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排序方式: 共有434条查询结果,搜索用时 46 毫秒
51.
The perchloroethylene coal desulfurization process has unique advantages as a precombustion coal cleaning process, that include high cleaning efficiencies, mild process conditions, minimal output of undesirable byproducts, and cost effectiveness. However, the use of perchloroethylene in the process renders an important process engineering problem of complete recovery and reuse of perchloroethylene. thus requiring a “zero discharge” condition of the solvent. Therefore, the treated coal must be stripped of any residual perchloroethylene. Carbon dioxide (CO2) in its supercritical state has been investigated for its ability to remove chlorine from Indiana 5 coal, that has been desulfurized by the perchloroethylene (PCE) process. The reduction of CI contenttffrom a PCE treated and filtered coal has been as high as 78% The exprements have been carried out. following a statistical experimental design and the discerning characteristics of the process been identified. The solvent density and extraction conditions can be tailored in such a way as to optimally remove CI from the coal without any detrimental effects on the coal matrix. The supercritical CO2 extraction process can be successfully implemented to the PCE coal cleaning process by replacing energy intensive steps of steam stripping and vacuum dying 相似文献
52.
Fouad A. A. Kruempel K. C. Vittal V. Ghafurian A. Nodehi K. Mitsche J. V. 《Power Systems, IEEE Transactions on》1986,1(1):2-8
The output of a conventional transient stability program is analyzed using transient energy functions for individual machines. The analyst is provided with a quantitative index of the degree of stability or instability for each generator. This index is useful for guiding the selection of subsequent case studies. The transient energy consists of two components: kinetic and potential energy. In the post-disturbance period, profiles of the kinetic energy (VKE), the potential energy (VPE), and the time derivative of the potential energy (V?PE) are obtained. These are used to develop a criterion for the degree of stress on a disturbed but stable machine, and to assess the extent of instability for an unstable machine. The method of analysis has been tested on two power networks representing the system of the state of Iowa, and validated by studies on a Philadelphia Electric Co. network. 相似文献
53.
This paper deals with the investigation of the loss of generation disturbances by the transient energy function (TEF) method. It describes the modeling of the loss of generation disturbance and the post-disturbance conditions. A technique for simulating the out-of-step impedance relay operation following loss of generation is developed and the transient energy margin obtained from the TEF method is related to the out-of-step impedance relay setting. The procedure is applied to two cases of loss of generation in the Florida Power & Light Company network. 相似文献
54.
55.
A. M. Farid S. S. Fouad A. H. Ammar 《Journal of Materials Science: Materials in Electronics》2005,16(2):97-101
High purity glasses with an average coordination number Nc in the GexSb40–xSe60 ternary system between 2.4 and 2.7, were prepared under vacuum with x = 0, 10, 20 and 30. X-ray diffraction (XRD) as, well as the Differential Scanning Calorimetry (DSC) studies were carried out to identify the amorphous and polycrystalline structure for the Ge-Sb-Se system. The dependence of properties such as the mean atomic volume Va, the glass transition temperature Tg and the number of topological constraints Ncon were studied as a function of Nc, in the light of recent model proposed for covalent random network. The occurrence of this dependence in addition to those due to topological effects leads to the conclusion that the effects of chemical ordering and the effect, which have topological origin, coexist in this system. To understand the effect of Nc on the glass-forming capability, the number of lone-pair electrons, (Ncs–Nc)/2, and the efficiency of the structural modification were calculated and discussed in relation to topological consideration. This then renders support to Phillipstheoretical model. 相似文献
56.
M Abd-el-Fattah R Scherer FM Fouad G Ruhenstroth-Bauer 《Canadian Metallurgical Quarterly》1981,41(6):2548-2555
Transplantation of Yoshida sarcoma (solid type) and Zajdela ascites hepatoma tumors in rats induces a biphasic change in the concentration of the following five acute-phase proteins: alpha-1-acid glycoprotein; alpha-1-antitrypsin; haptoglobin; hemopexin; and ceruloplasmin. These proteins and other plasma proteins were quantitated by two-dimensional immunoelectrophoresis relative to normal serum concentrations. The elevation of most of these acute-phase proteins was greater in the second phase, during which serum levels increased continuously as the tumor burden increased until the animals died. The increase in haptoglobin concentration during the second phase was much higher in rats bearing Yoshida sarcoma than in rats bearing Zajdela tumors. Rats receiving irradiated tumor cells showed neither tumor growth nor second-phase protein changes. Significant increases in uptake of 3H-amino acids by isolated perfused livers of tumor-bearing rats provided evidence for an increase in the hepatic synthesis rates of the acute-phase proteins. Removal of the solid tumor resulted in a gradual decrease of acute-phase protein concentrations with concomitant increase in serum albumin concentration. These alterations in serum acute-phase proteins during tumor growth and after removal of the tumor may make their use attractive as biological markers of the response of the tumor-bearing animal to its tumor. 相似文献
57.
Arnaud Charolais Fouad Ammouri Elena Vyazmina Étienne Werlen Aaron Harris 《International Journal of Hydrogen Energy》2021,46(29):16019-16029
The fast filling time for hydrogen fuel cell vehicles makes them a user-friendly zero emission alternative to fossil fuel powered vehicles. The filling, by compressing gas into the vehicle tanks, produces heat that can be damaging. There are different protocols, standardized or the intellectual property of station operators, dedicated for different specific applications taking into account the specificity of the vessel and customer requirements. Standard protocols are developed for worst case conditions across a broad range of vehicle tank sizes and configurations. These worst case conditions do not result in the most economical equipment solution for hydrogen fueling. To ensure safety for different existing and future potential protocols a new “Safety Watchdog” approach is suggested in the current paper. This “Safety Watchdog” monitors the fueling process boundary conditions independently from the main process controls. The decoupling between the watchdog and the protocol allows use of protocols that are more economically beneficial while ensuring full safety conditions. The current paper provides a mathematical formulation of the Safety Watchdog as well as its validation versus modeling and field experimental data. 相似文献
58.
The aim of this work is to develop tools for optimal power flow management control in a micro grid (MG). The latter consists of a wind turbine, energy storage system, two gas turbines (GTs), and the main grid. Unlike the traditional approach, which is limited to the distribution of active power, this paper models an electrical system to coordinate and optimize the flow of both active and reactive power using discrete controls. The proposed optimal power distribution strategy has two objectives. First, it aims at forecasting over a time horizon of 24 hours the optimal distribution of the active and reactive power required for each power source connected to the MG. The proposed management incorporates the forecasts of consumption, weather, and tariffs. Second, it aims at reducing the CO2 emissions rate by optimizing both the operating point of the two GTs and the usage of the storage unit. The proposed optimization problem for the energy management system is solved using the Bellman algorithm through dynamic programming. Its effectiveness is illustrated with various simulations carried out in the Matlab environment. The supremacy of the proposed management algorithm is highlighted by comparing its performance with conventional (restricted) management. 相似文献
59.
Zebbiche Khalil Khelifi Fouad Loukhaoukha Khaled 《Multimedia Tools and Applications》2018,77(16):21281-21304
Multimedia Tools and Applications - In this paper, a robust additive image watermarking system operating in the Dual Tree Complex Wavelet Transform (DTCWT) domain is proposed. The system takes... 相似文献
60.
El‐Refaie Kenawy Fouad I. Abdel‐Hay Lamies Shahada Abd El‐Raheem R. El‐Shanshoury Mohamed H. El‐Newehy 《应用聚合物科学杂志》2006,102(5):4780-4790
New bactericidal polyamides with quaternary ammonium or phosphonium salts were prepared, and their antimicrobial activities were explored. The polyamides were synthesized by the polycondensation of diethyl‐l‐tartrate or chloromethylated diethyl‐l‐tartrate with ethylenediamine in dry absolute ethanol. The polyamides were modified to yield polymers with either quaternary ammonium or phosphonium salts. The polymers were characterized with elemental microanalysis and 1H‐NMR and IR spectra. The antimicrobial activity of the polymers bearing onium salts was studied against Gram‐negative bacteria (Escherichia coli, Pseudomones aeruginosa, Shigella sp., and Salmonella typhae), Gram‐positive bacteria (Bacillus subtilis and Bacillus cereus), and a fungus (Trichophytum rubrum) by the cut‐plug and viable‐cell‐count methods. Although all the polymers showed high antibacterial activity, some had no antifungal activity. The tributyl phosphonium salt of the polyamide was more effective against both Gram‐negative and Gram‐positive bacteria than the triethyl ammonium and triphenyl phosphonium salts of the polyamide. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4780–4790, 2006 相似文献