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排序方式: 共有525条查询结果,搜索用时 187 毫秒
21.
LE2000智能射频物位计对液位的测量具有较高的可靠性、稳定性和准确性。简要介绍了LE2000智能射频物位计系统及其在炼钢转炉汽化系统的应用。 相似文献
22.
Michael V. Mundschau David A. Gribble Jr. Paul N. Plassmeyer Lee M. Henton Nicholas R. Jentzsch 《Fuel》2010,89(6):1202-457
Volatile compounds distilled below 205 °C from diesel fuel are reformed into synthesis gas by dry catalytic partial oxidation using porous membrane reactors, eliminating complex liquid-fuel injectors and fuel-air mixers, greatly simplifying reformers for applications with solid-oxide fuel cells and NOx traps. For distillates utilizing 20 wt% of the diesel fuel, 88 mol% of the carbon is converted into CO and 75 mol% of the hydrogen into H2. Rationale is as follows: Long-chain n-alkanes such as n-hexadecane, with normal boiling point, 286.5 °C, but autoignition temperature, 205 °C, are the least thermally stable hydrocarbons in diesel fuel. If attempts are made to vaporize diesel fuel under oxygen-lean conditions without precautions, long-chain n-alkanes crack at autoignition temperatures forming radicals that initiate polymerization. By eliminating more troublesome compounds by distillation, and by effusing cooler air through porous ceramic membranes to react radicals with oxygen, carbon deposition is largely suppressed. A perovskite catalyst, fed pre-heated air at >900 °C, provides a reservoir of mobile lattice oxygen to react with adsorbed carbon. In continuous runs of 72 h, carbon deposition was negligible in the reactor, on the catalyst, and in the exhaust, except for minor graphite deposited onto walls near the catalytic hot zone. 相似文献
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煤粉燃烧过程中矿物质气化影响因素的模拟研究 总被引:5,自引:5,他引:5
鉴于目前国内的实验设备和测量手段,精确测量煤燃烧过程中各种矿物质的气化率还存在很大困难。该文通过建立煤中矿物质气化的数学模型,针对煤中SiO2和FeO两种成分,来探讨相关因素对它们气化率的影响,最后应用CFD软件来研究它们在600MW锅炉内的气化行为。计算结果表明:温度是煤中SiO2和FeO气化的主要影响因素,煤粒粒径和CO2浓度也会对它们有一定影响。通过与实验结果的比较,表明计算结果比较合理。 相似文献
25.
对气蚀和闪蒸的定义、产生的条件进行了详细论述,以规范不同版本书籍在概念上的模糊不清,以及 由此造成的调节闯流量系数计算的复杂性和对调节阀的损害,以便采取相应措施,在实际工况条件下加以避免. 相似文献
26.
刘智勇 《河北工业大学学报》1992,(1)
本文提出了一个由液体比容和正常沸点下汽化热数据推算物质临界参数的新方法.采用本文方法对有代表性的近100种有机物的 P_c 和 T_c 值进行了估算.计算结果表明,本文方法稳定、可靠. 相似文献
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介绍了真空汽化冷凝技术制备纳米级材料实验的原理和过程,用真空汽化冷凝技术制备纳米块状锌,并用扫描电镜观察纳米锌的形貌、晶粒度,用X射线衍射测定真空汽化冷凝钠米锌的生长方式及择优取向,用显微硬度计测定了合金锌、粉状锌以及纳米锌的显微硬度,并对此进行了分析。 相似文献
29.
Duane L. DeBastiani Michael F. Modest Vladimir S. Stubican 《Journal of the American Ceramic Society》1990,73(7):1947-1952
The mechanism of material removal from SiC by CO2 laser heating was studied using sintered and single-crystal α-SiC. Removal rate and width of the groove showed maxima when plotted as a function of translation speeds. Groove depth decreased as the translation speed of samples increased. Similar results were obtained if argon or air was used as gas assist, which indicated that the material removal mechanism is induced dissociation of SiC. Microstructure of the material deposited in and outside of the groove was studied by SEM. At low scanning speeds, columnar grains 10 to 50 μm long appeared. As the scanning speed increased, columnar grains became smaller and finally only irregular polycrystalline particles were observed. By using Raman spectroscopy, Auger analysis, and X-ray diffraction, phases inside and outside the groove were identified as Si, β-SiC, C, and SiO2 . Columnar grains were identified as β-SiC covered with thin layers of C, Si, and SiO2 . Slow scanning speeds enhanced the growth of β-SiC. At slow scanning speed, free silicon was always found in the grooves of lased single crystals but not in the grooves of lased sintered SiC. It can be concluded that the mechanism of material removal from silicon carbide by CO2 laser heating is a vaporization process, and material found in the groove and on the surface near the groove is formed by condensation from the vapor. 相似文献
30.
Vapour pressure measurements are used to evaluate the enthalpy of vaporization of ethanol-gasoline mixtures. Partial molar values are also derived. The dispersed structure of ethanol-gasoline fuel is studied for the first time using the method of correlation spectroscopy of scattered light. A large range of dispersed particle sizes in different alcohol-gasoline systems is found. The dependence of the mean radius of drops on ethanol content is determined. It is found that coalescence phenomenon occurs in the systems when extra ethanol is added. 相似文献