全文获取类型
收费全文 | 314篇 |
免费 | 12篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 43篇 |
金属工艺 | 5篇 |
机械仪表 | 5篇 |
建筑科学 | 29篇 |
矿业工程 | 2篇 |
能源动力 | 15篇 |
轻工业 | 15篇 |
无线电 | 29篇 |
一般工业技术 | 58篇 |
冶金工业 | 56篇 |
原子能技术 | 3篇 |
自动化技术 | 63篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 9篇 |
2016年 | 16篇 |
2015年 | 3篇 |
2014年 | 10篇 |
2013年 | 17篇 |
2012年 | 17篇 |
2011年 | 17篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 17篇 |
2007年 | 12篇 |
2006年 | 15篇 |
2005年 | 19篇 |
2004年 | 12篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 9篇 |
1997年 | 11篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有326条查询结果,搜索用时 31 毫秒
81.
Efficient topology optimization in MATLAB using 88 lines of code 总被引:4,自引:3,他引:1
Erik Andreassen Anders Clausen Mattias Schevenels Boyan S. Lazarov Ole Sigmund 《Structural and Multidisciplinary Optimization》2011,43(1):1-16
The paper presents an efficient 88 line MATLAB code for topology optimization. It has been developed using the 99 line code
presented by Sigmund (Struct Multidisc Optim 21(2):120–127, 2001) as a starting point. The original code has been extended by a density filter, and a considerable improvement in efficiency
has been achieved, mainly by preallocating arrays and vectorizing loops. A speed improvement with a factor of 100 is obtained
for a benchmark example with 7,500 elements. Moreover, the length of the code has been reduced to a mere 88 lines. These improvements
have been accomplished without sacrificing the readability of the code. The 88 line code can therefore be considered as a
valuable successor to the 99 line code, providing a practical instrument that may help to ease the learning curve for those
entering the field of topology optimization. The paper also discusses simple extensions of the basic code to include recent
PDE-based and black-and-white projection filtering methods. The complete 88 line code is included as an appendix and can be
downloaded from the web site . 相似文献
82.
Boyan S. Lazarov Mattias Schevenels Ole Sigmund 《Structural and Multidisciplinary Optimization》2012,46(4):597-612
The aim of this paper is to introduce the stochastic collocation methods in topology optimization for mechanical systems with material and geometric uncertainties. The random variations are modeled by a memory-less transformation of spatially varying Gaussian random fields which ensures their physical admissibility. The stochastic collocation method combined with the proposed material and geometry uncertainty models provides robust designs by utilizing already developed deterministic solvers. The computational cost is discussed in details and solutions to decrease it, like sparse grids and discretization refinement are proposed and demonstrated as well. The method is utilized in the design of compliant mechanisms. 相似文献
83.
Mattias Nordin Johann Galic' Per-Olof Gutman 《International Journal of Adaptive Control and Signal Processing》1997,11(1):49-63
Backlash is the most important non-linearity that limits the performance of speed control in industrial drives and is an important impediment to position control as well. A new simple model based on phase plane analysis is derived for an elastic shaft with internal damping connected to a backlash The model is extended to include the case of a so-called flexible coupling, where some of the backlash gap is filled with rubber. Extensive measurements on an industrial drive with a flexible coupling are compared with simulations and fit very well. With internal damping the classical dead-zone model gives an unphysical behaviour of the dynamics. However, the new model converges to the classical dead-zone model when the damping tends to zero. © 1997 by John Wiley & Sons, Ltd. 相似文献
84.
Prior work suggests that inhibition of the dorsal raphe nucleus (DRN) either during exposure to inescapable electric shock (IS) or during later behavioral testing might block the usual behavioral consequences of IS. The 5-HT1A agonist 8-OH-DPAT was microinjected into the region of the DRN either before exposure to IS or before testing for fear conditioning and escape learning conducted 24 hr later. IS potentiated fear conditioning and interfered with escape performance. These effects were completely prevented by intra-DRN administration of 8-OH-DPAT at either point. Low but not high systemic doses of 8-OH-DPAT had a similar effect, supporting the idea that the effective site of action is presynaptic. The relation between these data and other effects of 8-OH-DPAT is discussed. 相似文献
85.
86.
An analysis of measured field failure rates of printed circuit boards has been performed. The “part count” method currently used for reliability predictions was evaluated. A new model for electronic reliability prediction has been proposed. It uses statistics from board and system tests performed at the production plant and the number of conductive layers on the board. The report shows that there is a correlation between production test statistics and field performance, for high-volume boards. The proposed model shows that a high production test yield indicates high field reliability. This means that if actual production test results are poor, actions can be taken to improve reliability before numerous boards are delivered to customers. 相似文献
87.
An analytical model for the channel region in MOS-gated power transistors has been developed. The model takes into account the effect of substrate doping gradient on the threshold voltage of the transistor and it can be applied to lateral and vertical DMOS and IGBT transistor structures. The model has been tested by comparing the calculated I-V characteristics for an MOS structure having various doping gradients to the results from a 2-D device simulator.<> 相似文献
88.
89.
90.