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排序方式: 共有523条查询结果,搜索用时 531 毫秒
91.
Heiko T. Liebel Marie S. Stølen Bjørn S. Frengstad Randi K. Ramstad Bjørge Brattli 《Bulletin of Engineering Geology and the Environment》2012,71(2):235-243
Thermal response tests (TRTs) are used to measure the effective thermal conductivity in boreholes. The results serve as a
basis for the dimensioning of commercial ground-source heat pump installations with closed loop systems. The study evaluated
the reliability of TRTs performed in winter by comparing two TRTs carried out under very different winter weather conditions.
A third TRT elucidated the influence of convection in wells with a higher heat input. Rock cores were analysed for quartz
content and these results and the laboratory-measured thermal conductivity data were compared with the TRT results. This highlighted
the importance of the distribution and orientation of minerals in the rock, and that a high quartz content does not necessarily
give high thermal conductivity values. It is concluded that winter TRTs give useful results if additional temperature loggers
are installed in anticipated fracture zones to detect groundwater flow and to survey the effect of infiltrating water. 相似文献
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Andrzej Dziedzic Leszek J. Golonka Jaroslaw Kita Heiko Thust Karl-Heinz Drue Reinhard Bauer Lars Rebenklau Klaus-Jurgen Wolter 《Microelectronics Reliability》2001,41(5)
This paper presents systematic investigations of electrical and stability properties of various low temperature co-fired ceramics (LTCC) resistors. One of the goals of this work was to check the compatibility of LTCC materials (tapes, resistive and conductive inks) from various manufacturers. Three commercially available green tapes and three LTCC resistor/conductor systems were examined. The resistive inks with 1 kΩ/sq. nominal sheet resistance were used. Buried (inside) and surface resistors were laminated and fired according to the tape manufacturers’ recommendations. The influence of dimensional effect on sheet resistance and hot temperature coefficient of resistance, the temperature dependence of resistance in a wide temperature range (from −180°C to +130°C), long-term stability of thermally aged as-fired resistors (150°C, 500 h) and durability to high-voltage micro- or nanosecond pulses (50 ns pulses with 4000 V/mm maximum electric field or 10 μs ones with 700–1000 V/mm electrical field) were carried out for electrical and stability characterisation of LTCC resistors. Non-destructive scanning acoustic microscope diagnostics was applied for structure investigation and estimation of lamination and cofiring process quality of buried LTCC resistors. 相似文献
95.
Martin Schaper Jan Schmidt Heiko Plagwitz Rolf Brendel 《Progress in Photovoltaics: Research and Applications》2005,13(5):381-386
We have developed a crystalline silicon solar cell with amorphous silicon (a‐Si:H) rear‐surface passivation based on a simple process. The a‐Si:H layer is deposited at 225°C by plasma‐enhanced chemical vapor deposition. An aluminum grid is evaporated onto the a‐Si:H‐passivated rear. The base contacts are formed by COSIMA (contact formation to a‐Si:H passivated wafers by means of annealing) when subsequently depositing the front silicon nitride layer at 325°C. The a‐Si:H underneath the aluminum fingers dissolves completely within the aluminum and an ohmic contact to the base is formed. This contacting scheme results in a very low contact resistance of 3.5 ±0.2 mΩ cm2 on low‐resistivity (0.5 Ω cm) p‐type silicon, which is below that obtained for conventional Al/Si contacts. We achieve an independently confirmed energy conversion efficiency of 20.1% under one‐sun standard testing conditions for a 4 cm2 large cell. Measurements of the internal quantum efficiency show an improved rear surface passivation compared with reference cells with a silicon nitride rear passivation. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
96.
Approaching Gas Phase Electrodeposition: Process and Optimization to Enable the Self‐Aligned Growth of 3D Nanobridge‐Based Interconnects 下载免费PDF全文
97.
Gia Quyet Ngo Antony George Robin Tristan Klaus Schock Alessandro Tuniz Emad Najafidehaghani Ziyang Gan Nils C. Geib Tobias Bucher Heiko Knopf Sina Saravi Christof Neumann Tilman Lühder Erik P. Schartner Stephen C. Warren-Smith Heike Ebendorff-Heidepriem Thomas Pertsch Markus A. Schmidt Andrey Turchanin Falk Eilenberger 《Advanced materials (Deerfield Beach, Fla.)》2020,32(47):2003826
Atomically thin transition metal dichalcogenides are highly promising for integrated optoelectronic and photonic systems due to their exciton-driven linear and nonlinear interactions with light. Integrating them into optical fibers yields novel opportunities in optical communication, remote sensing, and all-fiber optoelectronics. However, the scalable and reproducible deposition of high-quality monolayers on optical fibers is a challenge. Here, the chemical vapor deposition of monolayer MoS2 and WS2 crystals on the core of microstructured exposed-core optical fibers and their interaction with the fibers’ guided modes are reported. Two distinct application possibilities of 2D-functionalized waveguides to exemplify their potential are demonstrated. First, the excitonic 2D material photoluminescence is simultaneously excited and collected with the fiber modes, opening a novel route to remote sensing. Then it is shown that third-harmonic generation is modified by the highly localized nonlinear polarization of the monolayers, yielding a new avenue to tailor nonlinear optical processes in fibers. It is anticipated that the results may lead to significant advances in optical-fiber-based technologies. 相似文献
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Proffitt Dennis R.; Rock Irvin; Hecht Heiko; Schubert Jim 《Canadian Metallurgical Quarterly》1992,18(1):3
The stereokinetic effect (SKE) has been defined and studied by nested circular patterns rotating on a turntable. Circles must appear not to rotate as they revolve, which in turn results in their appearing to translate relative to one another. A powerful illusion of object depth results even though the individual circles do not undergo an appropriate foreshortening consistent with their apparent changes in slant. It is suggested and tested that the SKE is based on the changing positions between the nested contours despite the absence of any change within each contour, whereas the kinetic depth effect (KDE) entails both kinds of change. It follows that a turntable method of presentation is not necessary, and between-contour transformations can be stimulated by computer animation. Displays consisting of simple translations were shown to evoke robust depth impressions as were patterns consisting of contours of varying shapes. Comparisons of the depth, compellingness, and rigidity of matched SKE and KDE displays are reported. The SKE is taken to be paradigmatic for how the visual system perceives depth when observing small object rotations that occur in everyday situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献