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41.
高铁闪锌矿的成分较为复杂,形成焙砂矿中氧化物的存在形态也较多。将锌精矿高温氧化焙烧产物进行多次综合取样,分析高铁高铟闪锌矿焙砂的结构及其物相组成,研究结果表明:生成的焙砂粒度大部分在35~200目之间,占总量的82.27%;焙砂主要由ZnO、ZnFe_2O_4、Zn_2SiO_4、Fe_3O_4组成,各氧化物在焙砂中所占的比例会随着颗粒大小的变化而有所不同。焙砂200~300目中ZnO的含量最高,同时存在少量的ZnFe_2O_4及铁的氧化物,在35~200目中铁的氧化物分布较广泛,在大于35目的焙砂中Zn_2SiO_4分布较广泛。 相似文献
42.
Intergranular corrosion behavior of the 7075-T6 aluminum alloy under different annealing conditions 总被引:1,自引:0,他引:1
The effect of annealing conditions producing various grain sizes on the intergranular corrosion behavior of high-strength aluminum alloy type 7075-T6 was investigated using electrochemical polarization techniques. Aluminum alloy specimens with large grain size exhibited lower breakdown potentials in deaerated 0.5 M NaCl solution. The breakdown potentials decreased with increasing grain size. Microscopic observations of the exposed surfaces during potentiostatic polarization testing showed that the coarse grain structure promotes intergranular crack growth. 相似文献
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Jonna Holmgren Jannica Heinrichs Lindgren Åsa Kassman Rudolphi Staffan Jacobson 《应用聚合物科学杂志》2024,141(9):e55027
Polymers and polymer composites are frequently used in tribological applications. However, their use is often limited by excessive wear or plastic deformation, therefore research and development aiming to improve the materials is ongoing. Tribological evaluations of polymer composites often study the friction coefficient and wear rate for different types, sizes and amounts of fillers. But rarely are any mechanisms presented. Although polymer materials differ from metals, the techniques typically used for metal components, for example, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), can be adapted to polymer materials, to achieve more informative SEM micrographs and EDS analyses. The aim of this article is to present useful analysis strategies, from sample preparation and selection of viewing angles, to selection of instrument settings and detector types. The strategies are exemplified by analysis of poly-phenylene-sulphide filled with glass fiber, evaluated against steel in a reciprocating ball-on-flat test set-up. This article takes its starting point with the worn surfaces, and subsequently analyze them using SEM and EDS. A selection of cross section preparation techniques, analysis parameters and microscopy settings are presented and discussed. By combining these techniques and settings, the observation of a strongly modified surface layer, as well as sub-surface plastic deformation and imbedded wear particles, is facilitated. 相似文献
46.
A levitation method has been introduced which uses 8-shape levitation coils arranged on the vertical surface of the guideway. These coils can act as a guidance means as well as the levitation means. The characteristics of this system are examined using numerical examples and experimental data. The cables connecting right and left coils are not connected to a high-voltage power source unlike the usual guidance system which is combined with propulsion. Thus the electric insulation of the cables is not a problem at present. Numerical examples show that the levitation characteristics of the combined levitation and guidance system are almost the same as in the system without the guidance function, and that it attains reduced running resistance with necessary guidance stiffness obtained. A test run was done at Miyazaki Test Line equipped with coils of this type arranged about 120 m, and the results show stable running and balanced displacement which agrees with calculated values. 相似文献
47.
Lalit Kumar R. Venkataramani M. Sundararaman P. Mukhopadhyay S. P. Garg 《Oxidation of Metals》1996,45(1-2):221-244
The oxidation behavior of Inconel 625 during the early stages (<150 min) has been studied at oxygen pressures (PO
2) of 0.12 kPa (0.9 torr) and 101.3 kPa (760 torr) in the temperature range of 1323 K to 1523 K by using TGA and between 873 and 1523 K by using XPS, AES, and EDS. The TGA results correlated well with those obtained by surface analysis of the oxide films. The results of XPS and AES analysis suggested that two distinctly different oxidation mechanisms operate, depending on the temperature of oxidation. Enrichment of the oxide films with respect to Cr2O3 occurs above 873 K, the degree of enrichment peaking at about 1200 K such that the oxide films formed at temperatures close to this consist almost exclusively of Cr2O3. At temperatures above 1300 K, the oxides of two minor alloying components, Nb and Ti, have been found to be present in the oxide films in significant proportions. The results have been discussed on the basis of the relative thermodynamic stabilities of the competing oxide phases and the diffusivities of the alloying elements in Inconel 625. 相似文献
48.
A new diffusion-multiple technique was used for mapping the phase diagram in the pseudo-quaternary Fe3Al-Cr-Mo-C system at 800 °C. The following five carbide phases were formed in an Fe3Al matrix phase (B2) with composition gradients of Cr, Mo, and C in the diffusion-multiple samples: κ-Fe3AlC, M5C, M6C, Cr7C3, and M2C (M: Mo, Cr, Al, and Fe). It was assumed that B2 phase is in equilibrium with κ, M5C, M6C, and Cr7C3 but not with M2C phase at 800 °C. Complex phase equilibria among those phases were efficiently mapped by the diffusion-multiple technique.
The results from the technique were consistent with those obtained from the conventional bulk alloy method. 相似文献
49.
The concentrations of 30 elements in aerosol particles collected in western Pacific ocean have been determined by INAA. The crustal element concentrations decrease with increasing distance from land over the remote area close to Asia land and fluctuate around its average value over the remote ocean area. The volatile elements exhibite average atmospheric concentrations that are higher than those expected from the flux of seasalt or the continental dust. In order to identify marine aerosol component originating from the continent or ocean, the aerosol particles are examined by scanning electron microscopy combined with energy dispersive X-ray spectroscopy. Particle phase structure shows that the crustal aerosol particles are not present internal mixtures with seasalt aerosol, and it also proves the long-range transport of crustal elements from continent to ocean. 相似文献
50.
In this work, undoped and Zn-doped copper oxide films were deposited on glass substrates at a substrate temperature of 250 ± 5°C
by using an ultrasonic spray pyrolysis technique. Electrical, optical, and structural properties of the films were investigated,
and the effect of Zn incorporation on these properties are presented. The variations of electrical conductivities and electrical
conduction mechanisms of all films were investigated in the dark and in the light. Optical properties of the produced films
were analyzed by transmission, linear absorption coefficient, and reflection spectra. The band gaps of the films were determined
by an optical method. The film structures were studied by x-ray diffraction. To obtain information about structural properties
in detail, the grain size (D), dislocation density (δ), and lattice parameters for preferential orientations were calculated. The elemental analyses were performed using energy-dispersive
x-ray spectroscopy. It was concluded that Zn has a strong effect, especially on the electrical and structural properties,
and the undoped and Zn-doped copper oxide (at 3%) films may be used as absorbing layers in solar cells due to their low resistivities
and suitable linear absorption coefficient values. 相似文献