全文获取类型
收费全文 | 186篇 |
免费 | 11篇 |
专业分类
综合类 | 1篇 |
化学工业 | 47篇 |
金属工艺 | 4篇 |
机械仪表 | 4篇 |
建筑科学 | 12篇 |
能源动力 | 8篇 |
轻工业 | 27篇 |
水利工程 | 3篇 |
无线电 | 13篇 |
一般工业技术 | 35篇 |
冶金工业 | 24篇 |
原子能技术 | 4篇 |
自动化技术 | 15篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 3篇 |
2014年 | 10篇 |
2013年 | 10篇 |
2012年 | 13篇 |
2011年 | 11篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 10篇 |
2002年 | 3篇 |
1999年 | 7篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1962年 | 2篇 |
1956年 | 1篇 |
1955年 | 2篇 |
1954年 | 4篇 |
1939年 | 1篇 |
排序方式: 共有197条查询结果,搜索用时 31 毫秒
51.
Detre Teschner Ramzi Farra Lide Yao Robert Schlögl Hary Soerijanto Reinhard Schomäcker Timm Schmidt László Szentmiklósi Amol P. Amrute Cecilia Mondelli Javier Pérez-Ramírez Gerard Novell-Leruth Núria López 《Journal of Catalysis》2012,285(1):273-284
Rationally designed RuO2-based Deacon catalysts can contribute to massive energy saving compared to the current electrolysis process in chemically recycling HCl to produce molecular chlorine. Here, we report on our integrated approach between state-of-the-art experiments and calculations. The aim is to understand industrial Deacon catalyst in its realistic surface state and to derive mechanistic insights into this sustainable reaction. We show that the practically relevant RuO2/SnO2 consists of two major RuO2 morphologies, namely 2–4 nm-sized particles and 1–3-ML-thick epitaxial RuO2 films attached to the SnO2 support particles. A large fraction of the small nanoparticles expose {1 1 0} and {1 0 1} facets, whereas the film grows with the same orientations, due to the preferential surface orientation of the rutile-type support. Steady-state Deacon kinetics indicate a medium-to-strong positive effect of the partial pressures of reactants and deep inhibition by both water and chlorine products. Temporal Analysis of Products and in situ Prompt Gamma Activation Analysis strongly suggest a Langmuir–Hinshelwood mechanism and that adsorbed Cl poisons the surface. Under relevant operation conditions, the reactivity is proportional to the coverage of a specific atomic oxygen species. On the extensively chlorinated surface that can be described as surface oxy-chloride, oxygen activation is the rate-determining step. DFT-based micro-kinetic modeling reproduced all experimental observations and additionally suggested that the reaction is structure sensitive. Out of the investigated models, the 2 ML RuO2 film-covered SnO2 gives rise to significantly higher reactivity than the (1 0 1) surface, whereas the 1 ML film seems to be inactive. 相似文献
52.
Thorsten Timm 《国际生产研究杂志》2013,51(12):3431-3453
Growing competition creates pressure among companies to run their production in a cost-optimal way and yet adapt immediately to changes in their environmental conditions. Decisions must always consider the integration of the companies in globalised markets on both the demand and supply side. This paper deals with the optimal planning of decisions concerning the structure and dimension of production facilities. The methods used for material requirements planning are selected and configured according to these decisions. These decision problems are represented in the form of four hierarchically layered partial models, each of them realised and iteratively solved by a mathematical optimisation model. The hierarchical planning method is evaluated using a practical case example based on a valve production system of a manufacturing company. 相似文献
53.
Ralph Dring Jens Hoffmeyer Timm Seeger Michael Vormwald 《Computational Materials Science》2003,28(3-4):587-596
There is increasing demand for analytical methods that estimate the fatigue life of engineering components and structures with a high degree of accuracy. The fatigue life is determined by the stress–strain sequences at the critical locations. Therefore, these sequences have be calculated with sufficient accuracy for arbitrary nonproportional cyclic loading. Based on the experience with a variety of material models following macroscale continuum mechanics approaches, an improved set of constitutive equations is proposed. The stress–strain behaviour of a commercial structural steel has been investigated experimentally. Firstly, the results of this experimental study serve to identify the material parameters comprised in the model. Secondly, the predicted stress–strain paths are compared to their experimentally determined counterparts as well as to paths predicted by other models. The overall accuracy of the proposed model is quite satisfying, especially as far as calculated amplitudes are concerned. 相似文献
54.
James L. Webb Olof Persson Kimberly A. Dick Claes Thelander Rainer Timm Anders Mikkelsen 《Nano Research》2014,7(6):877-887
Gated transport measurements are the backbone of electrical characterization of nanoscale electronic devices. Scanning gate microscopy (SGM) is one such gating technique that adds crucial spatial information, accessing the localized properties of semiconductor devices. Nanowires represent a central device concept due to the potential to combine very different materials. However, SGM on semiconductor nanowires has been limited to a resolution in the 50-100 nm range. Here, we present a study by SGM of newly developed III-V semiconductor nanowire InAs/GaSb heterojunction Esaki tunnel diode devices under ultra-high vacuum. Sub-5 nm resolution is demonstrated at room temperature via use of quartz resonator atomic force microscopy sensors, with the capability to resolve InAs nanowire facets, the InAs/GaSb tunnel diode transition and nanoscale defects on the device. We demonstrate that such measurements can rapidly give important insight into the device properties via use of a simplified physical model, without the requirement for extensive calculation of the electrostatics of the system. Interestingly, by precise spatial correlation of the device electrical transport properties and surface structure we show the position and existence of a very abrupt (〈10 nm) electrical transition across the InAs/GaSb junction despite the change in material composition occurring only over 30-50 nm. The direct and simultaneous link between nanostructure composition and electrical properties helps set important limits for the precision in structural control needed to achieve desired device performance. 相似文献
55.
Attempted to replicate previous demonstrations of classical conditioning of morphine analgesic tolerance and to determine whether stimulus overshadowing effects might explain previous conflicting findings. In Exp I, 8 groups of male Sprague-Dawley rats received a series of 10 morphine (5 mg/kg) and/or saline injections, differing only with respect to the contingency between a compound visual-auditory CS and the substance injected. When tested for analgesic responding to morphine in the presence of the compound CS, only those groups for which the CS and morphine injections were paired during the acquisition sequence evidenced tolerance. In Exp II, tolerant Ss were tested in the presence of 1 component of the compound CS. When a loud tone (85 db) was used in the compound, less analgesic tolerance was elicited later by the weaker visual stimulus alone. This differential stimulus control of the analgesic response suggests that overshadowing may contribute to failures to replicate conditioned morphine tolerance. It is possible that internal morphine-produced stimuli may overshadow external cues. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
M. Rohrlich E. Kuchinke G. Brückner W. Essner E. Timm A. Hesse L. Acker Ch. Nernst H. Janecke G. Brückner F. Egger H. -D. Cremer A. Herzer R. Rasmus E. Drews A. Menger H. Franke J. Schwaibold und J. Gutschmidt 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1954,98(5):388-394
Ohne Zusammenfassung 相似文献
57.
E. Timm H. Thaler und F. Sierp 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1954,99(6):468-469
Ohne Zusammenfassung 相似文献
58.
G Timm 《Canadian Metallurgical Quarterly》1976,168(4):537-543
A presentation is given of the severe changes in the retina of a 26-year-old man caused by intraocular Calciumoxalate crystals with clinical, histological and polarizing optical findings. The stadia of the retinopathia oxalogenica are classified here. 相似文献
59.
Thies Timm 《Materialwissenschaft und Werkstofftechnik》1970,1(2):63-70
Elastomers. Physical properties concerning the difference to other plastics The definitions concerning the terms “Elastomer” and “Rubber” given by the ASTM-D 1418–67 and ASTM-D 1566–68 as well as by the corresponding Draft ISO Recommendation 1382 are contradictory one with another and moreover individually are unsufficient to fix limits of other polymeric materials. In this respect the DIN-Proposal 7724 (February 1969) can be regarded as an substantial progress, since it avoids complications arising from including raw materials and preliminary products and since — apart from the special chemical structure — it classifies polymers with the aid of their temperature function of shear modulus, and of the mechanical loss factor only. The habit of the curves obtained, the glass transition point and the modulus level within the rubber-elastic range leads to the classification into: Thermoplastics (Plastomers) — Elastomers — Thermoelastics and Duromers. Possibilities and limitations of this method are tested on 29 polymers (crosslinked and uncrosslinked) and by the results obtained the usefullness of this classification-system can be approved as positive in most cases. 相似文献
60.