全文获取类型
收费全文 | 822篇 |
免费 | 31篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 87篇 |
综合类 | 1篇 |
化学工业 | 196篇 |
金属工艺 | 20篇 |
机械仪表 | 35篇 |
建筑科学 | 28篇 |
能源动力 | 38篇 |
轻工业 | 83篇 |
无线电 | 74篇 |
一般工业技术 | 172篇 |
冶金工业 | 41篇 |
原子能技术 | 13篇 |
自动化技术 | 70篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 16篇 |
2020年 | 9篇 |
2019年 | 19篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 18篇 |
2015年 | 10篇 |
2014年 | 17篇 |
2013年 | 41篇 |
2012年 | 32篇 |
2011年 | 50篇 |
2010年 | 45篇 |
2009年 | 31篇 |
2008年 | 37篇 |
2007年 | 38篇 |
2006年 | 40篇 |
2005年 | 39篇 |
2004年 | 31篇 |
2003年 | 24篇 |
2002年 | 30篇 |
2001年 | 15篇 |
2000年 | 14篇 |
1999年 | 14篇 |
1998年 | 18篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 15篇 |
1994年 | 6篇 |
1993年 | 14篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 3篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 15篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 12篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 4篇 |
排序方式: 共有858条查询结果,搜索用时 31 毫秒
101.
Simulation of pyramid type three-roll bending process 总被引:2,自引:0,他引:2
A simulation of the deformation of a workpiece with a U-shaped cross section in a three-roll bending process is performed. Based on the properties of the workpiece, the distribution of curvature and bending moment are calculated in accordance with the displacement and the rotation of the rolls. The relationship between the position of the rolls and the final curvature of the workpiece is obtained. An experiment is performed and the accuracy of the simulation is confirmed. 相似文献
102.
Susumu Isaka Takeshi Yagisawa Tadashi Tokumasu Toshio Kase Shin-Ichi Menju 《Electrical Engineering in Japan》1996,116(6):72-82
In a three-phase, three-leg core of a core-type power transformer, the yokes are magnetically connected to all three phases so as to ease the flow of the magnetic flux (generally by means of lap joints of yokes and legs), and at the same time to smooth the magnetic flux between phase legs through yokes. It has generally been assumed that a split core with full separation at the center of the leg including yokes is unsuitable for use in power transformers owing to core losses, local heating, and noise resulting from the imbalance and distortion of magnetic flux, even though it can be used in distribution transformers with wound cores. But since the split core has many advantages from the manufacturing viewpoint, the magnetic characteristics of small core models were studied in detail. Studies with a full-scale 1500/3 MVA model transformer core indicate that the degradation of magnetic characteristics compares favorably with conventional cores. 相似文献
103.
Takashi Shinmoto Chiaki Kimura Ken Yamamoto Susumu Umeda 《Electrical Engineering in Japan》1996,116(5):75-84
The method for measuring insulation resistance by superimposing the dc voltage has potential for detecting the deterioration of cable insulations. The deterioration of cable insulations can be detected by measuring current which flows through a grounded shielding wire. However, the earth current also flows from the cable sheath into the grounding wire as noise. Thus, to assess the deterioration properly, it is necessary to separate the earth current from the total current. On the other hand, to improve detection sensitivity, it is desirable to superimpose the highest possible dc voltage. In this case, provision must be made so that there are no adverse effects on the GPT. The authors, placing special emphasis on the method of measuring high insulation resistance by configuring the bridge, have conducted an investigation on how to detect the insulation deterioration with high accuracy and sensitivity without impairing the functions of the GPT. The following issues were investigated and the results are reported in this paper: (1) It is possible to measure insulation resistance as high as 100,000 MΩ by superimposing 50-V dc through the GPT after cancelling the earth-current and by configuring a bridge for determining insulation resistance from voltage ratio. (2) Even if 50-V dc is superimposed through the GPT, it is possible to prevent the magnetic saturation of GPT if the current injected by such superimposition is limited (i.e., below max. 5 mA). (3) In lieu of a variable resistor, a variable dc voltage supply is employed in the bridge. The variable dc voltage supply requires no mechanically driven part, thus making it possible to realize a fully automatic monitoring system. 相似文献
104.
105.
Koichi Hatada Tatsuki Kitayama Shigeru Danjo Yutaka Tsubokura Heimei Yuki Kazuyuki Moriwaki Hiroaki Aritome Susumu Namba 《Polymer Bulletin》1983,10(1-2):45-50
Summary Polymer of α-substituted benzyl methacrylate was found to be used as a new type of positive electron-beam resist, which forms
methacrylic acid units in the polymer chain on the exposure to electron-beam and can be developed using alkaline solution
as a developer. The sensitivity was dependent on the bulkiness of the ester group and the number of ?-hydrogen atoms in the
ester group. The sensitivity and γ-value of atactic poly(α, α-dimethylbenzyl methacrylate) were improved by a factor of more
than three over poly (methyl methacrylate). 相似文献
106.
Compound classes in coal liquids were investigated by thin-layer chromatography coupled with a flame ionization detector (t.l.c.-f.i.d.). Individual t.l.c. peaks for coal liquids were identified as paraffins, aromatics, polar compounds and more strongly polar compounds or asphaltenes in order of increasing Rf values by comparison with specific compounds separated previously by conventional liquid chromatography. Concentrations of compound classes for a series of samples obtained by varying the hydrogenation time were estimated and good agreement was found with the results obtained by the USBM-API 60 liquid chromatography procedure. By using the t.l.c.-f.i.d. method, the relation of distribution of compound classes to the reaction conditions of coal hydrogenation could be derived quantitatively with relative ease. 相似文献
107.
Supachai Ngamsinlapasathian Sorapong Pavasupree Yoshikazu Suzuki Susumu Yoshikawa 《Solar Energy Materials & Solar Cells》2006,90(18-19):3187-3192
Nanocrystalline mesoporous titania was obtained by surfactant-assisted templating method using tetraisopropyl orthotitanate modified with acethylacetone and laurylamine hydrochloride as template. This material was applied for the electrode of dye-sensitized solar cell. The mesoporous TiO2 (MP-TiO2) cells exhibited higher short-circuit photocurrent density and solar energy conversion efficiency compared to P25 (a typical commercial titania powder) cells. The incident photon to current conversion efficiency spectrum of MP-TiO2 can be improved by using the cell made with 5% P25 additive. Double-layer titania cells were fabricated to further improve cell performance by increasing the film thickness and light scattering. The solar conversion efficiency up to 8.06% was obtained by using the double-layer titania cell sintered at 450 °C for 2 h. 相似文献
108.
Ichinose Susumu Matsuki Makoto Higuchi Kazuhito 《Industry Applications, IEEE Transactions on》1985,(1):47-52
A new solid-state scanning ink jet recording technique, called slit jet recording, is proposed. This technique uses a recording head with one slitlike ink-issuing opening having a number of recording electrodes arrayed along a horizontal scanning direction. The ink is emitted from the ink-issuing opening due to the electrical potential difference between a driven recording electrode and a counterelectrode located behind the recording paper. The ink strikes the paper and forms a recording dot. Many recording electrodes can be driven simultaneously by video signals which enhance the total copy recording speed over that for conventional techniques using a single nozzle. The head of this ink jet recording apparatus is remarkably simple in construction and can be fabricated without difficulty. Improvements in reliability and maintainability can also be expected, as the simple structure of the ink-issuing opening reduces clogging and facilitates easy cleaning as compared with other equipment having a large number of nozzles. The recording principle and characteristics and ink-issuing characteristics are described, and the results of a trial recording are presented. The results show that an ISO A4 size (210 mm x 297 mm) full-color copy can be recorded in about 30 s at an 8-dot/ mm rate. 相似文献
109.
110.
Susumu Onaka Satoshi Soeta Masaharu Kato Ryohei Tanaka 《Journal of Materials Science》1988,23(2):577-582
Bicrystals of CU-SiO2 dispersion-hardened alloys and of pure copper were tensile tested at various temperatures between 450 and 1050 K at a strain rate of 1.5 x 10–4 sec–1. In the case of pure copper bicrystals, elongation to fracture did not depend significantly on temperature and the fracture mode was invariably transgranular up to 850 K. On the other hand, the ductility of CU-SiO2 bicrystals decreased with increase in temperature and the transition in the fracture mode from transgranular to intergranular occurred at around 450 K. SiO2 particles on grain boundaries play an important role on intergranular fracture by suppressing grain-boundary sliding and also on the retardation of recrystallization during deformation. Two types of Cu-SiO2 bicrystals having different crystal orientation relationships show quite different deformation and fracture behaviour. This can be explained in terms of the contribution of lattice dislocations to the grain-boundary sliding. 相似文献