全文获取类型
收费全文 | 356篇 |
免费 | 28篇 |
学科分类
工业技术 | 384篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 13篇 |
2020年 | 17篇 |
2019年 | 10篇 |
2018年 | 10篇 |
2017年 | 11篇 |
2016年 | 22篇 |
2015年 | 18篇 |
2014年 | 20篇 |
2013年 | 27篇 |
2012年 | 18篇 |
2011年 | 21篇 |
2010年 | 33篇 |
2009年 | 19篇 |
2008年 | 23篇 |
2007年 | 21篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 11篇 |
2003年 | 4篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有384条查询结果,搜索用时 245 毫秒
101.
Egge SV Österberg U Aksnes A 《Journal of the Optical Society of America. A, Optics, image science, and vision》2012,29(6):1188-1198
In this paper a general method is presented for calculating the theoretical speckle contrast of a sum of correlated speckle patterns, motivated by the need to suppress the presence of speckle in laser projection displays. The method is applied to a specific example, where correlated speckle patterns are created by sequentially passing light through partially overlapping areas on a diffuser, before being projected onto a screen. This design makes it possible to find a simple expression for the correlation between speckle patterns. When the set of correlations involves symmetry, it is shown that the expression for the speckle contrast becomes simpler. The difference in performance between discretely and continuously varying speckle patterns is also investigated. In an example with speckle reduction by a rotating sinusoidal grating, it is found that continuous variation gives a speckle contrast that is 0.61 times the contrast obtained by discretely summing the maximum number of independent patterns. 相似文献
102.
103.
104.
Ben van Berkel Caroline Bos Astrid Piber Hannes Pfau Markus van Aalderen Juliane Maier Marc Salemink Andreas Bogenschuetz Marina Bozukova Brendon Carlin Miklos Deri Gary Freedman Juergen Heinzel Alexander Hugo Abhijit Kapade Marcin Koltunski Fernie Lai James Leng Tom Minderhoud Peter Moerland Rudi Nieveen Hans-Peter Nuenning Hyunil Oh Steffen Riegas Rikjan Scholten Ioana Sulea Christian Veddeler Rein Werkhoven Georg Willheim 《城市环境设计》2010,(1):36-39
杭州Raffles城发展坐落于浙江省省会杭州市的钱塘江边,是嘉德置地继新加坡、上海、北京、成都和巴林之后的第六栋,将零售店、办公楼、住户和酒店设施融于一体,成为新城区的文化地标。 相似文献
105.
Astrid Schumacher 《Datenschutz und Datensicherheit - DuD》2010,34(5):302-307
Künftige De-Mail-Provider müssen im Rahmen einer Akkreditierung durch das Bundesamt für Sicherheit in der Informationstechnik
die Umsetzung technischer und organisatorischer Ma?nahmen nachweisen. Dies umfasst neben der Sicherheit der angebotenen Dienste
die im Informationsverbund notwendige Interoperabilit?t und Funktionalit?t sowie die Erfüllung der datenschutzrechtlichen
Anforderungen. 相似文献
106.
Erik Hallberg Astrid Odeberg Glasenapp Magnus Lestelius 《Packaging Technology and Science》2005,18(2):89-95
The human visual system has an exceptional ability to detect systematic print mottle. One type of systematic print mottle is banding on printed corrugated board, resulting in a disturbing print defect. A new method that quantifies banding on printed corrugated board is proposed. The method is based on spatial frequency analysis, and the degree of banding is determined using a band‐pass filter range adapted to fit the flute wavelength and orientation of the acquired image of the printed board. The results for B‐flute corrugated board gave a correlation coefficient of 0.98 between the technical measurements and the subjective ratings. Methods of quantifying the banding on the different types of corrugated board available on the market are discussed. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
107.
Astrid C. John Thomas A. J. Kuhlbusch Heinz Fissan Günter Bröker Karl-Josef Geueke 《Aerosol science and technology》2013,47(9):694-702
Combustion and industrial processes are an important source of particles. Due to the new PM 10 and PM 2.5 standards for ambient air quality, a sampling system for PM 10/PM 2.5 in-stack measurements was designed and calibrated. In this new system, the exhaust gas is isokinetically sucked into a two stage impactor through the inlet of a plane filter device and the aerosol is fractionated in the particle size classes >10 w m, 10-2.5 w m, and <2.5 w m. Due to a relatively high volume flow (ca. 3.2 m 3 /h, depending on exhaust gas conditions), sampling times are kept short, e.g., 30 min for dust concentrations of 10 mg/m 3 . The impactor was calibrated in the laboratory and then operated at various industrial plants. Parallel measurements with identical devices showed average standard deviations of 3.1% (PM 10) and 3.4% (PM 2.5). Measurements of the cascade impactor together with the plane filter device gave plausible results and average PMx/TSP ratios of 0.49 (PM 2.5/TSP) and 0.78 (PM 10/TSP), showing a large variability for different processes. Elemental analysis using total-reflection X-ray fluorescence spectrometry, together with the size-fractionated sampling, proved to give characteristic patterns of the emitted aerosols, which can be used for a subsequent fingerprint modelling for source apportionment of ambient air pollution. 相似文献
108.
Summary: During the solidification of thin polymer layers different crack patterns can occur. There are several mechanisms of the development of regular crack defects and layer fractures. In case of self‐organization caused by Marangoni instability at the fluid layer surface the substrate can be periodically uncovered by spreading motions when dewetting hinders a back flow from the higher spots of the layer. Another type of crack patterns is generated from shrinkage processes and stress differences in the drying layer. Mostly these patterns are characterized by intersecting straight cracks. In this paper some examples of unusual shrinkage‐crack patterns in polymer layers are presented. Their propagation is independent on surface flow and surface deformations caused by the Marangoni effect, although the strength of polymer layers is impaired by the interfacial instability. Especially at layer edges or spots with thickness differences one can observe periodic wavy or circularly bend shrinkage‐crack structures. As a third type ramified surface defects are studied in thin layers. Often they only propagate at the layer surface.
109.
110.
Anomalous Resistance Hysteresis in Oxide ReRAM: Oxygen Evolution and Reincorporation Revealed by In Situ TEM 下载免费PDF全文
David Cooper Christoph Baeumer Nicolas Bernier Astrid Marchewka Camilla La Torre Rafal E. Dunin‐Borkowski Stephan Menzel Rainer Waser Regina Dittmann 《Advanced materials (Deerfield Beach, Fla.)》2017,29(23)
The control and rational design of redox‐based memristive devices, which are highly attractive candidates for next‐generation nonvolatile memory and logic applications, is complicated by competing and poorly understood switching mechanisms, which can result in two coexisting resistance hystereses that have opposite voltage polarity. These competing processes can be defined as regular and anomalous resistive switching. Despite significant characterization efforts, the complex nanoscale redox processes that drive anomalous resistive switching and their implications for current transport remain poorly understood. Here, lateral and vertical mapping of O vacancy concentrations is used during the operation of such devices in situ in an aberration corrected transmission electron microscope to explain the anomalous switching mechanism. It is found that an increase (decrease) in the overall O vacancy concentration within the device after positive (negative) biasing of the Schottky‐type electrode is associated with the electrocatalytic release and reincorporation of oxygen at the electrode/oxide interface and is responsible for the resistance change. This fundamental insight presents a novel perspective on resistive switching processes and opens up new technological opportunities for the implementation of memristive devices, as anomalous switching can now be suppressed selectively or used deliberately to achieve the desirable so‐called deep Reset. 相似文献