全文获取类型
收费全文 | 33812篇 |
免费 | 3888篇 |
国内免费 | 3201篇 |
专业分类
电工技术 | 3321篇 |
综合类 | 4931篇 |
化学工业 | 1474篇 |
金属工艺 | 624篇 |
机械仪表 | 2246篇 |
建筑科学 | 2218篇 |
矿业工程 | 467篇 |
能源动力 | 804篇 |
轻工业 | 309篇 |
水利工程 | 800篇 |
石油天然气 | 460篇 |
武器工业 | 347篇 |
无线电 | 3584篇 |
一般工业技术 | 3867篇 |
冶金工业 | 371篇 |
原子能技术 | 149篇 |
自动化技术 | 14929篇 |
出版年
2024年 | 151篇 |
2023年 | 400篇 |
2022年 | 562篇 |
2021年 | 660篇 |
2020年 | 976篇 |
2019年 | 993篇 |
2018年 | 908篇 |
2017年 | 1208篇 |
2016年 | 1326篇 |
2015年 | 1312篇 |
2014年 | 1801篇 |
2013年 | 2669篇 |
2012年 | 2269篇 |
2011年 | 2288篇 |
2010年 | 1778篇 |
2009年 | 1988篇 |
2008年 | 2097篇 |
2007年 | 2368篇 |
2006年 | 2027篇 |
2005年 | 1806篇 |
2004年 | 1498篇 |
2003年 | 1318篇 |
2002年 | 1139篇 |
2001年 | 1067篇 |
2000年 | 993篇 |
1999年 | 794篇 |
1998年 | 647篇 |
1997年 | 667篇 |
1996年 | 532篇 |
1995年 | 454篇 |
1994年 | 416篇 |
1993年 | 310篇 |
1992年 | 289篇 |
1991年 | 227篇 |
1990年 | 178篇 |
1989年 | 140篇 |
1988年 | 117篇 |
1987年 | 62篇 |
1986年 | 64篇 |
1985年 | 43篇 |
1984年 | 68篇 |
1983年 | 37篇 |
1982年 | 48篇 |
1981年 | 32篇 |
1980年 | 39篇 |
1979年 | 39篇 |
1978年 | 20篇 |
1977年 | 30篇 |
1976年 | 15篇 |
1975年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
We obtain a necessary and sufficient condition for a discrete-time nonlinear system to be locally state equivalent to the nonlinear observer form. The result looks similar to the continuous counterpart except for the fact that Ad-operation is utilized instead of ad-operation. 相似文献
66.
Ali J. Koshkouei 《International Journal of Adaptive Control and Signal Processing》2008,22(9):859-874
Passivity with sliding mode control for a class of nonlinear systems with and without unknown parameters is considered in this paper. In fact, a method for deriving a nonlinear system with external disturbances to a passive system is considered. Then a passive sliding mode control is designed corresponding to a given storage function. The passivity property guarantees the system stability while sliding mode control techniques assures the robustness of the proposed controller. When the system includes unknown parameters, an appropriate updated law is obtained so that the new transformed system is passive. The passivation property of linear systems with sliding mode is also analysed. The linear and nonlinear theories are applied to a simple pendulum model and the gravity‐flow/pipeline system, respectively. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
67.
介绍了补偿中子测井仪刻度的基本原理及在Windows98平台下利用Borland C Builder5.0^[1]编程环境开发的中子测井仪刻度管理软件,实现了对中子测井仪的刻度管理,列举了应用实例。 相似文献
68.
In this paper, we present a control methodology for a class of discrete time nonlinear systems that depend on a possibly exogenous scheduling variable. This class of systems consists of an interpolation of nonlinear dynamic equations in strict feedback form, and it may represent systems with a time-varying nonlinear structure. Moreover, this class of systems is able to represent some cases of gain scheduling control, Takagi-Sugeno fuzzy systems, as well as input-output realizations of nonlinear systems which are approximated via localized linearizations. We present two control theorems, one using what we call a “global” approach (akin to traditional backstepping), and a “local” approach, our main result, where backstepping is again used but the control law is an interpolation of local control terms. An aircraft wing rock regulation problem with varying angle of attack is used to illustrate and compare the two approaches. 相似文献
69.
A novel MINLP-based representation of the original complex model for predicting gasoline emissions 总被引:1,自引:1,他引:0
The Environmental Protection Agency (EPA) introduced Reformulated Gasoline (RFG) requirements as a measure to reduce emissions from gasoline-powered vehicles in certain geographic areas. As part of this effort, the EPA developed empirical models for predicting emissions as a function of gasoline properties and established statutory baseline emissions from a representative set of gasolines. All reformulated gasoline requires certification via this model, known as the Complex Model, and all refiners and importers calculate emissions performance reductions from the statutory baseline gasoline. The current representation of the Complex Model is extremely difficult to implement within refinery operations models or to use in combination with models for designer gasoline. RFG and boutique fuels are key driving forces in the North American refining industry.The RFG models introduce increasingly complex constraints with the major limitation that they are implicitly defined through a series of complicated disjunctions assembled by the EPA in the form of spreadsheets. This implicit and cumbersome representation of the emissions predictive models renders rigorous optimization and sensitivity analysis very difficult to address directly. In this paper, we discuss how the federal government requirements for reformulated gasoline can be restated as a set of mixed-integer nonlinear programming (MINLP) constraints with the aid of disjunctive programming techniques. We illustrate the use of this model with two simple example fuel blending problems. 相似文献
70.
Miguel Palomino Narciso Martí-Oliet Alberto Verdejo 《Electronic Notes in Theoretical Computer Science》2005,124(1):3
This paper is an introduction to rule-based programming in Maude. We illustrate in particular the use of operator attributes to structure the state of a system, and the difference between equations and rules. We use well-known mathematical games and puzzles for our examples illustrating the expressive power of Maude. 相似文献