全文获取类型
收费全文 | 899篇 |
免费 | 17篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 28篇 |
综合类 | 1篇 |
化学工业 | 118篇 |
金属工艺 | 15篇 |
机械仪表 | 11篇 |
建筑科学 | 16篇 |
能源动力 | 57篇 |
轻工业 | 71篇 |
无线电 | 155篇 |
一般工业技术 | 177篇 |
冶金工业 | 182篇 |
原子能技术 | 33篇 |
自动化技术 | 53篇 |
出版年
2023年 | 5篇 |
2021年 | 9篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 11篇 |
2014年 | 14篇 |
2013年 | 65篇 |
2012年 | 17篇 |
2011年 | 30篇 |
2010年 | 31篇 |
2009年 | 26篇 |
2008年 | 41篇 |
2007年 | 48篇 |
2006年 | 18篇 |
2005年 | 26篇 |
2004年 | 23篇 |
2003年 | 36篇 |
2002年 | 20篇 |
2001年 | 16篇 |
2000年 | 25篇 |
1999年 | 20篇 |
1998年 | 64篇 |
1997年 | 56篇 |
1996年 | 39篇 |
1995年 | 22篇 |
1994年 | 11篇 |
1993年 | 23篇 |
1992年 | 21篇 |
1991年 | 17篇 |
1990年 | 14篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 12篇 |
1986年 | 22篇 |
1985年 | 13篇 |
1984年 | 15篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 3篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1968年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有917条查询结果,搜索用时 0 毫秒
91.
Noda M. Matsue S. Sakai M. Sumitani K. Nakano H. Oku T. Makino H. Nishitani K. Otsubo M. 《Electron Devices, IEEE Transactions on》1992,39(3):494-499
The authors have realized 16-kb SRAMs with maximum address access time of less than 5 ns and typical power dissipation of less than 2 W at temperatures ranging from 25°C to 100°C. For the RAMs, they have developed a triple-level Au-based interconnection technology that reduces the wiring length and chip size of the SRAM so as to achieve high speed and high yield. Consequently, the wiring length and chip size are reduced to 69% and 58%, respectively, of those obtained by in previous work. The authors experimentally compared the delay time incurred by double-level interconnection and that by triple-level interconnection. This ratio is found to agree well with the simulated one by a model with distributed RC delay. After successfully suppressing Au hillock generation by lowering the process temperature, yield per wafer of 10% is obtained 相似文献
92.
The fabrication processings and the preliminary bias-temperature life tests for planar-type InGaAs/InP heterostructure avalanche photodiodes (HAPD's) made from VPE-grown wafers are presented. The plasma deposited SiNx passivation film showed a surface state density Nss of less than 1012cm-2. eV-1. An anomalous behavior of Cd diffusion velocity was observed in the process of the guard-ring formation. A Cr/Au p-side electrode made it possible to reduce the contact failure compared to an Au/Zn contact. Bias-temperature life tests were carried out at three temperature levels: 80, 120, and 180°C. Low-bias life tests (V_{R} = 10 V) were tried at first for the diodes without a guard-ring structure for times exceeding 10 000 h. The HAPD's with the guard-ring have been tested under the condition of high electric field (>4 times 10^{5} V/cm). The stable devices have been operating up to 6000 h under the high field condition even at 180°C. The HAPD's are still at the prototype stage. Thus, the test results are considered to be encouraging as to achieving highly reliable photodiodes. 相似文献
93.
Fumi Kojin Masanobu Mori Yumiko Noda Michio Inagaki 《Applied catalysis. B, Environmental》2008,78(3-4):202-209
Carbon-coated W18O49 powders were prepared from the mixture of para-ammonium tungstate with poly(vinyl alcohol) by heat treatment in inert atmosphere at a temperature between 750 and 900 °C for 1 h. The synthesized W18O49 crystals had prismatic morphology in small size, less than 0.5 μm in diameter and about 1 μm in length. Carbon-coated W18O49 was shown to have photoactivity under visible light irradiation by comparing the concentration changes of methylene blue, phenol and dimethylsulfoxide with time under the irradiation of visible light to that in the dark. Photoactivity of W18O49 was supposed to be due to the formation of OH radicals on the basis of the degradation of dimethylsulfoxide, its quantitative transformation to methanesulfonic acid. Carbon coating seemed to have various roles: to reduce WO3 to W18O49, to inhibit the sintering and crystal growth of W18O49 to keep them small size, and also to concentrate pollutants around W18O49 crystal by adsorption. 相似文献
94.
Monolithic integration of InGaAsP/InP distributed feedback laser and electroabsorption modulator by vapor phase epitaxy 总被引:2,自引:0,他引:2
Suzuki M. Noda Y. Tanaka H. Akiba S. Kushiro Y. Isshiki H. 《Lightwave Technology, Journal of》1987,5(9):1277-1285
Monolithic integration of a 1.55-μm InGaAsP/InP distributed feedback (DFB) laser and an electroabsorption (EA) modulator was studied. The difference between the lasing photon energy and the bandgap energy of the modulator waveguide was designed to be 30-40 meV, taking into account the linewidth-enhancement factor and the zero-bias absorption loss. The integrated devices were grown by three-step vapor phase epitaxy (VPE). The CW threshold current at 20°C of the DFB laser part with a buried heterostructure was 30-60 mA and the breakdown voltage of the modulator part with a strip-loaded stripe geometry was 20-40 V, and these values indicated satisfactory crystal quality in the VPE epitaxial layers. The operating voltage of the modulator to give on:off ratios of 10:1 and 100:1 was 1.5- 4 V and 2.5-6.5 V, respectively, depending on the length in the range200-500 mu m. A 3-dB bandwidth of about 2.5 GHz and a linewidth-enhancement factor of about 1.6 were obtained for the integrated modulator. 相似文献
95.
Sakai K. Miyai E. Sakaguchi T. Ohnishi D. Okano T. Noda S. 《Selected Areas in Communications, IEEE Journal on》2005,23(7):1335-1340
The possibility of single-mode oscillation over a large cavity area for photonic crystal lasers emitting at the photonic band edge has resulted in much interest in such materials for new forms of solid-state laser. In this paper, we measure the photonic bandstructure in our sample and identify the lasing band edge. By mapping out the bandstructure at the /spl Gamma/-point, we have observed fine structure at the band edge. The experimental results are in good agreement with the theoretically predicted bandstructure. Above threshold, we observe a lasing peak at 965 nm at one of the band edges. The far-field distribution of the laser is measured, showing an annular profile and azimuthal polarization. Calculations on the far-field distribution at the lasing band edge suggest the annular profile is due to an anti-symmetric resonant mode. 相似文献
96.
97.
Tsugaru K. Sugimoto Y. Noda M. Ito T. Suwa Y. 《Solid-State Circuits, IEEE Journal of》1990,25(3):653-659
A +5-V single-power-supply 10-b video BiCMOS sample-and-hold IC is described. Video speed, low power, and 10-b accuracy sample-and-hold operation have been achieved using a complementary connected buffer format sample switch. A high-speed p-n-p transistor used in the sample switch is formed by a combination of n-p-n and PMOS transistors. The sample-and-hold operation is accomplished by feeding back the hold capacitor voltage to the sample switch inputs, so that the inputs transfer symmetrically for the hold capacitor voltage at any input level. The sample-and-hold IC has been implemented in 1.2-μm BiCMOS technology and evaluated. The following results have been obtained: 185-MHz 3-dB bandwidth at 22-pF hold capacitor, 63-dB signal-to-noise ratio at 8-MHz full-scale input, 20-ns acquisition time at 1-V step input, 15-ns switch setting time, and 0.1% linearity error. Power dissipation is 150 mW 相似文献
98.
Nao-Aki Noda Akifumi Inoue Masato Nagawa Fumitaka Shiraishi 《International Journal of Pressure Vessels and Piping》2002,79(12):807-818
This paper deals with a new seal system between flange joints without using a gasket. This gasketless flange includes a groove and an annular lip that is machined in one of the flange rings which when removed being in contact with the other flange to form a seal line when the flanges are assembled. In this study, firstly, fundamental dimensions are examined for unplasticized polyvinyl chloride (PVC-U JIS) to obtain the best sealing performance. Then, the effects of material difference and flange nominal size upon the sealing performance of the new gasketless flange are investigated for two types of materials, 0.25% carbon steel (S25C JIS) and PVC-U. It is found that the critical internal pressure at which leakage appears is mainly controlled by the maximum stress at the annular lip for each material even if the flange nominal sizes are different. The gasketless flange made by PVC-U shows the higher critical internal pressure compared with the case of S25C if the same clamping forces are applied. The effect of stress relaxation for PVC-U on the sealing performance is also considered. Then, it may be concluded that this PVC-U gasketless flange as well as S25C has good sealing performance. 相似文献
99.
Hiroaki Ishikawa Tetsuro Ogushi Takehide Nomura Takeshi Iwakami Hiroyuki Noda Takahiro Yabe 《亚洲传热研究》2007,36(3):143-157
High‐powered satellites need larger heat rejection areas. A deployable radiator is one of the key technologies for a high‐powered satellite bus. A Reservoir Embedded Loop Heat Pipe (RELHP) is a two‐phase heat transfer device that constitutes a deployable radiator. RELHP has an evaporator core which is used as a liquid reservoir to enhance operational reliability. This paper presents the heat transport characteristics of a RELHP under changing evaporator orientation against gravity and charged ammonia weight by experiment and calculation. Liquid slug position in the reservoir has a great influence on heat transport characteristics, caused by changing heat transfer coefficients between returned liquid into the evaporator and vapor in the reservoir. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(3): 143– 157, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20150 相似文献
100.
H. Tatsuno W. B. Doriese D. A. Bennett C. Curceanu J. W. Fowler J. Gard F. P. Gustafsson T. Hashimoto R. S. Hayano J. P. Hays-Wehle G. C. Hilton M. Iliescu S. Ishimoto K. Itahashi M. Iwasaki K. Kuwabara Y. Ma J. Marton H. Noda G. C. O’Neil S. Okada H. Outa C. D. Reintsema M. Sato D. R. Schmidt H. Shi K. Suzuki T. Suzuki J. Uhlig J. N. Ullom E. Widmann S. Yamada J. Zmeskal D. S. Swetz 《Journal of Low Temperature Physics》2016,184(3-4):930-937