全文获取类型
收费全文 | 644篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 83篇 |
金属工艺 | 5篇 |
机械仪表 | 12篇 |
建筑科学 | 27篇 |
矿业工程 | 1篇 |
能源动力 | 5篇 |
轻工业 | 59篇 |
水利工程 | 18篇 |
石油天然气 | 1篇 |
无线电 | 43篇 |
一般工业技术 | 83篇 |
冶金工业 | 227篇 |
原子能技术 | 2篇 |
自动化技术 | 85篇 |
出版年
2023年 | 3篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 9篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 19篇 |
2012年 | 12篇 |
2011年 | 21篇 |
2010年 | 19篇 |
2009年 | 19篇 |
2008年 | 23篇 |
2007年 | 31篇 |
2006年 | 30篇 |
2005年 | 15篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 15篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1998年 | 54篇 |
1997年 | 45篇 |
1996年 | 26篇 |
1995年 | 20篇 |
1994年 | 17篇 |
1993年 | 22篇 |
1992年 | 22篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1973年 | 5篇 |
1971年 | 5篇 |
1961年 | 2篇 |
1930年 | 2篇 |
1927年 | 2篇 |
排序方式: 共有656条查询结果,搜索用时 125 毫秒
1.
Presented here are details of the development of a novel membrane integrated circuit (IC) probe card structure based on microsystems technology. The device design allows probing of both solder bumps and pads. A self-limiting sensor was integrated to prolong device lifetime. Comparison with and discussion of the use of modelling is made. Possible enhancements to the probing structure are discussed to improve alignment and measurements. Also shown is data using our microsystems probe card to access a simple IC device. Our device has a contact resistance of less than 0.5 Ω for a force of 0.004 N. A method to implement our probing structure for commercial application and the potential developments which can be made to improve its ease of use are then discussed. 相似文献
2.
3.
JH Winstanley SJ Leinster TG Cooke BR Westley AM Platt-Higgins PS Rudland 《Canadian Metallurgical Quarterly》1993,67(4):767-772
The expression of the protease cathepsin-D has been evaluated using an immunohistochemical technique with a polyclonal antibody in paraffin-embedded tissue from 359 patients treated between the years 1975-1981 for Stage I and II breast cancer. One hundred and twenty seven patients (35%) have strongly positive, granular staining, 138 (38%) are intermediately stained in the cytoplasm, and in 94 (26%) no staining is observed. There is a strong positive association between expression of cathepsin-D and the presence of tumour in axillary lymph nodes (P < 0.006). Expression of the protease is associated with significantly poorer survival of patients in univariate analysis (P = 0.025); however, this is not independent of other tumour variables. 相似文献
4.
5.
6.
Kikushima K. Whitley T. Cooke R. Stalley K. Fake M. Lawrence E. 《Electronics letters》1994,30(17):1431-1432
The authors report the first use of a praseodymium-doped fluoride fibre amplifier (PDFFA) in a 24 TV channel FM-SCM transmission experiment. Twenty-four analogue FM-SCM-TV channels were amplified by a PDFFA without any observable degradation in picture quality. By using a single PDFFA as a post-amplifier, transmission over 104 km of `standard' 1.3 μm optimised fibre was demonstrated with a total loss budget of 45 dB. By using the same PDFFA as an inline amplifier, a loss budget of 53 dB was achieved 相似文献
7.
8.
9.
Cooke S.J. Chia-Lie Chang Antonsen T.M. Jr. Chernin D.P. Levush B. 《Electron Devices, IEEE Transactions on》2005,52(5):764-773
We describe a new model for calculating the ac space charge in a linear-beam traveling wave tube (TWT) large-signal simulation code when the true three-dimensional (3-D) geometry of the interaction circuit is taken into account. We use the 3-D electromagnetic simulation code CTLSS to characterize the ac space charge fields generated by a set of test currents placed inside the periodic interaction structure. This information, expressed in matrix form, is used by the large-signal simulation codes CHRISTINE-1D and CHRISTINE-3D to compute self-consistently the additional space charge field terms due to the structure in response to the beam evolution during the simulation. We present the formulation, and describe the implementation in both CTLSS and the large-signal codes. We validate the model by comparison with the analytical sheath helix model, and evaluate the importance of including this correction for modeling a number of helix and coupled-cavity TWT devices. 相似文献
10.
Roger M. Cooke 《Reliability Engineering & System Safety》1996,51(2):209-223
Models for analyzing dependent competing risk data are presented. These models are designed to represent interactions of critical failure and maintenance mechanisms responsible for intercepting incipient and degraded failures, and they are fashioned such that the (constant) critical failure rate is identifiable from dependent competing risk data. Uncertainty bounds for the critical failure rate which take modeling uncertainty and statistical fluctuations into account are given. 相似文献