全文获取类型
收费全文 | 41234篇 |
免费 | 3481篇 |
国内免费 | 3398篇 |
专业分类
电工技术 | 3654篇 |
技术理论 | 6篇 |
综合类 | 3058篇 |
化学工业 | 2528篇 |
金属工艺 | 489篇 |
机械仪表 | 1731篇 |
建筑科学 | 1493篇 |
矿业工程 | 365篇 |
能源动力 | 1430篇 |
轻工业 | 518篇 |
水利工程 | 365篇 |
石油天然气 | 340篇 |
武器工业 | 234篇 |
无线电 | 2791篇 |
一般工业技术 | 3092篇 |
冶金工业 | 1135篇 |
原子能技术 | 167篇 |
自动化技术 | 24717篇 |
出版年
2024年 | 41篇 |
2023年 | 605篇 |
2022年 | 422篇 |
2021年 | 756篇 |
2020年 | 1043篇 |
2019年 | 1106篇 |
2018年 | 1026篇 |
2017年 | 1387篇 |
2016年 | 1515篇 |
2015年 | 1378篇 |
2014年 | 2354篇 |
2013年 | 3557篇 |
2012年 | 1955篇 |
2011年 | 2447篇 |
2010年 | 1823篇 |
2009年 | 2313篇 |
2008年 | 2362篇 |
2007年 | 2457篇 |
2006年 | 2160篇 |
2005年 | 1970篇 |
2004年 | 1671篇 |
2003年 | 1560篇 |
2002年 | 1465篇 |
2001年 | 1202篇 |
2000年 | 1173篇 |
1999年 | 1058篇 |
1998年 | 923篇 |
1997年 | 824篇 |
1996年 | 708篇 |
1995年 | 660篇 |
1994年 | 591篇 |
1993年 | 544篇 |
1992年 | 423篇 |
1991年 | 393篇 |
1990年 | 311篇 |
1989年 | 237篇 |
1988年 | 208篇 |
1987年 | 174篇 |
1986年 | 140篇 |
1985年 | 181篇 |
1984年 | 188篇 |
1983年 | 168篇 |
1982年 | 147篇 |
1981年 | 96篇 |
1980年 | 72篇 |
1979年 | 86篇 |
1978年 | 62篇 |
1977年 | 67篇 |
1976年 | 19篇 |
1975年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Bert Van Keulen 《国际强度与非线性控制杂志
》1994,4(4):521-552
》1994,4(4):521-552
In this paper we extend the finite-dimensional results for the H∞-control problem with measurement-feedback to a large class of infinite-dimensional systems, allowing for a certain type of unboundedness in the input and output operators (the Pritchard-Salamon class). The main result of the paper relates the solvability to the suboptimal H∞-control problem to the existence of stabilizing solutions to certain operator Riccati equations. Furthermore, a characterization of all suboptimal controllers is given. 相似文献
62.
Wen-Hua Chen 《国际强度与非线性控制杂志
》1994,4(5):713-722
》1994,4(5):713-722
The problem of design of minimax robust LQG controllers for linear systems with parameter and noise uncertainties is considered in this paper. Necessary and sufficient conditions for converting this problem to a two-person, zero-sum continuous game problem are presented. A simple procedure for design of a suboptimal minimax robust LQG controller, i.e., the LQG controller for least-favourable model, is proposed. Necessary and sufficient conditions for the existence of a saddle point are established. Under these conditions, the controller obtained is exactly the minimax LQG controller. When there does not exist a saddle point, the worst-case error between the controller obtained and the minimax robust LQG controllers under described uncertainties is bounded. 相似文献
63.
Matthew R. James 《国际强度与非线性控制杂志
》1994,4(6):791-806
》1994,4(6):791-806
In this paper we present a numerical method for estimating the current state of a nonlinear control system. We use finite differences to discretize a modified version of the finite-time observer equations in James. The discretized equations are simple and easily programmed. The convergence and accuracy of the scheme is proved, and the scheme enjoys a number of important properties: availability of rate of convergence estimates, good robustness characteristics, and the ability to handle certain types of discontinuities in the observations. The major disadvantage is that the number of grid points required increases exponentially with the number of state dimensions. 相似文献
64.
65.
Management of multidimensional discrete data 总被引:1,自引:0,他引:1
Peter Baumann Ph.D. 《The VLDB Journal The International Journal on Very Large Data Bases》1994,3(4):401-444
Spatial database management involves two main categories of data: vector and raster data. The former has received a lot of in-depth investigation; the latter still lacks a sound framework. Current DBMSs either regard raster data as pure byte sequences where the DBMS has no knowledge about the underlying semantics, or they do not complement array structures with storage mechanisms suitable for huge arrays, or they are designed as specialized systems with sophisticated imaging functionality, but no general database capabilities (e.g., a query language). Many types of array data will require database support in the future, notably 2-D images, audio data and general signal-time series (1-D), animations (3-D), static or time-variant voxel fields (3-D and 4-D), and the ISO/IEC PIKS (Programmer's Imaging Kernel System) BasicImage type (5-D). In this article, we propose a comprehensive support ofmultidimensional discrete data (MDD) in databases, including operations on arrays of arbitrary size over arbitrary data types. A set of requirements is developed, a small set of language constructs is proposed (based on a formal algebraic semantics), and a novel MDD architecture is outlined to provide the basis for efficient MDD query evaluation. 相似文献
66.
可分2-D系统是一类具有良好特性的重要的特殊2-D系统,它在多方面均有重要的应用.本文在已有结果的基础上对具有可分性的2-D多输入多输出系统在再实现问题、渐近稳定性代数判据、状态观测器设计等方面进行了较为广泛的研究,得到了许多较好的结果. 相似文献
67.
Stochastic extensions to Petri nets have gained widespread acceptance as a method for describing the dynamic behavior of discrete-event
systems. Both simulation and analytic methods have been proposed to solve such models. This paper describes a set of efficient
procedures for simulating models that are represented as stochastic activity networks (SANs, a variant of stochastic Petri
nets) and composed SAN-based reward models (SBRMs). Composed SBRMs are a hierarchical representation for SANs, in which individual
SAN models can be replicated and joined together with other models, in an iterative fashion. The procedures exploit the hierarchical
structure and symmetries introduced by the replicate operation in a composed SBRM to reduce the cost of future event list
management. The procedures have been implemented as part of a larger performance-dependability modeling package known asUltraSAN, and have been applied to real, large-scale applications.
This work was supported in part by the Digital Equipment Corporation Faculty Program: Incentives for Excellence. 相似文献
68.
We consider a class of linear infinite-dimensional systems subject to boundary uncertainties, which are linear and time-invariant. Using a deterministic approach to the design of stabilizing feedback controls, uniform exponential stability of the zero state is achieved. Lyapunov techniques are combined with Datko or Ichikawa theory. Three illustrative examples are presented. 相似文献
69.
William Winder 《Computers and the Humanities》2002,36(3):295-306
Parallel to, and to some degree inreaction to French poststructuralisttheorization (as championed by Derrida,Foucault, and Lacan, among others) is a Frenchneo-structuralism built directly on theachievements of structuralism using electronicmeans. This paper examines some exemplaryapproaches to text analysis in thisneo-structuralist vein: SATOR's topoidictionary, the WinBrill POS tagger andFrançois Rastier's interpretativesemantics. I consider how a computer-assisted``Wissenschaft' accumulation of expertisecomplements the neo-structuralist approach.Ultimately, electronic critical studies will bedefined by their strategic position at theintersection of the two chief technologiesshaping our society: the new informationprocessing technology of computers and therepresentational techniques that haveaccumulated for centuries in texts.Understanding how these two informationmanagement paradigms complement each other is akey issue for the humanities, for computerscience, and vital to industry, even beyond thenarrow realm of the language industries. Thedirection of critical studies, a small planetlong orbiting in only rarefied academiccircles, will be radically altered by the sheersize of the economic stakes implied by a newkind of text, the industrial text, thetechnological heart of an information society. 相似文献
70.
Design and Implementation of a Flexible Manufacturing Control System Using Neural Network 总被引:1,自引:0,他引:1
Magdy M. Abdelhameed Farid A. Tolbah 《International Journal of Flexible Manufacturing Systems》2002,14(3):263-279
Design and implementation of a sequential controller based on the concept of artificial neural networks for a flexible manufacturing system are presented. The recurrent neural network (RNN) type is used for such a purpose. Contrary to the programmable controller, an RNN-based sequential controller is based on a definite mathematical model rather than depending on experience and trial and error techniques. The proposed controller is also more flexible because it is not limited by the restrictions of the finite state automata theory. Adequate guidelines of how to construct an RNN-based sequential controller are presented. These guidelines are applied to different case studies. The proposed controller is tested by simulations and real-time experiments. These tests prove the successfulness of the proposed controller performances. Theoretical as well as experimental results are presented and discussed indicating that the proposed design procedure using Elman's RNN can be effective in designing a sequential controller for event-based type manufacturing systems. In addition, the simulation results assure the effectiveness of the proposed controller to outperform the effect of noisy inputs. 相似文献