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141.
Yusuke Wakikawa Tadaaki Ikoma Yohei Yamamoto Takanori Fukushima Takuzo Aida 《Synthetic Metals》2010,160(3-4):275-279
By means of the integral mode time-of-flight measurement of the drift motion of the photoinjected charge at room temperature, we observed magnetic field effect (MFE) on the photocharge in self-assembled nanotube of hexabenzocoronene (HBC) at the configurations where the magnetic field is parallel and perpendicular to the electric field. The detected MFEs are interpreted in terms of two mechanisms that are caused by the fast charge transportation (Hall effect) and the spin selective recombination (electron–hole (e–h) pair mechanism). A high mobility in the nanotubes of π-stacked HBC was implied from the Hall data. The time dependence of the low field MFE due to the e–h pair mechanism clarified the recombination from both the singlet and triplet e–h pairs with the initial rate of ~108 s?1. 相似文献
142.
Kenji Shimomura Kazuaki Akasaka Arata Yajima Takanori Mimura Shunsuke Yajima Kanju Ohsawa 《Journal of chemical ecology》2010,36(9):955-965
Callosobruchus analis (Coleoptera: Chrysomelidae: Bruchinae), found throughout tropical Asia and Africa, is a pest of stored legumes. Previous
work has shown that females of this species produce a contact sex pheromone that elicits copulatory behavior in males. Comparisons
of copulatory activity between any two of four congeneric species suggest that the contact sex pheromones are species specific.
In laboratory bioassays, male C. analis exhibited copulatory behavior to a female dummy to which a crude extract of virgin females was applied. The extract had been
collected by a filter paper method and was purified by acid–base partition and chromatographic techniques. Gas chromatography-mass
spectrometry (GC-MS) analyses of active fractions revealed that the active compounds were 2,6-dimethyloctane-1,8-dioic acid
(1) and callosobruchusic acid, (E)-3,7-dimethyl-2-octene-1,8-dioic acid (2), previously identified as contact sex pheromones of Callosobruchus maculatus (F.) and C. chinensis (L.), respectively. The stereoisomeric and chemical compositions were determined by the 2D-HPLC-Ohrui-Akasaka method as (2S,6R)-1:(S)-2 = 1.8:1, which meant that both compounds in C. analis were stereochemically pure, unlike the case of C. maculatus and C. chinensis. An examination of the influence of synthetic pheromone compounds on male copulatory activity revealed that (2S,6R)-1 is the main component, and that (S)-2 has an additive effect. In the examination of the stereochemistry-activity relationship, no copulatory behavior was elicited
by (2R,6S)-1, and, furthermore, the enantiomer significantly masked the pheromonal activity of (2S,6R)-1. Glass rod dummy assays also suggested the presence of synergists. These results could elucidate the specificity of mate
recognition in C. analis. 相似文献
143.
X. J. Liu C. P. Wang I. Ohnuma R. Kainuma K. Ishida 《Journal of Phase Equilibria and Diffusion》2000,21(5):432-442
Thermodynamic assessments have been made for the Cu-Sb and Sb-Zn binary systems by means of the CALPHAD technique. The Gibbs
energies of the liquid, bcc, and fcc phases are described by a substitution solution model and a Redlich-Kister formalism.
All of the compounds were treated as stoichiometric compounds. Moreover, the liquidus temperatures of the Zn-rich portion
in the Sb-Zn system were measured to check the unusual shape reported by previous work. It was confirmed that the liquidus
line is not peculiar but smooth. A consistent set of the thermodynamic parameters was optimized to obtain a better fit between
calculated results and experimental data including phase diagram and thermodynamic quantities. 相似文献
144.
145.
Yosuke Matsuo Yusuke Fujita Sachiko Ohnishi Takashi Tanaka Hideaki Hirabaru Takanori Kai Hiroshi Sakaida Shoko Nishizono Isao Kouno 《Food chemistry》2010
Chemical constituents of the leaves of rabbiteye blueberry (Vaccinium ashei READE) were investigated in detail. The major phenolic components were caffeoyl quinic acids, flavonol glycosides, flavan-3-ols and proanthocyanidins. Catechins and proanthocyanidins having additional phenylpropanoid units, such as cinchonains, kandelins and mururins, characterised the polyphenols of this plant. Among them, vaccinin A, an isomer of mururin A, was found to be a new compound, and the structure was characterised by spectroscopic methods. The most abundant polyphenols (11.3% of freeze-dried leaves) were oligomeric proanthocyanidins. Thiol degradation with mercaptoethanol indicated that the polymer was constituted of (+)-catechin and (−)-epicatechin as the terminal units and (−)-epicatechin, procyanidin A-2, and cinchonains Ia and Ib as the extension units. Mass spectral analysis suggested the presence of at least dodecamers with A-type linkages and phenylpropanoid moieties. 相似文献
146.
Zbigniew Oksiuta Pawel Kozikowski Malgorzata Lewandowska Masato Ohnuma Koppoju Suresh Krzysztof J. Kurzydlowski 《Journal of Materials Science》2013,48(13):4620-4625
In this study, the stability of grain size and oxide nanoparticles in the ODS steel upon annealing at high temperature (650–1350 °C) has been evaluated. The ODS Fe–Cr–W–Ti–Y2O3 steel has been manufactured by powder metallurgy, consolidated by hot isostatic pressing and processed by hydrostatic extrusion. Such a processing brings about ultrafine grain structure reinforced with oxide nanoparticles (few nm in diameter) and results in superior mechanical properties. The stability of nano-oxides has been analyzed by small angle X-ray scattering together with transmission electron microscopy. The results obtained revealed excellent thermal stability of ultrafine grained ODS ferritic steel, which was attributed to the resistance of oxides against coarsening. 相似文献
147.
Cormac J. Byrne Morten Eldrup Masato Ohnuma Rasmus S. Eriksen 《Journal of Materials Processing Technology》2010,210(11):1419-1428
Bulk metallic glasses have enormous potential for use in small-scale devices such as MEMS and biomedical components. Thermoplastic forging of free standing components poses challenges unlike those seen when forging crystalline materials. Central to these challenges is the simultaneous advantage/disadvantage that BMGs flow readily into small features and asperities in the dies and molds. Whilst useful for replicating patterned surfaces, this quite often makes non-destructive removal of components quite difficult, with disproportionate extraction forces and specialized tools required to overcome friction and mechanical locking. Several solutions to this extraction problem were explored, including high temperature extraction, lubrication and the use of materials with low coefficients of thermal expansion (CTE) as die/mold materials. We show that the use of appropriately chosen low CTE die materials offers a superior method to remove BMG components from dies/molds at room temperature. The criteria for selecting the appropriate die material, cavity size and extraction temperatures are outlined. 相似文献
148.
149.
Yoshikazu Takaku Komei Makino Keita Watanabe Ikuo Ohnuma Ryosuke Kainuma Yasushi Yamada Yuji Yagi Ikuo Nakagawa Takashi Atsumi Kiyohito Ishida 《Journal of Electronic Materials》2009,38(1):54-60
The Zn-Al(-Cu) eutectic alloys (melting point 381°C) are candidates for use as Pb-free high-temperature solders as a substitute
for Pb-based solders, which are suitable for severe working environments such as the engine room of hybrid vehicles equipped
with an inverter system as well as a heat engine. In this study, the interfacial reaction between Zn-Al(-Cu) alloys and the
Ni substrate during soldering, aging, and thermal cycling was investigated. Semiconductor chips and Ni substrates were soldered
with Zn-Al(-Cu) alloys at various temperatures under a nitrogen atmosphere. The soldered assemblies were then heat-treated
at 200°C and 300°C to examine the microstructural evolution at the soldered interface. The effect of severe thermal cycles
between −40°C and 250°C in air on the microstructure and fracture behavior at the solder joint was investigated. Even after
a 1000-cycle test, the thickness of the Al3Ni2 layer formed at the interface between the Zn-Al-based solder and the Ni substrate, which is responsible for the damage of
the soldered assemblies, was quite small. 相似文献
150.
Eva Hemmer Hiroyuki Takeshita Tomoyoshi Yamano Takanori Fujiki Yvonne Kohl Karin L?w Nallusamy Venkatachalam Hiroshi Hyodo Hidehiro Kishimoto Kohei Soga 《Journal of materials science. Materials in medicine》2012,23(10):2399-2412
The use of an “over 1000-nm near-infrared (NIR) in vivo fluorescence bioimaging” system based on lanthanide containing inorganic nanostructures emitting in the visible and NIR range under 980-nm excitation is proposed. It may overcome problems of currently used biomarkers including color fading, phototoxicity and scattering. Gd2O3:Er3+,Yb3+ nanoparticles and nanorods showing upconversion and NIR emission are synthesized and their cytotoxic behavior is investigated by incubation with B-cell hybridomas and macrophages. Surface modification with PEG-b-PAAc provides the necessary chemical durability reducing the release of toxic Gd3+ ions. NIR fluorescence microscopy is used to investigate the suitability of the nanostructures as NIR–NIR biomarkers. The in vitro uptake of bare and modified nanostructures by macrophages is investigated by confocal laser scanning microscopy. In vivo investigations revealed nanostructures in liver, lung, kidneys and spleen a few hours after injection into mice, while most of the nanostructures have been removed from the body after 24?h. 相似文献