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121.
AD Spiegel 《Canadian Metallurgical Quarterly》1998,23(5):383-405
Shortly after President Abraham Lincoln's assassin was killed on April 26, 1865, a formal inquest was held to positively identify the body. Dr. John Frederick May, a leading surgeon in the District of Columbia, was summoned to examine the remains. Two years earlier, Dr. May had removed a fibroid tumor from the back of the assassin's neck and an identifiable large ugly scar resulted when the wound inadvertently opened and healed by granulation. Based upon the recognition of the scar made by his scalpel, Dr. May made a positive identification. 相似文献
122.
Composite polymeric electrolytes (CPE) are well known systems in which an improvement in electrical conductivity of the polymer is achieved by the addition of a non-conductive additive (ceramic powders and immiscible polymers). A new class of conductivity models based on the application of the multi-value random resistor networks to the studies of CPE was developed by the authors. The first stage of the simulation is based on the virtual composite sample generation and its transformation into a form of the three-dimensional resistor network. The sample generation can take into account variable material parameters such as average grain diameter, shell thickness as well as their statistical distribution and different dependencies of local shell conductivity on the distance from the grain surface. The second stage of the algorithm is the use of the modified iteration procedure based on Kirkpatrick approach leading to the direct current resistivity of the virtual sample. The presented results were obtained for the matrix size 100 unit × 100 unit × 100 unit (with assumption 1 unit = 1 μm). The dependency of conductivity on the grain filler concentration was studied for varying grain sizes, changing shell thickness as well as for different statistical distributions of these parameters. The obtained results of simulation are in general agreement with the experimental data. 相似文献
123.
iTVP is a system built for delivery of live TV programming, video-on-demand and audio-on-demand with interactive access over IP networks. It has a nationwide range and is designed to provide service to a high number of concurrent users. Hence, scalability is one of the most important issues. In this paper we described how scalability is achieved in a two-level hierarchical architecture of the delivery system. We present the principles of content caching mechanisms and the management of the resulting distributed content repository. The system is implemented and currently operates in a test installation. Although the range of the test system operations is limited, as far as the number of users and the size of the content repository is concerned, the experience gained with iTVP so far provides an insight into the expected prototype performance. We present a system performance evaluation and describe the experience gained during the iGrid demonstration. 相似文献
124.
Maciej Drozd Peter Husar Antoni Nowakowski Guenter Henning 《IEEE engineering in medicine and biology magazine》2005,24(1):51-58
In the functional diagnostics of human sensor systems, the analysis of stimulus responses embedded in an electroencephalogram (EEG), e.g. evoked potentials (EPs), is of high relevance for an objective electrophysiological assessment. The aim of this work is to detect weak EPs from highly contaminated signal traces. In principle this can be done using methods of spatiotemporal signal processing, which simultaneously increase the weak SNR (signal-to-noise ratio). However, methods based on any a priori knowledge of spatial or temporal properties as well as the propagation speed and direction are not applicable. Models with adjustable signal properties similar to real cortical activity are necessary for the development and evaluation of new methods of spatiotemporal signal processing. A model is needed which can be used in forward- and inverse-projection calculations. This study aims to develop a signal generator of the background EEG activity with embedded EPs of fully adjustable signal parameters. The study also compares the results of modeled signal analysis by known methods for signal decomposition, SVD (singular value decomposition) and ICA (independent component analysis). 相似文献
125.
Maciej Pietrzyk Zbigniew Kedzierski Halina Kusiak Wieslaw Madej John G. Lenard 《国际钢铁研究》1993,64(11):549-556
A thermomechanical finite-element model of flat rolling is coupled with closed form equations describing the process of recrystallization and is applied to study hot rolling of low carbon steel strips. Formulae for the recrystallized grain diameters, developed by various authors, are considered. Calculated diameters of the grains are compared with the results of the measurements carried out after experimental hot rolling of the carbon steel samples. Evaluating the accuracy of the calculations, using each of the expressions for the diameter of the recrystallized austenite grains, indicates that the relation of Roberts is closest to the measurements. 相似文献
126.
Maciej Wisniewski Jan Szymanowski Wladyslaw Walkowiak Malgorzata Michalewska 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1992,53(3):243-251
Interfacial tension isotherms were determined in hydrocarbon-water systems for 4-alkylphenylamines containing from 6 to 16 carbon atoms in their alkyl chains, and the surface excess isotherms were computed and interpreted using various adsorption isotherms. Palladium(II) was extracted with 4-alkylphenylamines from 3 M HCI solutions. The maximum extraction rate of palladium(II) is observed for 4-decyl- and 4-dodecylphenylamines which exhibit good interfacial activity. Compounds soluble in the aqueous phase (4-hexylphenylamine) or in toluene (4-hexadecylphenylamine) extract palladium(II) slower than 4-decyl- and 4-dodecyl- phenylamines. 相似文献
127.
This paper focuses on the problem of the evaluation of strains around the inclusions of various shapes and properties located in the uniform matrix undergoing large plastic deformations. The analysis is performed using the rigid-plastic finite-element approach. The uniform plane-strain deformation field is simulated by an introduction of zero friction forces into the program for the compression process. An assumption that the die is wider than the sample allows to simulate ideally uniform flow of metal. Several shapes of the inclusions are investigated, but the results for three most common shapes of the particle's cross-section are presented in the paper. They are: square with the sides parallel to the main directions, square with the sides inclined under an angle of 45° to the main directions and round. 相似文献
128.
Donald Spiegel 《Drug development and industrial pharmacy》1985,11(5):1059-1072
Multiple controls during the manufacture of pharmaceutical products are considered essential for the achievement of consistent high quality in such products. The problem normally associated with manufacturing high quality products are multiplied in the international marketplace. Global scale problems associated with regional jurisdictions and varied control standards will be discussed in detail. 相似文献
129.
The o-anisidine and pyrrole have been polymerized by the electrochemical oxidation of monomers on gold electrodes, covered with self-assembled monolayers. The obtained polymer–monolayer systems have been investigated by cyclic voltammetry in aqueous supporting electrolyte solutions containing K4Fe(CN)6 and Ru(NH3)6Cl3. The deposition of conducting polymers strongly depends on the integrity of a monolayer. In the case of a large number of SAM defects, the polymerization of o-anisidine and pyrrole leads to the formation of nuclei of the conducting polymer in the insulating matrix of the thiol monolayer. When the polymer is in the conducting (oxidized) form, the nuclei act as an array of microelectrodes. The polarogram-shaped voltammograms obtained for K4Fe(CN)6 confirm the hemispherical diffusion of redox species to the polymer nuclei. When the polymer is in the non-conducting (reduced) form, the polymer–octadecanethiol layer blocks the redox processes on the electrode. The exponential-type CV curves observed for Ru(NH3)6Cl3, when the polymer is in its non-conducting state, can be assigned to the tunnelling of electrons through the passivating layer. The use of monolayers with a low number of defects influences the mechanism of polymer growth. Thus, the polypyrrole grows on the layer of thiols, and the poly(o-anisidine) forms polymer nuclei. 相似文献
130.
Several tests of water cooling of steel samples are presented in the paper. The water spray and quenching conditions are considered. The temperature variations during the tests are monitored using the thermocouples embedded in the side of the samples. The experimental time – temperature profiles are compared with the results of calculations based on the finite element model. Comparison of the theoretical and experimental results allowed to suggest heat transfer coefficients of 10000 W/m2K for water in quenching, 6000 W/m2K for the top surface during water spray cooling and 4000 W/m2K for the bottom surface during water spray cooling. 相似文献