全文获取类型
收费全文 | 662篇 |
免费 | 20篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 82篇 |
综合类 | 1篇 |
化学工业 | 138篇 |
金属工艺 | 9篇 |
机械仪表 | 8篇 |
建筑科学 | 15篇 |
能源动力 | 28篇 |
轻工业 | 26篇 |
水利工程 | 7篇 |
无线电 | 73篇 |
一般工业技术 | 144篇 |
冶金工业 | 107篇 |
原子能技术 | 20篇 |
自动化技术 | 25篇 |
出版年
2023年 | 3篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2015年 | 9篇 |
2014年 | 18篇 |
2013年 | 31篇 |
2012年 | 21篇 |
2011年 | 18篇 |
2010年 | 26篇 |
2009年 | 20篇 |
2008年 | 24篇 |
2007年 | 34篇 |
2006年 | 27篇 |
2005年 | 16篇 |
2004年 | 16篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 11篇 |
2000年 | 19篇 |
1999年 | 19篇 |
1998年 | 53篇 |
1997年 | 30篇 |
1996年 | 21篇 |
1995年 | 12篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 12篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 17篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1967年 | 1篇 |
排序方式: 共有683条查询结果,搜索用时 15 毫秒
1.
The performance of surface ionic conduction single chamber fuel cell (SIC‐SCFC) prepared by the sol gel method was studied on electric characteristics due to the differences of the operating temperature and humidity, the electrode distance and electrolyte film depth, and multiple cells with the series and parallel connections. The SIC–SCFC was arranged the both anode of Pt and cathode of Au on the boehmite electrolyte. The open circuit voltage (OCV) of single cell achieved a maximum of 530mV in the dry gas mixtures of O2/H2=50% in room temperature operation, and but it became decrease as over 60%. The OCV was maintained the constant value between operating temperatures of 30°C to 80°C, and but it was decreased sharply at over 90°C because a humidity on the cell became lower as increasing operating temperature. Then, the cell property was improved to 120°C by adding to the humidity of 70% using a humidifier. The electrode distance and the electrolyte film depth of SIC‐SCFC found to be contributed to the reductions of the cell resistance and the surface roughness on the electrode, respectively. Moreover, the power property of SIC‐SCFC was significantly improved by cell stacks comprised of the series or parallel connection of a cell. 相似文献
2.
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
3.
4.
Akiyoshi Wakatani 《Parallel Computing》2004,30(12):1345-1359
It is hard to implement the ADI method in an efficient way on distributed-memory parallel computers. We propose “P-scheme” which parallelizes a tridiagonal linear system of equations for the ADI method, but its effectiveness is limited to the cases where the problem size is large enough mainly because of the communication cost of the propagation phase of the scheme.
In order to overcome this difficulty, we propose an improved version of the P-scheme with “message vectorization” which aggregates several communication messages into one and alleviates the communication cost. Also we evaluate the effectiveness of message vectorization for the ADI method and show that the improved version of the P-scheme works well even for smaller problems and linear and super-linear speedups can be achieved for 8194 × 8194 and 16,386 × 16,386 problems, respectively. 相似文献
5.
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
6.
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
7.
Tests and theoretical analysis on the maximum strength of high strength bolted tension flanges joining square hollow section members have been carried out. Yield line theory has been applied in a similar way to that presented in a previous paper. Correlation between test results and theoretical predictions is quite satisfactory. Based on this study, a simple design formula has been proposed. 相似文献
8.
氧浓度对近临界水中纤维素分解的影响 总被引:3,自引:0,他引:3
研究了不同初始氧浓度对纤维素在近临界水中分解的影响,实验结果表明,氧浓度显著地影响产物总碳收支平衡,液相不同组分的收率、气体的产量以及气相产物的组成,微量氧对产物总碳收支平衡影响不大,而对液相不同组分的收率有一定的影响。从实验结果可以看出,离子型反应机理在纤维素水解的第一步中起主导作用。而单糖的进一步分解是一个以自由基反应机理为主的过程。 相似文献
9.
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
10.
Solving regularized least squares with qualitatively controlled adaptive cross‐approximated matrices
The adaptive cross‐approximation (ACA) technique is applied to accelerating an inverse‐problem solver that estimates charge distribution on a dielectric spacer. The ACA generates an approximated system‐matrix that enables us to carry out high‐speed inverse calculation. We designed an approximation procedure based on ACA with some additional concepts, that is, (a) partitioning of matrix based on algebraic information, (b) approximation quality control based on matrix norms, and so on. The tested solver (LSQR for regularized least squares) with ACA demonstrates about 10 times faster performance than that without ACA. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(3): 10–18, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20326 相似文献