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101.
分析冷氨泵低速运行时打量突然下降的主要原因是由于泵打量过低,不足以将热量带走,液氨在泵的某一级或几级入口过热汽化造成的。根据机组已知的设计参数计算实际工况下冷氨泵在2608r/min转速运转时,为保证泵内液氨不汽化,散热所需的最小流量为13.54m^3/h。 相似文献
102.
Well productivity is a crucial concern in predicting the performance of many gas condensate reservoirs. Accurate forecasting of gas-condensate well productivity usually requires fine-grid simulation to model the formation of the liquid bank and to account for high-velocity phenomena and changes in relative permeability at high capillary numbers. At early stages of production, the pressure drop in the near-wellbore region builds up the molar content of water in gas. This, in turn, results in water vaporization, and hence a drop in the connate water saturation. When water vaporization occurs, pores that were formerly filled by connate water now becomes occupied by gas and condensate only. This causes a change in gas and condensate saturations near the wellbore that can affect the well productivity. No lucid numerical simulation approach considering this effect is suggested in the literature. The authors investigated the effects of water vaporization on the near-wellbore region by compositional simulator of GEM. Enhancement of gas well productivity is observed. 相似文献
103.
液体纯物质的粘度及扩散系数与蒸发潜热间的关系 总被引:1,自引:0,他引:1
刘洪勤 《高校化学工程学报》1993,7(1):1-7
本文结合流体的普遍化范德华理论和粘度与扩散系数的自由体积模型,导出了纯物质的液体粘度及分子扩散系数与蒸发潜热间的关系式。对30种纯物质的粘度与蒸发潜热间的关联误差为1.45%;对20种物质的自扩散系数与蒸发潜热间的关联误差为2.9%。所选物系包括强极性、弱极性和非极性分子。本工作为建立传递性质与平衡性质间的关系,以及提出粘度及扩散系数与温度间的新关联式打下了初步基础。 相似文献
104.
M. F. Butman A. A. Smirnov L. S. Kudin Z. A. Munir 《Journal of Materials Synthesis and Processing》2000,8(1):55-63
A mass-spectrometric method was used to investigate the kinetics of the vaporization of potassium bromide single crystals. In electron-impact-ionization mass spectra of molecular fluxes vaporized from a free-surface of KBr, ions of K+, KBr+, Br+, and K2Br+ originating from KBr and K2Br2 molecular precursors were detected in the temperature range 724–918 K. The temperature dependencies of ion currents, ln IiT – 1/ T, of the most abundant ions (K+, KBr+, and K2Br+) revealed a departure from the linearity. From a comparison between the equilibrium and nonequilibrium vaporization rates, it was concluded that the value of the vaporization coefficient for monomers and dimers passes through a maximum at about 800 and 825 K, respectively. An electron-impact-fragmentation pattern of KBr molecules, I(K+)/I(KBr+), was observed to pass reproducibly through a minimum at the temperatures of about 800 to 830 K. In the fluxes from a free surface and from one inside a Knudsen cell, the dimer-to-monomer ratios were found to vary with temperature in different ways. The difference in the equilibrium and nonequilibrium rates of vaporization, the temperature dependence of the fragmentation pattern, and the mechanism of association reactions are discussed in light of the terrace-ledge-kink and surface-charge models. 相似文献
105.
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108.
Peter Biedenkopf Thomas Karwath Dietmar Kobertz Manisha Rane Egbert Wessel Klaus Hilpert Lorenz Singheiser 《Journal of the American Ceramic Society》2001,84(7):1445-1452
The corrosion and vaporization behavior of eight commercial refractories containing Cr2 O3 were investigated under simulated pressurized pulverized coal combustion (PPCC) conditions at 1723 K in the presence of liquid slag. The corrosion resistance of the refractory materials decreased with increased content of free Cr2 O3 , because bursting (reaction of Fe3 O4 with Cr2 O3 ) occurred. Refractories containing MgCr2 O4 with dissolved Al2 O3 showed the highest corrosion resistance. Thermodynamic calculations showed that CrO3 and CrO2 (OH)2 were the most volatile species in air and in PPCC flue gas, whereas additions of A2 O (A = Na and K, minor slag component) increased the chromium vaporization significantly because of A2 CrO4 formation. Knudsen effusion mass spectrometry measurements showed that the chromium vaporization of refractories was directly correlated to the Cr2 O3 content of the material. In contrast, refractories containing MgCr2 O4 showed a significant decrease in chromium vaporization. 相似文献
109.
全固态钠离子电池由于安全性和元素丰度等天然优势, 在大规模储能领域具有巨大的应用潜力。 全固态电
池的核心是固态电解质, NASICON 型的 Na3Zr2Si2PO12(NZSP) 电解质因为离子电导率高、 热稳定性与力学性能优
异等优点而受到广泛关注。 本研究采用大气等离子喷涂沉积单个 NZSP 扁平粒子和沉积体, 系统研究了粉末粒度
分布和喷涂参数对 NZSP 粒子元素蒸发和沉积体组织结构的影响。 通过沉积单个粒子, 揭示了等离子喷涂参数对
NZSP 粉末粒子的熔化程度和 Na、 P 元素优先蒸发的影响规律。 结果表明, 等离子电弧功率与氢气流量对其蒸发
影响显著, 元素蒸发损失量存在明显的粒子尺寸效应, 粒径小于约 35 μm 时, 随粒径的减小, Na 与 P 的蒸发损
失量显著增加, 当粒径增加至 35 μm 以上时, Na 与 P 的蒸发损失量受粒径的影响显著减小且整体损失量也有限;
通过对粒径范围的控制能够将等离子喷涂过程中 Na 元素的损失量控制在 10 % 以下, P 元素损失量控制在 20 %
以下。 采用粒径范围 30~50 μm 的 NZSP 粉末, 结合大气等离子喷涂参数控制可以得到无明显层状结构的良好层
间结合的组织结构致密电解质, 表明大气等离子喷涂在全固态钠离子电池固态电解质的制备中具有广阔的应用前
景。 相似文献
110.
Physico-chemical properties of ethanol and aqueous solutions of ethanol are important for chemical engineering calculation, modelling and evaluation of processes during ethanol production and its use for food and non-food applications. The majority of these properties are possible to find in handbooks and tables as Yaws (1999): Chemical Properties Handbook; Miller and Yaws (1976): Correlation constants for liquids; Lide (2007–2008): CRC Handbook of Chemistry and Physics; Hole?ek (2007): Chemical-engineering tables; Critical Data Tables and other literature. Some of them are also accessible online. The goal of this paper is to present the formulas and developed algorithms for calculation of extended properties of ethanol collected from literature. Extended properties include density, vapor pressure, surface tension, viscosity, molar and specific heat capacity, enthalpy of vaporization, thermal conductivity and static relative permittivity (dielectric constant) of ethanol. 相似文献