首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   898篇
  免费   84篇
  国内免费   7篇
电工技术   41篇
化学工业   242篇
金属工艺   35篇
机械仪表   54篇
建筑科学   18篇
矿业工程   3篇
能源动力   54篇
轻工业   45篇
水利工程   20篇
石油天然气   6篇
无线电   89篇
一般工业技术   198篇
冶金工业   28篇
原子能技术   3篇
自动化技术   153篇
  2023年   13篇
  2022年   14篇
  2021年   35篇
  2020年   42篇
  2019年   54篇
  2018年   73篇
  2017年   55篇
  2016年   61篇
  2015年   39篇
  2014年   69篇
  2013年   104篇
  2012年   58篇
  2011年   96篇
  2010年   59篇
  2009年   42篇
  2008年   35篇
  2007年   26篇
  2006年   23篇
  2005年   18篇
  2004年   13篇
  2003年   8篇
  2002年   9篇
  2001年   5篇
  2000年   8篇
  1999年   4篇
  1998年   7篇
  1997年   3篇
  1996年   3篇
  1995年   3篇
  1993年   1篇
  1991年   1篇
  1989年   3篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
排序方式: 共有989条查询结果,搜索用时 0 毫秒
1.
Association mining techniques search for groups of frequently co-occurring items in a market-basket type of data and turn these groups into business-oriented rules. Previous research has focused predominantly on how to obtain exhaustive lists of such associations. However, users often prefer a quick response to targeted queries. For instance, they may want to learn about the buying habits of customers that frequently purchase cereals and fruits. To expedite the processing of such queries, we propose an approach that converts the market-basket database into an itemset tree. Experiments indicate that the targeted queries are answered in a time that is roughly linear in the number of market baskets, N. Also, the construction of the itemset tree has O(N) space and time requirements. Some useful theoretical properties are proven.  相似文献   
2.
Real-time processing and compression of DNA microarray images.   总被引:1,自引:0,他引:1  
In this paper, we present a pipeline architecture specifically designed to process and compress DNA microarray images. Many of the pixilated image generation methods produce one row of the image at a time. This property is fully exploited by the proposed pipeline that takes in one row of the produced image at each clock pulse and performs the necessary image processing steps on it. This will remove the present need for sluggish software routines that are considered a major bottleneck in the microarray technology. Moreover, two different structures are proposed for compressing DNA microarray images. The proposed architecture is proved to be highly modular, scalable, and suited for a standard cell VLSI implementation.  相似文献   
3.
Robust control synthesis of linear time-invariant SISO polytopic systems is investigated using the polynomial approach. A convex set of all stabilizing controllers for a polytopic system is given over an infinite-dimensional space. A finite-dimensional approximation of this set is obtained using the orthonormal basis functions and represented by a set of LMIs thanks to the KYP lemma. Then, an LMI based convex optimization problem for robust pole placement with sensitivity function shaping in two- and infinity-norm is proposed. The simulation results show the effectiveness of the proposed method.  相似文献   
4.
5.
This paper investigates the state feedback stabilization problem for a class of positive switched systems with time-varying delays under asynchronous switching in the frameworks of continuous-time and discrete-time dynamics. The so-called asynchronous switching means that the switches between the candidate controllers and system modes are asynchronous. By constructing an appropriate co-positive type Lyapunov-Krasovskii functional and further allowing the functional to increase during the running time of active subsystems, sufficient conditions are provided to guarantee the exponential stability of the resulting closed-loop systems, and the corresponding controller gain matrices and admissible switching signals are presented. Finally, two illustrative examples are given to show the effectiveness of the proposed methods.  相似文献   
6.
A combination of crosslinked poly(4‐vinylpyridinium)chloride [P4‐H]Cl ( I ) and sodium nitrite or quaternized crosslinked poly(N‐methyl‐4‐vinylpyridinium)nitrite [P4‐Me]NO2 ( II ) was used as effective nitrosating agents for the N‐nitrosation of secondary amines under mild and heterogeneous conditions in moderate to excellent yields. The spent polymeric reagents can usually be removed quantitatively and regenerated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1064–1067, 2007  相似文献   
7.
In this paper, the problem of non‐fragile observer‐based H control for discrete‐time switched delay systems is investigated. Both data missing and time delays are taken into account in the links from sensors to observers and from controllers to actuators. Because data missing satisfies the Bernoulli distribution, such problem is transformed into an H control problem for stochastic switched delay systems. Average dwell time approach is used to obtain sufficient conditions on the solvability of such problems. A numerical example and a real example for water quality control are provided to illustrate the effectiveness and potential applications of the proposed techniques. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
8.
Multimedia Tools and Applications - Image retargeting is the task of making images capable of being displayed on screens with different sizes. This work should be done so that high-level visual...  相似文献   
9.
Hubs are special facilities designed to act as switching, transshipment and sorting points in various distribution systems. Since hub facilities concentrate and consolidate flows, disruptions at hubs could have large effects on the performance of a hub network. In this paper, we have formulated the multiple allocation p-hub median problem under intentional disruptions as a bi-level game model. In this model, the follower’s objective is to identify those hubs the loss of which would most diminish service efficiency. Moreover, the leader’s objective is to identify the set of hubs to locate in order to minimize expected transportation cost while taking normal and failure conditions into account. We have applied two algorithms based on simulated annealing to solve the defined problem. In addition, the algorithms have been calibrated using the Taguchi method. Computational experiments on different instances indicate that the proposed algorithms would be efficient in practice.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号