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31.
Santos JA Ranjbar S Neto VF Ruch D Grácio J 《Journal of nanoscience and nanotechnology》2012,12(8):6822-6827
Although large focus has been placed into the deposition of nanocrystalline and ultra-nanocrystalline diamond films, most of this research uses microwave plasma assisted CVD systems. However, the growth conditions used in microwave systems cannot be directly used in hot-filament CVD systems. This paper, aims to enlarge the knowledge of the diamond film depositing process. H2/CH4/Ar gas mixtures have been used to deposit micro, nano and ultra-nanocrystalline diamond films by hot-filament CVD systems. Additionally, the distance between the filaments array and the substrate was varied, in order to observe its effect and consequently the effect of a lower substrate temperature in the nucleation density and deposition. All the samples were characterized for microstructure and quality, using scanning electron microscopy and Raman spectroscopy. 相似文献
32.
In this paper a new algorithm for allocating energy and determining the optimum amount of network active power reserve capacity and the share of generating units and demand side contribution in providing reserve capacity requirements for day-ahead market is presented. In the proposed method, the optimum amount of reserve requirement is determined based on network security set by operator. In this regard, Expected Load Not Supplied (ELNS) is used to evaluate system security in each hour. The proposed method has been implemented over the IEEE 24-bus test system and the results are compared with a deterministic security approach, which considers certain and fixed amount of reserve capacity in each hour. This comparison is done from economic and technical points of view. The promising results show the effectiveness of the proposed model which is formulated as mixed integer linear programming (MILP) and solved by GAMS software. 相似文献
33.
Comb polycarboxylic acid dispersants (CPCADs) graft acrylic copolymers which consist of hanging methoxy polyethylene glycol chains and carboxylic acid groups on main acrylic chain. The CPCADs have been synthesized by radical polymerization of methacrylic acid and methoxy polyethylene glycol methacrylate as a nonionic unsaturated hydrophilic macromonomer. The CPCADs are polymeric surfactants that can be used as anionic dispersant. Methoxy polyethylene glycol methacrylate has been synthesized by esterification of methacrylic acid and methoxy polyethylene glycol in the presence of methanesulfonic acid as catalyst. These have been characterized with 1H‐NMR and GPC. Acid values of CPCA dispersants have been determined. The dispersion of CPCA dispersants depends on their molecular weights, length mPEG, and acid values. Dispersion of titanium dioxide in typical solvent‐based paint formulation has been investigated. The physicochemical and mechanical properties of surface coatings having CPCADs such as gloss, hardness, and contrast ratio have been investigated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
34.
DNA nanotechnology is a novel approach for synthesis of DNA-based nanostructures. Stem-loops, nanojunctions, sticky-ends and periodic lengths of DNA are the most essential nanostructures in DNA nanofabrications. Loop-mediated isothermal amplification (LAMP) is a powerful technology for repetitive synthesis of double-stranded and cauliflower-like DNAs. The process leads to long and repetitive sequences of DNAs, which are fabricated via loop primers. The authors demonstrate here scanning tunneling micrographs of LAMP-synthesised DNAs deposited on highly ordered pyrolytic graphite. The scans are compared with natural DNAs. Scanning tunneling microscopy (STM) images indicated the creation of periodic long DNAs, stem-looped DNAs and three-way DNA nanojunctions. It is also suggested that such nanomaterials could be promising candidates for use in DNA-based nanodevices. 相似文献
35.
Sh. Ghassemzadeh M. Schaffie A. Sarrafi M. Ranjbar 《Petroleum Science and Technology》2013,31(24):2969-2975
This article presents a new model in predicting dew point pressure, which is reduced the complexities of the prior fuzzy model by implementing genetic algorithm as a feature recognition tool. Feature recognition is a tool that makes the problem less complex and create the opportunity to have a better model. In this study, 15 parameters decreased to six by using the feature recognition tool. This tool discovered if fuzzy model inputs include reservoir temperature and mole fractions of H2S, N2, C3, iC5, and C6, the proposed model captures the physical trend better than previous models. The recommended model has an average relative deviation of 1.16% and average absolute deviation of 3.08% for testing data points. 相似文献
36.
Shahri Seyyed Ehsan Eftekhari Lakhi Mohammad Ranjbar Sadegh 《Journal of Mechanical Science and Technology》2021,35(3):979-985
Journal of Mechanical Science and Technology - Determining the material deformation behavior including local strain data is very useful for analyzing the forming processes. In order to measure... 相似文献
37.
Polyformamidine‐Derived Non‐Noble Metal Electrocatalysts for Efficient Oxygen Reduction Reaction 下载免费PDF全文
Laura C. Pardo Pérez Nastaran Ranjbar Sahraie Julia Melke Patrick Elsässer Detre Teschner Xing Huang Ralph Kraehnert Robin J. White Stephan Enthaler Peter Strasser Anna Fischer 《Advanced functional materials》2018,28(22)
A facile approach for the template‐free synthesis of highly active non‐noble metal based oxygen reduction reaction (ORR) electrocatalysts is presented. Porous Fe?N?C/Fe/Fe3C composite materials are obtained by pyrolysis of defined precursor mixtures of polyformamidine (PFA) and FeCl3 as nitrogen‐rich carbon and iron sources, respectively. Selection of pyrolysis temperature (700–1100 °C) and FeCl3 loading (5–30 wt%) yields materials with differing surface areas, porosity, graphitization degree, nitrogen and iron content, as well as ORR activity. While the ORR activity of Fe‐free materials is limited (i.e., synthesized from pure PFA), a huge increase in activity is observed for catalysts containing Fe, revealing the participation of the metal dopant in the construction of active electrocatalytic sites. Further activity improvement is achieved via acid‐leaching and repeated pyrolysis, a result which is attributed to the creation of new active sites located at the surface of the porous nitrogen‐doped carbon by dissolution of the Fe and Fe3C nanophases. The best performing catalyst, which was synthesized with a low Fe loading (i.e., 5 wt%) and at a pyrolysis temperature of 900 °C, exhibits high activity, excellent H2O selectivity, extended stability, in both basic and acidic media as well as a remarkable tolerance toward methanol. 相似文献
38.
Mani Ranjbar William G. Macready Lane Clark Frank Gaitan 《Quantum Information Processing》2016,15(9):3519-3542
Ramsey theory is an active research area in combinatorics whose central theme is the emergence of order in large disordered structures, with Ramsey numbers marking the threshold at which this order first appears. For generalized Ramsey numbers r(G, H), the emergent order is characterized by graphs G and H. In this paper we: (i) present a quantum algorithm for computing generalized Ramsey numbers by reformulating the computation as a combinatorial optimization problem which is solved using adiabatic quantum optimization; and (ii) determine the Ramsey numbers \(r({\mathscr {T}}_{m},{\mathscr {T}}_{n})\) for trees of order \(m,n = 6,7,8\), most of which were previously unknown. 相似文献
39.
Sheiati Shohreh Ranjbar Navid Frellsen Jes Skare Elisabeth L. Cepuritis Rolands Jacobsen Stefan Spangenberg Jon 《Neural computing & applications》2021,33(19):13027-13037
Neural Computing and Applications - For the past decades, computational fluid dynamics (CFD) simulations have been shown as a promising approach for understanding the complex flow behavior of... 相似文献
40.
Mostafa Yousefi Maryam Ranjbar 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(3):633-640
In the present study nano-sized strontium-doped lanthanum manganite, La0.75Sr0.25MnO3 (LSM), were synthesized by three simple different methods (a) co-precipitation, (b) ultrasonic and (c) microwave-assisted co-precipitation. A lanthanum(III) coordination polymer, [pyda.H]2[La2(pydc)4(H2O)4]·2H2O, where [pyda.H]+?=?2,6-diaminopyridinium, and (pydc)2??=?2,6-pyridinedicarboxylate, was used as a new precursor. The products were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), field emission scanning electron microscope (FESEM), thermal gravimetric (TG) and differential thermal analyses (DTA), as well as by Energy-dispersive X-ray spectroscopy (EDX). The XRD results showed that the crystal lattice of the product obtained was orthorhombic perovskite structure. The porosity, particle size and homogeneity of calcinated LSM were strongly dependent on the preparation method. In addition, the results proved that the product formation time was decreased considerably when ultrasonic or microwave irradiation methods were used. 相似文献