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Siegel H.J. Nation W.G. Kruskal C.P. Napolitano L.M. Jr. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1989,77(12):1932-1953
A critical component of any large-scale parallel processing system is the interconnection network that provides a means for communication along the system's processors and memories. Attributes of the multistage cube topology that have made it an effective basis for interconnection networks and the subject of much ongoing research are reviewed. These attributes include O (N log2N ) cost for an N -input/output network, decentralized control, a variety of implementation options, good data-permuting capability to support single-instruction-stream/multiple-data-stream (SIMD) parallelism, good throughput to support multiple-instruction-stream/multiple-data-stream (MIMD) parallelism, and ability to be partitioned into independent subnetworks to support reconfigurable systems. Examples of existing systems that use multistage cube networks are considered. The multistage cube topology can be converted into a single-stage network by associating with each switch in the network a processor (and a memory). Properties of systems that use the multistage cube network in this way are examined 相似文献
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John F. Curry Tomas F. Babuska Timothy A. Furnish Ping Lu David P. Adams Andrew B. Kustas Brendan L. Nation Michael T. Dugger Michael Chandross Blythe G. Clark Brad L. Boyce Christopher A. Schuh Nicolas Argibay 《Advanced materials (Deerfield Beach, Fla.)》2018,30(32)
Recent work suggests that thermally stable nanocrystallinity in metals is achievable in several binary alloys by modifying grain boundary energies via solute segregation. The remarkable thermal stability of these alloys has been demonstrated in recent reports, with many alloys exhibiting negligible grain growth during prolonged exposure to near‐melting temperatures. Pt–Au, a proposed stable alloy consisting of two noble metals, is shown to exhibit extraordinary resistance to wear. Ultralow wear rates, less than a monolayer of material removed per sliding pass, are measured for Pt–Au thin films at a maximum Hertz contact stress of up to 1.1 GPa. This is the first instance of an all‐metallic material exhibiting a specific wear rate on the order of 10?9 mm3 N?1 m?1, comparable to diamond‐like carbon (DLC) and sapphire. Remarkably, the wear rate of sapphire and silicon nitride probes used in wear experiments are either higher or comparable to that of the Pt–Au alloy, despite the substantially higher hardness of the ceramic probe materials. High‐resolution microscopy shows negligible surface microstructural evolution in the wear tracks after 100k sliding passes. Mitigation of fatigue‐driven delamination enables a transition to wear by atomic attrition, a regime previously limited to highly wear‐resistant materials such as DLC. 相似文献
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Using the Levenberg-Marquardt nonlinear optimization algorithm and a series of Lorentzian line shapes, the fluorescence emission spectra from BG (Bacillus globigii) bacteria can be accurately modeled. This method allows data from both laboratory and field sources to model the return signal from biological aerosols using a typical LIF (lidar induced fluorescence) system. The variables found through this procedure match individual fluorescence components within the biological material and therefore have a physically meaningful interpretation. The use of this method also removes the need to calculate phase angles needed in autoregressive all-pole models. 相似文献
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Richard A. Graves Grace Ledet Cedric A. Nation Porscha Renee Showers Yashoda Pramar Tarun Mandal 《Drug development and industrial pharmacy》2015,41(5):819-824
Objective: The goal of this study is to develop an ultra-high performance liquid chromatographic method for the quantitative determination of artemisinin at very low concentrations using selective ion mass spectroscopic detection.Materials and methods: Separation was conducted using a C4 100?mm×?2.1?mm column, and the mobile phase consisted of an isocratic two-component system consisting of 60% of a 0.1% aqueous solution of formic acid and 40% acetonitrile at a flow rate of 0.4?ml/min. The drug was detected by means of an electrospray mass spectrometer with selective ion monitoring of the [M-H2O+H]+ with m/z of 265.3 in positive ion mode.Results: The calibration curves of artemisinin obtained from the UPLC/MS system were linear in the three ranges analyzed, with a correlation coefficient of no less than 0.9996 for all sets of standards. The peak tailing factor for all measurements were ≤1.7. The method proved to have good repeatability and linearity.Discussion: The described analytical method reached a LOQ of 0.010?µg/ml with an isocratic system and enables an analysis rate of 20 samples per hour. The linearity of the standards was excellent for all sets of standards analyzed.Conclusion: The method presented in this study provides a rapid and suitable means for the determination of artemisinin at very low concentrations. This is especially significant when performing dissolution studies where, due to the low solubility of artemisinin, a method that can measure the drug at nanogram levels is necessary. 相似文献
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用已知化学纯度的 16 2 Dy、16 4Dy两种浓缩同位素通过化学计量 ,配制人工合成校准样品 ,测量质谱计系统误差校正系数 K,校正用该仪器测量的来自地球不同地域矿物和试剂样品镝 ( Dy)元素天然同位素丰度比 ,求出自然界 Dy同位素丰度的真值。用该真值和它的核素质量 ,计算 Dy原子量 1 62 .4 995 ( 1 7)。上述测量经 IUPAC国际原子量委员会 ( UPAC-CAWIA)评审确认推荐报告中提供的测量值为 Dy原子量新的国际标准值 ,测量方法评为最佳测量 相似文献
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本文简要介绍了化学测量溯源性和具有绝对测量性质的同位素稀释质谱法(IDMS),并应用该法为国际测量评估计划(IMEP-9)河水样品中的钾提供可直接溯源到SI单位的标准值。 相似文献
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Nigg H. N. Mallory L. L. Simpson S. E. Callaham S. B. Toth J. P. Fraser S. Klim M. Nagy S. Nation J. L. Attaway J. A. 《Journal of chemical ecology》1994,20(3):727-743
Extracts of 22 fruits were tested for their attractancy toAnastrepha suspensa (Loew), the Caribbean fruit fly. Box-orange, calamondin, carambola, cattley guava, loquat, and Surinam-cherry were about equal in attractiveness to males and females. Nine synthetic chemicals, including four found in box-orange ripe seed, were attractive to females. Five synthetic chemicals, including two in box-orange ripe seed, were attractive to males. Farnesol,-phellandrene, and 3-carene were highest in attractiveness to both males and females. Females were more attracted than males to 12 synthetic chemicals. These data suggest that host chemicals serve as attractants and that female and male specific attractants and traps could be developed from host kairomone data. These data also suggest that the volatilization of chemicals from water may play an important role in kairomone biology. 相似文献