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51.
By using the characteristics of a hydrogen-absorbing alloy, the hydrogen produced by catalytic dehydrogenation of saturated
compounds can be absorbed to form metal hydrides, and, vice versa, the resulting metal hydrides are able to hydrogenate efficiently
unsaturated compounds upon dehydriding. Gas-phase reactions between 2-butene and 2-propanol on a hydrogen-absorbing alloy
CaNi5 have been studied in the temperature range of 393–473 K. CaNi5 showed interesting characteristics as an active catalyst for the catalytic transfer hydrogenation of butene from propanol
as a hydrogen donor. 2-propanol was effectively dehydrogenated at 423 K to yield acetone in which the dissociated hydrogen
was completely absorbed by CaNi5 to form the metal hydride. When the alloy was hydrided to some extent, butene was hydrogenated by the absorbed hydrogen in
the metal hydride to produce butane. The overall reaction on CaNi5 was expressed as catalytic transfer hydrogenation of 2-butene from 2-propanol through intermediate formation of metal hydrides,
rather than the direct reaction between butene and propanol on the alloy. Thus, CaNi5 effectively repeated hydriding–dehydriding cycles: hydriding of CaNi5 by 2-propanol dehydrogenation with subsequent dehydriding for the hydrogenation of 2-butene. The use of hydrogen-absorbing
CaNi5 provides a novel reaction system for the catalytic transfer hydrogenation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
52.
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54.
Yoshihisa Maeyama Kazunori Kadota Akira Kitayama Yuichi Tozuka Mikio Yoshida Atsuko Shimosaka Yoshiyuki Shirakawa 《International Journal of Hydrogen Energy》2017,42(16):11501-11509
A hybrid simulation was carried out using discrete variational (DV) Xα molecular orbital and molecular dynamics methods to examine the storage of hydrogen in metal nanoparticles. The calculation load was light and therefore could be performed quickly on a generic personal computer. The simulation investigates the electronic states of hydrogen on Pd and Ti nanoparticles. The hydrogen dissociation behavior on the metal surface was reproduced, and the calculated bonding orbitals of Pd and hydrogen are consistent with other reports. The diffusion coefficient of hydrogen inside the metal displays the same temperature dependence as the theoretical results. This simplified calculation, which produces results in agreement with experimental/theoretical values, could lead to improved simulation methods for hydrogen storage materials. 相似文献
55.
Kazuyoshi Torii Kenichi Shoji Hiroshi Kawakami Takao Kumihashi Toshihiko Itoga Natsuki Yokoyama Masahiro Moniwa Tooru Kaga Yoshihisa Fujisaki 《Electrical Engineering in Japan》1997,121(1):43-50
A one-mask-patterned ferroelectric capacitor test structure designed with a 0.5-μm feature size was fabricated. Oxygen plasma treatment after dry etching decreased the leakage current to as low as that of as-deposited film. These one-mask-patterned ferroelectric capacitors, with switching charge almost equal to as-deposited film, were successfully fabricated. Ferroelectric memories as dense as dynamic random access memories will become possible with this technology. However, the leakage current density for micron-sized capacitors is 2 to 10 times that of large capacitors. The leakage current in small capacitors is increased due to perimeter leakage that runs through the damaged region on the capacitor sidewall. © Scripta Technica, Inc. Electr Eng Jpn, 121(1): 43–50, 1997 相似文献
56.
Shigeyuki Nakamura Yoshihisa Mori Ken’ichi Takarabe 《Journal of Electronic Materials》2014,43(6):2174-2178
High-performance Mg2Si thermoelectric devices have been obtained by spark plasma sintering of high-purity, pre-synthesized, all-molten Mg2Si powder. We studied the effects of source powder particle size on thermoelectric performance. To improve the performance, further investigation of the microstructure of the devices is needed. In this work we studied the microstructure of grain boundaries and interfaces between electrodes and Mg2Si sintered bodies to increase understanding of Mg2Si thermoelectric devices. 相似文献
57.
Algorithms for Extracting Correct Critical Points and Constructing Topological Graphs from Discrete Geographical Elevation Data 总被引:12,自引:0,他引:12
Shigeo Takahashi Tetsuya Ikeda Yoshihisa Shinagawa Tosiyasu L. Kunii Minoru Ueda 《Computer Graphics Forum》1995,14(3):181-192
Researchers in the fields of computer graphics and geographical information systems (GISs) have extensively studied the methods of extracting terrain features such as peaks, pits, passes, ridges, and ravines from discrete elevation data. The existing techniques, however, do not guarantee the topological integrity of the extracted features because of their heuristic operations, which results in spurious features. Furthermore, there have been no algorithms for constructing topological graphs such as the surface network and the Reeb graph from the extracted peaks, pits, and passes. This paper presents new algorithms for extracting features and constructing the topological graphs using the features. Our algorithms enable us to extract correct terrain features; i.e., our method extracts the critical points that satisfy the Euler formula, which represents the topological invariant of smooth surfaces. This paper also provides an algorithm that converts the surface network to the Reeb graph for representing contour changes with respect to the height. The discrete elevation data used in this paper is a set of sample points on a terrain surface. Examples are presented to show that the algorithms also appeal to our visual cognition. 相似文献
58.
Tetsuya Yoshihisa Hiroto Daisuke Mitsuhisa Umpei 《Future Generation Computer Systems》2008,24(6):613-619
In this paper we present a master–worker type parallel method for finding several eigenvalues and eigenvectors of a generalized eigenvalue problem , where A and B are large sparse matrices. A moment-based method that finds all of the eigenvalues that lie inside a given domain is used. In this method, a small matrix pencil that has only the desired eigenvalues is derived by solving large sparse systems of linear equations constructed from A and B. Since these equations can be solved independently, we solve them on remote servers in parallel. This approach is suitable for master–worker programming models. We have implemented and tested the proposed method in a grid environment using a grid RPC (remote procedure call) system called OmniRPC. The performance of the method on PC clusters that were used over a wide-area network was evaluated. 相似文献
59.
Masao Shimizu Naoto Kudo Yoshinobu Nakajima Noboru Matsuo Yoshihisa Katsuragi Ichiro Tokimitsu Francisca Barceló 《Journal of the American Oil Chemists' Society》2008,85(7):629-633
Olive oils have a higher relative diacylglycerol (DAG) content than other plant oils. The lipase in olive fruits is involved
in DAG production and is directly related to the acidity of the olive oil. However, the lipase activity and positional selectivity
have not been clarified. To investigate the properties of olive fruit lipase, olive fruits of the Mission variety harvested
during mid-December of 2005 on Shodoshima Island (Japan) were stored at 20, 30 or 40 °C for 4 weeks. Changes in the acidity
and acylglycerol content of the oils extracted from the stored fruits were analyzed. The acidity and DAG content of the olive
oils increased due to triacylglycerol (TAG) hydrolysis during storage. sn-1,2-DAGs preferentially increased during the early stages of storage, indicating that the olive fruit lipase is enantioselective
for the sn-3 position, while non-enzymatic isomerization of sn-1,2-DAGs was observed throughout the entire duration of storage. Kinetic analysis revealed that the enantioselectivity of
olive fruit lipase for the sn-3 position was approximately four times greater than for the sn-1 position. The lipase was gradually inactivated at temperatures of 30 °C or higher, and the ratios of the rate constant
for inactivation to TAG hydrolysis at the sn-3 position was 0.2, 13, and 23 at 20, 30, and 40 °C, respectively. 相似文献
60.
Thin films of microcrystalline (CnH2n + 1NH3)2PbBr4 (n = 4, 5, 7 and 12) have been prepared by a modified spin-coating method, and the effect of the number of carbon atoms of the alkyl chain length (n) on optical properties has been investigated. Absorption spectra reveal that (CnH2n + 1NH3)2PbBr4 films show stable excitons with a binding energy of a few hundred meV. The excitonic structure of (CnH2n + 1NH3)2PbBr4 varies with the number of carbon atoms. The lowest-energy exciton splits into a few fine-structure levels at low temperature. (CnH2n + 1NH3)2PbBr4 films (n = 5, 7 and 12) show not only singlet excitons but also triplet excitons at low temperature, while (C4H9NH3)2PbBr4 films show only singlet excitons. The intersystem crossing from excited singlet state to triplet state plays an important role in the relaxation process of excitons. 相似文献