositional deviation from the ideal VEC = 14 composition. The highest values of the dimensionless figure of merit obtained are 0.47 for ternary (x = 0.60) and 0.56 for Al-containing quaternary alloys. The reasons for the systematic compositional deviation from the ideal VEC = 14 compositions observed for a series of chimney–ladder phases are discussed in terms of atomic packing. 相似文献
68.
Porous Titania Ceramic Prepared by Mimicking Silicified Wood 总被引:6,自引:0,他引:6
Toshitaka Ota Masaki Imaeda Haruyuki Takase Mikihiro Kobayashi Noboru Kinoshita Tunehisa Hirashita Hidetoshi Miyazaki Yasuo Hikichi 《Journal of the American Ceramic Society》2000,83(6):1521-1523
A porous titania ceramic with a woodlike microstructure that was analogous to silicified wood was prepared. The production of "titanified wood" was performed using the following process: (i) introduction of titanium tetraisopropoxide into wood materials via vacuum infiltration, (ii) hydrolysis of the titanium tetraisopropoxide in the cell structure to form a titania gel, and (iii) firing at a temperature of 600°–1400°C in air. The resulting titania ceramic had the same external and internal forms of the original wood. 相似文献
69.
MFI-type metallosilicates incorporating various transition metal elements were synthesized by the rapid crystallization method. Compared with H-ZSM-5, these metallosilicates possess fewer acid sites and weaker acidic strength. In the methylation of toluene with methanol, protonated metallosilicates exhibited lower conversion of toluene, higher para-selectivity and higher yield of paraxylene than H-ZSM-5. Distributions of trimethylbenzene and tetramethylbenzene isomers produced in toluene methylation indicate that the effective pore size (openings and/or channels) of metallosilicates may be smaller than that of ZSM-5, which is more advantageous for formation of the smallest isomers in trimethylbenzenes and tetramethylbenzenes. The relation between the paraselectivity in toluene methylation and the isomerization activity in para-xylene conversion suggests that the para-selectivity could occur exclusively, when isomerization of para-xylene to other isomers could be completely prevented. Therefore, the improvement in para-selectivity on MFI-type metallosilicates should be attributed to both the reduction in effective pore size and the decrease of strong acid sites, on which produced para-xylene would be isomerized to ortho- and meta-xylenes. 相似文献
70.