全文获取类型
收费全文 | 323篇 |
免费 | 24篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 100篇 |
金属工艺 | 4篇 |
机械仪表 | 2篇 |
建筑科学 | 11篇 |
能源动力 | 7篇 |
轻工业 | 12篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
武器工业 | 1篇 |
无线电 | 19篇 |
一般工业技术 | 112篇 |
冶金工业 | 40篇 |
原子能技术 | 6篇 |
自动化技术 | 27篇 |
出版年
2023年 | 4篇 |
2021年 | 9篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 14篇 |
2017年 | 13篇 |
2016年 | 18篇 |
2015年 | 7篇 |
2014年 | 15篇 |
2013年 | 26篇 |
2012年 | 10篇 |
2011年 | 27篇 |
2010年 | 15篇 |
2009年 | 18篇 |
2008年 | 16篇 |
2007年 | 15篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 13篇 |
2002年 | 9篇 |
2001年 | 3篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有348条查询结果,搜索用时 15 毫秒
341.
Šárka Houdková Zdeněk Česánek Eva Smazalová František Lukáč 《Journal of Thermal Spray Technology》2018,27(1-2):179-195
Three commercially available chromium carbide-based powders with different kinds of matrix (Cr3C2-25%NiCr; Cr3C2-25%CoNiCrAlY and Cr3C2-50%NiCrMoNb) were deposited by an HVOF JP-5000 spraying gun, evaluated and compared. The influence of heat treatment on the microstructure and properties, as well as the oxidation resistance in a hot steam environment (p = 24 MPa; T = 609 °C), was evaluated by SEM and XRD with respect to their potential application in the steam power industry. The sliding wear resistance measured at room and elevated (T = 600 °C) temperatures according to ASTM G-133. For all three kinds of chromium carbide-based coatings, the precipitation of secondary carbides from the supersaturated matrix was observed during the heat treatment. For Cr3C2-25%NiCr coating annealed in hot steam environment as well as for Cr3C2-25%CoNiCrAlY coating in both environments, the inner carbide oxidation was recorded. The sliding wear resistance was found equal at room temperature, regardless of the matrix composition and content, while at elevated temperatures, the higher wear was measured, varying in dependence on the matrix composition and content. The chromium carbide-based coating with modified matrix composition Cr3C2-50%NiCrMoNb is suitable to replace the Cr3C2-25%NiCr coating in a hot steam environment to eliminate the risk of failure caused by inner carbide oxidation. 相似文献
342.
Two structurally different copper(II) complexes of the compositions [{Cu(9dhx)(H2O)3}2(µ-SO4)2] (1) and [Cu(9dhx)2(H2O)2(NO3)2]·H2O (2), involving 9-deazahypoxanthine (9dhx; 6-oxo-9-deazapurine; 9-deazahypoxanthine), have been prepared and characterized by elemental analysis, infrared and electronic spectroscopy, electrospray ionisation (ESI) mass spectrometry, thermogravimetric (TG) and differential thermal (DTA) analyses, and cyclic voltammetry. The X-ray structures of complexes 1 and [Cu(9dhx)2(H2O)2(NO3)2] (2a) revealed the distorted octahedral geometry in the vicinity of the copper(II) atoms, with the NO5 and N2O4 donor set, respectively. In the dimeric compound 1, the {Cu(9dhx)(H2O)3}2 units are bridged by sulfate groups with the Cu···Cu separation being 5.3446(2) Å. In both structures the 9dhx ligands are coordinated through the N3 atoms of the pyrimidine moieties. The SOD-like activity of complexes 1 and 2 was evaluated in vitro showing moderate effect, with the IC50 values equal to 18.20, and 53.33 μM, respectively. 相似文献
343.
Josef Kameník Alena Saláková Zdeněk Pavlík Gabriela Bořilová Radka Hulanková Iva Steinhauserová 《European Food Research and Technology》2014,239(3):395-402
Physicochemical, instrumental and microbiological examinations of steaks of beef and pork (m. longissimus lumborum) in vacuum skin packaging (VSP), conventional vacuum packing (CVP) and modified atmosphere packaging (MAP) were performed. Samples were stored at 2 ± 0.5 °C for 3 (pork) or 5 (beef) weeks. No statistically significant changes in pH values were recorded. Statistically significant (p < 0.001) changes in the thiobarbituric reactive substances content in modified atmosphere packed beef samples, and differences between samples in MAP and VSP or CVP were found from week 2 of the experiment onwards. The biggest changes in colour parameters were found in beef samples in MAP. The lowest and highest purge loss was recorded in samples in VSP and CVP, respectively. Vacuum packing enhanced the growth of lactic acid bacteria (LAB). At the end of the experiment, their numbers ranged from 4.31 log10 cfu g?1 (pork in CVP) to 5.14 log10 cfu g?1 (beef in VSP). LAB populations reached 2 log10 cfu g?1 in MAP beef and pork samples. On the other hand, MAP enabled the development of bacteria of the genus Pseudomonas and Brochothrix thermosphacta. The highest increase in coliform bacteria counts was recorded in vacuum-packed pork. 相似文献
344.
In this article we report on results obtained using a newly developed self-consistent fully 3D Particle-In-Cell code for modelling of plasma-solid interaction.The model presented here involves a hollow cylindrical chamber opened to the plasma, with a thin cylindrical guard at the inlet and a strong external magnetic field limiting access of charged particles to the cylindrical wall. This model layout might provide more insight into processes taking place during magnetron deposition of thin films onto porous media. It is also a basis for probe diagnostics in fusion plasma research.The magnetic field is either parallel or slightly inclined with respect to the cylindrical axis. The results presented are axial and azimuthal ion current densities and cumulative distribution functions of ions impinging on the cylindrical surface for several angles of magnetic field inclination. They confirm the importance of proper alignment with magnetic field in certain geometries.Efficiency and possibilities of further extensions to the 3D model are also briefly discussed. 相似文献
345.
Fabrizio Guzzetta Cameron W. Jellett Jalal Azadmanjiri Pradip Kumar Roy Saeed Ashtiani Karel Friess Zdeněk Sofer 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(12):2206430
The attention on group III-VI compounds in the last decades has been centered on the optoelectronic properties of indium and gallium chalcogenides. These outstanding properties are leading to novel advancements in terms of fundamental and applied science. One of the advantages of these compounds is to present laminated structures, which can be exfoliated down to monolayers. Despite the large knowledge gathered toward indium and gallium chalcogenides, the family of the group III-VI compounds embraces several other noncommon compounds formed by the other group III elements. These compounds present various crystal lattices, among which a great deal is offered from layered structures. Studies on aluminium chalcogenides show interesting potential as anodes in batteries and as semiconductors. Thallium (Tl), which is commonly present in the +1 oxidation state, is one of the key components in ternary chalcogenides. However, binary Tl–Q (Q = S, Se, Te) systems and derived films are still studied for their semiconducting and thermoelectric properties. This review aims to summarize the biggest features of these unusual materials and to shed some new light on them with the perspective that in the future, novel studies can revive these compounds in order to give rise to a new generation of technology. 相似文献
346.
Lukáš Zdražil Zdeněk Baďura Michal Langer Sergii Kalytchuk David Panáček Magdalena Scheibe Štěpán Kment Hana Kmentová Muhammed Arshad Thottappali Elmira Mohammadi Miroslav Medveď Aristides Bakandritsos Giorgio Zoppellaro Radek Zbořil Michal Otyepka 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(32):2370251
Photoactivation of aspartic acid-based carbon dots (Asp-CDs) induces the generation of spin-separated species, including electron/hole (e−/h+) polarons and spin-coupled triplet states, as uniquely confirmed by the light-induced electron paramagnetic resonance spectroscopy. The relative population of the e−/h+ pairs and triplet species depends on the solvent polarity, featuring a substantial stabilization of the triplet state in a non-polar environment (benzene). The electronic properties of the photoexcited Asp-CDs emerge from their spatial organization being interpreted as multi-layer assemblies containing a hydrophobic carbonaceous core and a hydrophilic oxygen and nitrogen functionalized surface. The system properties are dissected theoretically by density functional theory in combination with molecular dynamics simulations on quasi-spherical assemblies of size-variant flakelike model systems, revealing the importance of size dependence and interlayer effects. The formation of the spin-separated states in Asp-CDs enables the photoproduction of hydrogen peroxide (H2O2) from water and water/2-propanol mixture via a water oxidation reaction. 相似文献
347.
Michał Sobaszek Maria Brzhezinskaya Adrian Olejnik Vincent Mortet Mahebub Alam Mirosław Sawczak Mateusz Ficek Maria Gazda Zdeněk Weiss Robert Bogdanowicz 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(26):2208265
Polycrystalline boron-doped diamond is a promising material for high-power aqueous electrochemical applications in bioanalytics, catalysis, and energy storage. The chemical vapor deposition (CVD) process of diamond formation and doping is totally diversified by using high kinetic energies of deuterium substituting habitually applied hydrogen. The high concentration of deuterium in plasma induces atomic arrangements and steric hindrance during synthesis reactions, which in consequence leads to a preferential (111) texture and more effective boron incorporation into the lattice, reaching a one order of magnitude higher density of charge carriers. This provides the surface reconstruction impacting surficial populations of C C dimers, C H, CO groups, and COOH termination along with enhanced kinetics of their abstraction, as revealed by high-resolution core-level spectroscopies. A series of local densities of states were computed, showing a rich set of highly occupied and localized surface states for samples deposited in deuterium, negating the connotations of band bending. The introduction of enhanced incorporation of boron into (111) facet of diamond leads to the manifestation of surface electronic states below the Fermi level and above the bulk valence band edge. This unique electronic band structure affects the charge transfer kinetics, electron affinity, and diffusion field geometry critical for efficient electrolysis, electrocatalysis, and photoelectrochemistry. 相似文献
348.
Dr.-Ing. Vojtěch Turek Dr.-Ing. Zdeněk Jegla Dipl.-Ing. Miloslav Dohnal Prof. Dr.-Ing. Marcus Reppich 《化学,工程师,技术》2023,95(9):1441-1447
This is the first part of a two-part paper focusing on the assessment of accuracy of turbulence-related data from computational fluid dynamics (CFD) simulations using effective numerical dissipation rate and effective numerical viscosity. Setup of the CFD cases replicating a swirling pipe flow experiment from literature, for which turbulence-related data measured via laser Doppler anemometry (LDA) had been reported, is presented. The way effective numerical dissipation rate and effective numerical viscosity were obtained for each mesh cell is also discussed. The results of the study are presented in the second part of this series. 相似文献