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231.
Coprecipitation of a proper amount of copper(II) sulfate with iron(III) sulfate on ultrafine silica gel by using an excess Na2CO3 resulted in a Fe-Cu/SiO2 catalyst with remarkably enhanced activity and selectivity for partial hydrogenation of phenylacetylene. The efficient elimination of water formed during the reduction of precursors much improved the activity. 相似文献
232.
Optical neural chips 总被引:1,自引:0,他引:1
An array of photodetectors, each having a variable sensitivity, forms the most important component of our two gallium arsenide chips. We designed the optical neurochip so that variable sensitivity photodiodes are monolithically integrated on top of an LED array, serving both as fast analog multipliers and as on-chip weight storage elements with learning capability. Our artificial retina device combines a VSPD array with a neural network for postprocessing, allowing us to perform fast, yet flexible, processing operations on projected images 相似文献
233.
Shigeru Sugiyama Yoshihisa Nitta Yukimi Furukawa Ai Itagaki Takuya Ehiro Keizo Nakagawa Masahiro Katoh Yuuki Katou Shuji Akihara Wataru Ninomiya 《化学与化工:英文版》2013,(11):1014-1020
The oxidative dehydrogenation of isobutane to isobutene was examined for the use in the preparation of FSM-16 and related compounds doped by chromium with expectations that a yield of isobutene of greater than 8% could be achieved. The activity depended on the molding procedure of the catalyst and the doping method of the chromium species. In the present study, 8.8% and 8.3% of the yield of isobutene were obtained at 0.75 h and 6 h on-stream for the catalyst (Cr-loading; 6.2 wt.%) molded using wet treatment hut not pressurization treatment, in which the chromium species were directly added into the aqueous solution containing raw FSM-16 (hydrated sodium silicate powder) at an initial stage of the catalyst preparation. The structure information was based on XRD (X-ray diffraction), the specific surface area was determined using a conventional BET (Brunauer-Emmett-Teller) nitrogen adsorption and the loading of chromium was estimated using ICP (inductively coupled plasma). All those parameters combined with the molding method indicated that the catalytic activity was more influenced by the loading of chromium into bulk but not on surface of the catalyst rather than by the hexagonal structure of FSM-16 and the surface area. 相似文献
234.
Wataru Nitta Keisuke Isogai Clemens Schlosser 《Journal of Nuclear Science and Technology》2013,50(5):712-719
Atmospheric 85Kr and 133Xe activity concentrations were determined from weekly air samples collected at Sapporo, Akita and Chiba, Japan, throughout 2011. The results demonstrated that the Fukushima Dai-ichi Nuclear Power Plant accident in early March 2011 resulted in high 133Xe activity concentrations as well as elevated levels of 85Kr activity; there was a striking increase in the concentrations of both isotopes over the week running from 14 to 22 March as the radioactive plume released from the plant was captured. At Chiba, following the accident, the 85Kr activity concentration increased from 1.38 to 17.7 Bq/m3, while the 133Xe levels increased from below the minimum detectable concentration (MDC ≤ 1.9 × 10?3 Bq/m3) to 1.3 × 103 Bq/m3. Conversely, at Sapporo and Akita, high 85Kr activity concentrations were not observed, due to differences in air transportation mechanisms based on wind directions. Duplicate samples were collected at Chiba to allow the simultaneous analyses of 85Kr and 133Xe at the Japan Chemical Analysis Center and the Bundesamt für Strahlenschutz in Germany and the results were in good agreement. The external effective radiation doses resulting from 85Kr and 133Xe releases following the accident were estimated to be approximately 7.0 × 10?3 and 1.3 μSv, respectively, based on the activity concentrations of these nuclides from March to June in 2011 at Chiba. 相似文献
235.
Shuhei Nitta Tomoyuki Takeguchi Nobuyuki Matsumoto Shigehide Kuhara Kenichi Yokoyama Rieko Ishimura Toshiaki Nitatori 《Magma (New York, N.Y.)》2013,26(5):451-461
Objectives
Automatic slice alignment is important for easier operation and shorter examination times in cardiac magnetic resonance imaging (MRI) examinations. We propose a new automatic slice alignment method for six cardiac planes (short-axis, vertical long-axis, horizontal long-axis, 4-chamber, 2-chamber, and 3-chamber views).Materials and methods
ECG-gated 2D steady-state free precession axial multislice images were acquired using a 1.5-T MRI scanner during a single breath-hold. The scanning time was set to <20 s in 23 volumes from 23 healthy volunteers. In this method, the positions of the mitral valve, cardiac apex, left ventricular outflow tract, tricuspid valve, anterior wall of the heart, and right ventricular corner are detected to determine the positions of six reference planes by combining knowledge-based recognition and image processing techniques. In order to evaluate the results of automatic slice alignment for the short-axis, 4-chamber, 2-chamber, and 3-chamber views, the angular and positional errors between the results obtained by our proposed method and by manual annotation were measured.Results
The average angular errors for the short-axis, 4-chamber, 2-chamber, and 3-chamber views were 3.05°, 4.52°, 7.28°, and 5.79°, respectively. The average positional errors for the short-axis (base), short-axis (apex), 4-chamber, 2-chamber, and 3-chamber views were 6.61°, 3.80°, 1.55°, 1.52°, and 1.48°, respectively.Conclusion
The experimental results showed that our proposed method can detect the cardiac planes quickly and accurately. Our method is therefore beneficial to both patients and operators. 相似文献236.
T Iwamoto A Fujie K Nitta S Hashimoto M Okuhara M Kohsaka 《Canadian Metallurgical Quarterly》1994,47(10):1092-1097
WF11899A, B and C, novel water-soluble lipopeptides related to the echinocandins, possess potent anti-Candida activities. The IC50s of the compounds against four clinical isolates of Candida albicans ranged from 0.004 to 0.03 microgram/ml by microbroth dilution assay. These compounds mildly suppressed the growth of Aspergillus fumigatus and A. niger. WF11899A, B and C showed a potent in vivo anti-Candida activity. Particularly, WF11899A was superior to cilofungin, and equal to fluconazole. 1,3-beta-glucan synthase was inhibited by these compounds at the IC50s of 0.7, 0.7 and 1.8 micrograms/ml for WF11899A, B and C, respectively. However, they hemolysed mouse red blood cells in vitro at the concentration of 62 micrograms/ml. 相似文献
237.
This paper describes the distributed microprocessor architecture used in the Electra IMS digital communication system. The system has been in service in the U.S. as of 1985. The system's maximum line size is 160, its maximum trunk size is 80, and it can accommodate both normal single-line telephones and proprietary digital telephones. Data switching can also be performed because of the PCM/ TDM architecture. The distributed architecture is composed of a system control (SCU) and six module control units (MCU), each MCU handles 32 ports of peripheral equipment.bullet The SCU and MCU's have a simplified common OS designed to handle the basic call processes.bullet The SCU executes line-state control, time-slot control, and systemfeature application.bullet The MCU executes peripheral-operation control and peripheral-status control. Software architecture is divided into small modules which represent each system function at the SCU, or each operating sequence at the MCU, so that addition or deletion of system features is very easy to implement. Hand-shaking belwccn the SCU and MCU's is controlled using a "message" which consists of several words. This architecture enables a nonsquare key telephone configuration, the building-block concept, and future system enhancement. 相似文献
238.
239.
240.
Akito Nitta Takashi Ogata Kazuo Kuwabara 《Fatigue & Fracture of Engineering Materials & Structures》1989,12(2):77-92
Abstract— In order to investigate the elevated-temperature low-cycle fatigue characteristics of Type 304 stainless steel under biaxial loading, strain-controlled push-pull and torsional fatigue tests were conducted at 550°C under proportional and nonproportional loading conditions with phase differences of 0, α/6, α/4, α/3 and α/2 between the applied sinusoidal axial and torsional strains. Based on the experimental results, this study presents a discussion on fracture mechanisms and failure criteria. In the case of proportional loading, the fracture mode was found, from fractographic observations, to be classified into either Mode I or Mode II, while the fractures were of mixed mode under nonproportional loading. However, failure lives under both the loading conditions could be correlated well in this study with the equivalent shear strain range, Δy, defined by extending the β -plane theory of Brown and Miller. The failure life under nonproportional loading could also be predicted by applying a strain-energy-based approach. 相似文献