全文获取类型
收费全文 | 634篇 |
免费 | 16篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 92篇 |
化学工业 | 136篇 |
金属工艺 | 10篇 |
机械仪表 | 8篇 |
建筑科学 | 9篇 |
能源动力 | 27篇 |
轻工业 | 28篇 |
水利工程 | 5篇 |
无线电 | 80篇 |
一般工业技术 | 128篇 |
冶金工业 | 82篇 |
原子能技术 | 20篇 |
自动化技术 | 28篇 |
出版年
2022年 | 4篇 |
2021年 | 7篇 |
2019年 | 6篇 |
2018年 | 11篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 28篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 23篇 |
2009年 | 19篇 |
2008年 | 19篇 |
2007年 | 38篇 |
2006年 | 27篇 |
2005年 | 22篇 |
2004年 | 12篇 |
2003年 | 20篇 |
2002年 | 16篇 |
2001年 | 14篇 |
2000年 | 19篇 |
1999年 | 15篇 |
1998年 | 46篇 |
1997年 | 24篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 14篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 15篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 9篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1972年 | 5篇 |
1970年 | 4篇 |
排序方式: 共有653条查询结果,搜索用时 15 毫秒
1.
Watanabe H. Komori J. Higashitani K. Sekine M. Koyama H. 《Semiconductor Manufacturing, IEEE Transactions on》1997,10(2):228-232
A novel monitoring method for plasma-charging damage is proposed. This method performs a quick and accurate evaluation using antenna PMOSFET. It was found that not only hot-carrier (HC) lifetime but transistor parameters such as initial gate current and substrate current were changed according to the degree of plasma-charging damage. However, the present work suggests that monitoring the shift of drain current after a few seconds of HC stress is a more accurate method to indicate plasma-charging damage. The monitoring method using the present test structure is demonstrated to be useful for realizing highly reliable devices 相似文献
2.
3.
Iwao Shimizu Yuji Naito Iwao Yamaguchi Katsuyuki Kaiho Hitoshi Mizoguchi Satoru Yanabu 《Electrical Engineering in Japan》2008,164(1):52-61
Using conventional high‐temperature superconducting wire, a model superconducting fault current limiter (SFCL) is made and tested. Solenoid coil using Bi2223 silver sheath wire is so made that inductance is as small as possible and a vacuum interrupter is connected in series to it. A conventional reactor coil is connected in parallel. When the fault current flows in this equipment, superconducting wire is quenched and current is transferred into the parallel coil because of voltage drop of superconducting wire. This large current in parallel coil actuates magnetic repulsion mechanism of vacuum interrupter. Due to opening of vacuum interrupter, the current in superconducting wire is broken. By using this equipment, current flow time in superconducting wire can be easily minimized. On the other hand, the fault current is also easily limited by large reactance of parallel coil. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(1): 52–61, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20315 相似文献
4.
New technologies such as power electronics have made it possible to change continuously the impedance of a power system not only to control power flow but also to enhance stability. A power system incorporating a variable impedance apparatus such as a variable series capacitor (VSrC) and high-speed phase shifter (HSPS) is called VIPS (Variable Impedance Power System) by the authors. This paper proposes a novel control method of VIPS apparatus such as VSrC and HSPS installed at an interconnecting point for stabilizing inter-area unstable and/or oscillatory modes. The proposed design method of the control system is a kind of hierarchical decentralized control method of a large-scale power system based on a Lyapunov function. Under the proposed control scheme, each subsystem can be stabilized independently by local controllers such as AVR, speed governor and PSS, and then the whole interconnected system can be stabilized by VIPS apparatus taking into account interactions between subsystems. The effectiveness and robustness of the VIPS apparatus control are shown by numerical examples with model systems including a large-scale power system. 相似文献
5.
K Yoshida Y Takamatsu Y Adachi M Kishi H Sekine T Shigematsu 《Canadian Metallurgical Quarterly》1996,37(2):55-62
Endoglucanase production was measured in culture filtrates of four species of Saccobolus growing in media containing glucose or crystalline cellulose as the only carbon sources. Enzyme activity was four to seven times higher in the presence of cellulose than glucose. S. saccoboloides showed maximal growth and enzyme production. The extracellular proteins secreted during growth on cellulose were separated by polyacrylamide gel electrophoresis and stained for proteins. A zymogram technique was used to visualize bands with endoglucanase activity. The four species showed different protein and isoenzyme patterns. 相似文献
6.
D. C. Kim S. Sayama M. Sekine 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(9):1499-1508
Sea clutter was measured using a millimeter wave radar with a frequency of 34.86GHz and pulse length of 30ns. A car carrier ship target was embedded in sea clutter. It has been discovered that target pulse-to-pulse fluctuations obey a Weibull distribution and sea clutter obey a Rayleigh distribution. We obtained target to clutter ratio improvement of 23.8dB by applying the cell average LOG/CFAR techniques. The computer simulation has been made to evaluate the detection probability and the false alarm probability. The simulation result was in good agreement with the observed data. 相似文献
7.
Mikio Miyake Katsuyuki Takahashi Jun Higashine Masakatsu Nomura 《Fuel Processing Technology》1992,30(3):205-213
A series of mixtures of Japanese subbituminous Taiheiyo coal and Athabasca oil sand bitumen (AOB) with various coal concentrations (0–100 wt%) was coprocessed in a 70 ml autoclave at 420°C for 1 h in the presence of H2 (50 kg/cm2 at room temperature) and sulfided Ni---Mo/Al2O2 catalyst. The mixture containing 2 wt% coal produced the largest amount of hexane soluble fraction (HS) and the smallest amount of benzene insoluble fraction (BI). Thus, a synergistic liquid production occurred for this mixture with 2 wt% coal by suppressing the retrogressive reactions which proceeded for pure AOB. The HS obtained from mixtures with 2–30 wt% showed higher H/C ratios and lower heteroatom contents than those obtained from pure AOB and the mixtures with more than 30 wt% coal. The amounts of transferable hydrogen contained in the mixtures were estimated using anthracene as a hydrogen acceptor. The mixtures with 2–10 wt% coal contained higher amounts of donor hydrogen than pure AOB. The HS yield from the various mixtures was correlated with the amount of donor hydrogens contained in the mixtures, except for the mixture with 10 wt% coal. Thus, the important factor which results in synergism is suggested to be the amount of donor hydrogens contained in the feed mixtures. 相似文献
8.
A superconductor/semimetal/superconductor (S/SM/S) Josephson junction has been developed. We have used an alloy of Pb1–x
Bi
x
(0x 0.6) as the superconductor and Bi as the semimetal. By irradiating at X-band microwave of 10 GHz, Shapiro steps were observed for various bismuth barrier thicknesses inÅ and bismuth weight ratiosx. Finally, we obtained the empirical relationship for barrier thickness, below which microwaves could be detected for various bismuth weight ratiosx at the temperature of 4.2 K. 相似文献
9.
Summary Polysilanes with an optically active alkoxy group, i.e., (S)-(+)-2-butoxy, (R)-(-)-2-butoxy, (S)-(-)-2-methyl-1-butoxy, and (S)-(+)-3,7-dimethyl-1-octoxy, at the terminal positions, the chiral carbon centers of which were located at the α, β, and γ
positions relative to the oxygen, respectively, were prepared, and the effect of the position of chiral center of the terminal
optically active group on the induction of optical activity in polysilanes was investigated. The circular dichroism (CD) spectra
of these polymers showed positive Cotton signals around 340 nm at temperatures below -20 °C, but the intensities were small,
indicating that the optically active groups at the terminal positions have some ability, albeit small, to induce optical activity
to the polysilanes. Further, the optically active (S)-(+)-2-butoxy and (R)-(-)-2-butoxy groups did not control the helical sense direction of the polymers, despite the different chiral stimuli from
the 2-butoxy groups introduced to the terminal positions. To control the helical structure of polysilanes by the use of optically
active terminal groups, appropriate optically active groups are required. 相似文献
10.
Dimethylsiloxane-tetramethyl-p-silphenylenesiloxane-dimethylsiloxane (DMS-TMPS-DMS) triblock copolymer was synthesized by employing living anionic polymerization of hexamethylcyclotrisiloxane (D3). Two synthetic methods were carried out for the polymerization. One of those methods was the anionic polymerization of D3 initiated at the silanolate anion which was prepared from the terminal hydroxyl group of silanol-terminated TMPS prepolymer by reaction with n-butyllithium (method 1). The other was the coupling reaction of vinyl-terminated TMPS prepolymer with hydrosilyl-terminated DMS prepolymer obtained from the anionic polymerization of D3 by using diphenylmethylsilanolate anion as initiator (method 2). In method 1, DMS contents of the copolymers ranged from 25.8 to 72.5 wt% and the values agreed with the ratio of D3 to TMPS prepolymer. The weight-average molecular weights ranged from 1.36×104 to 19.4×104 and were close to the predicted values calculated from the of the TMPS prepolymer and the amount of D3 added. In the case of method 2, weight-average molecular weights ranged from 19.5×104 to 24.2×104. The high molecular weight copolymer could thus be obtained by method 2. Intrinsic viscosity values of the triblock copolymers agreed with calculated values obtained by considering the copolymer as a binary mixture of these homopolymers. Differential scanning calorimetry and thermogravimetry were carried out on the triblock copolymers. The equilibrium melting temperatures of each of the copolymers were very close to that of poly-TMPS (160°C). The glass transition temperature and heat of fusion were decreased as the DMS content was increased. The thermogravimetric curves for the copolymers indicated that the thermal stability of the triblock copolymer was intermediate between the DMS and TMPS homopolymers. 相似文献