全文获取类型
收费全文 | 9785篇 |
免费 | 1252篇 |
国内免费 | 1330篇 |
专业分类
电工技术 | 1471篇 |
综合类 | 1174篇 |
化学工业 | 199篇 |
金属工艺 | 159篇 |
机械仪表 | 709篇 |
建筑科学 | 188篇 |
矿业工程 | 89篇 |
能源动力 | 163篇 |
轻工业 | 72篇 |
水利工程 | 99篇 |
石油天然气 | 45篇 |
武器工业 | 129篇 |
无线电 | 1710篇 |
一般工业技术 | 505篇 |
冶金工业 | 286篇 |
原子能技术 | 146篇 |
自动化技术 | 5223篇 |
出版年
2024年 | 21篇 |
2023年 | 136篇 |
2022年 | 162篇 |
2021年 | 222篇 |
2020年 | 280篇 |
2019年 | 298篇 |
2018年 | 270篇 |
2017年 | 391篇 |
2016年 | 465篇 |
2015年 | 447篇 |
2014年 | 615篇 |
2013年 | 816篇 |
2012年 | 705篇 |
2011年 | 781篇 |
2010年 | 603篇 |
2009年 | 669篇 |
2008年 | 687篇 |
2007年 | 723篇 |
2006年 | 581篇 |
2005年 | 556篇 |
2004年 | 453篇 |
2003年 | 370篇 |
2002年 | 292篇 |
2001年 | 268篇 |
2000年 | 251篇 |
1999年 | 190篇 |
1998年 | 165篇 |
1997年 | 154篇 |
1996年 | 108篇 |
1995年 | 101篇 |
1994年 | 100篇 |
1993年 | 98篇 |
1992年 | 74篇 |
1991年 | 69篇 |
1990年 | 56篇 |
1989年 | 33篇 |
1988年 | 17篇 |
1987年 | 18篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 17篇 |
1983年 | 21篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1965年 | 3篇 |
1964年 | 5篇 |
1962年 | 3篇 |
1958年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
21.
22.
D. Roy 《International journal for numerical methods in engineering》2004,61(5):764-790
Sample pathwise numerical integration of noise-driven engineering dynamical systems cannot generally be performed beyond a limited level of accuracy, especially when the noise processes are modelled using (filtered) white noises. Recently, a locally transversal linearization (LTL) strategy has been proposed by the author (Proc Roy Soc London A 2001; 457 :539–566) for direct integration of deterministic and stochastic non-linear dynamical systems. The present effort is focussed on a host of extensions along with detailed theoretical error analyses of the linearization approach, especially as applied to problems in non-linear stochastic engineering dynamics. Thus, to begin with, estimates of local and global error orders in the basic LTL scheme are obtained separately for the displacement and velocity vectors when the system is driven either by a set of additive noises or by an arbitrary combination of (independently evolving) additive and multiplicative noises. Following this, a new family of higher-order LTL schemes is proposed in order to improve upon the basic LTL method and the associated error orders are established. A stepwise implementation of the lower- and higher-order versions of the LTL method, along with certain computational aspects, is also outlined. The proposed schemes are numerically illustrated, to a limited extent, for a single degree-of-freedom (SDOF) and a two degree-of-freedom (TDOF) non-linear engineering systems under additive and/or multiplicative white noise excitations. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
23.
24.
Gert van der Horn Johan H. Huijsing 《Analog Integrated Circuits and Signal Processing》1997,14(3):207-222
In many applications electronic sensors are used toimprove performance and reliability of measurement systems. Suchsensors should provide a correct transfer from the physical signalto be measured to the electrical output signal. One importantstep to achieve this, is to calibrate each sensor by applyingdifferent reference input signals and adjusting the sensor transferaccordingly. Besides expensive reference equipment the calibrationprocess takes much time and attention per individual sensor,which means a considerable increase in sensor production costs.By including at the sensor or sensor interface chip a programmablecalibration facility the calibration of such smart sensors caneasily be automated and can be executed for a batch of sensorsat a time, thus minimizing the calibration time and costs. Thispaper presents a calibration method and options for integrationin the smart sensor concept, in hardware as well as in software.An advantage of the proposed method is that it does not needa large matrix of calibration data, which needs to be storedin a look-up table or converted into a correction formula, butinstead it uses a step-by-step approach to correct the sensortransfer at each calibration measurement until the error is sufficientlysmall. 相似文献
25.
Andrzej Banaszuk Andrzej Święch John Hauser 《Mathematics of Control, Signals, and Systems (MCSS)》1996,9(3):207-241
We study the problem of approximating one-dimensional nonintegrable codistributions by integrable ones and apply the resulting
approximations to approximate feedback linearization of single-input systems. The approach derived in this paper allows a
linearizable nonlinear system to be found that is close to the given system in a least-squares (L
2) sense. A linearly controllable single-input affine nonlinear system is feedback linearizable if and only if its characteristic
distribution is involutive (hence integrable) or, equivalently, any characteristic one-form (a one-form that annihilates the
characteristic distribution) is integrable. We study the problem of finding (least-squares approximate) integrating factors
that make a fixed characteristic one-form close to being exact in anL
2 sense. A given one-form can be decomposed into exact and inexact parts using the Hodge decomposition. We derive an upper
bound on the size of the inexact part of a scaled characteristic one-form and show that a least-squares integrating factor
provides the minimum value for this upper bound. We also consider higher-order approximate integrating factors that scale
a nonintegrable one-form in a way that the scaled form is closer to being integrable inL
2 together with some derivatives and derive similar bounds for the inexact part. This allows a linearizable nonlinear system
that is close to the given system in a least-squares (L
2) sense together with some derivatives to be found. The Sobolev embedding techniques allow us to obtain an upper bound on
the uniform (L
∞) distance between the nonlinear system and its linearizable approximation.
This research was supported in part by NSF under Grant PYI ECS-9396296, by AFOSR under Grant AFOSR F49620-94-1-0183, and by
a grant from the Hughes Aircraft Company. 相似文献
26.
本文提出励磁电流可自动控制的他励式双高调速系统设计方案。系统在提升特别是在下放重物时,具有较硬的机械性;在负载10-100%的变化范围内,可实现最大偏差Δnmax/nmin100%≤10%,调速范围D≥10;在满载运行条件下,可节约电能80%以上。 相似文献
27.
28.
29.
不确定控制系统的输出反馈镇定 总被引:4,自引:0,他引:4
本文研究具有匹配和非匹配不确定性系统的输出反馈镇定。在对不确定性的增长性作适当限制的条件下,利用本文引入输出反馈严格正实系统的概念,构造了保证团环系统在开球B上或在R^n上指数式稳定的光滑或解析输出反馈控制律。 相似文献
30.