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   74463篇
  免费   12947篇
  国内免费   6860篇
电工技术   14308篇
技术理论   3篇
综合类   6615篇
化学工业   2448篇
金属工艺   1437篇
机械仪表   6715篇
建筑科学   2612篇
矿业工程   2790篇
能源动力   1261篇
轻工业   4487篇
水利工程   1001篇
石油天然气   3381篇
武器工业   1181篇
无线电   12873篇
一般工业技术   4468篇
冶金工业   1306篇
原子能技术   594篇
自动化技术   26790篇
  2024年   793篇
  2023年   1972篇
  2022年   3298篇
  2021年   3664篇
  2020年   3717篇
  2019年   2775篇
  2018年   2438篇
  2017年   3089篇
  2016年   3319篇
  2015年   3793篇
  2014年   5804篇
  2013年   4834篇
  2012年   6295篇
  2011年   6446篇
  2010年   4828篇
  2009年   4867篇
  2008年   4847篇
  2007年   5390篇
  2006年   4452篇
  2005年   3692篇
  2004年   2900篇
  2003年   2449篇
  2002年   1812篇
  2001年   1440篇
  2000年   1168篇
  1999年   916篇
  1998年   670篇
  1997年   503篇
  1996年   468篇
  1995年   366篇
  1994年   234篇
  1993年   194篇
  1992年   181篇
  1991年   145篇
  1990年   118篇
  1989年   62篇
  1988年   63篇
  1987年   34篇
  1986年   34篇
  1985年   28篇
  1984年   27篇
  1983年   24篇
  1982年   19篇
  1981年   22篇
  1980年   23篇
  1979年   10篇
  1978年   6篇
  1976年   6篇
  1975年   7篇
  1951年   5篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
可靠的网格作业调度机制   总被引:1,自引:1,他引:0  
陶永才  石磊 《计算机应用》2010,30(8):2066-2069
针对网格环境的动态性特征,提出了一种可靠的网格作业调度机制(DGJS)。按照作业完成时间期限,DGJS将作业分为:高QoS级、低QoS级和无QoS级,不同QoS级作业有不同的调度优先权;基于资源可用性预测,DGJS采用基于可靠性代价的作业调度策略,将作业尽可能调度到可靠性高的资源节点;另外,DGJS对不同QoS级作业采用不同的容错策略,在保证故障容错的同时,节省网格资源。实验表明:在动态的网格环境下,较之传统的网格作业调度算法,DGJS提高了作业成功率,减少了作业完成时间。  相似文献   
982.
In this paper we present new edge detection algorithms which are motivated by recent developments on edge-adapted reconstruction techniques [F. Aràndiga, A. Cohen, R. Donat, N. Dyn, B. Matei, Approximation of piecewise smooth functions and images by edge-adapted (ENO-EA) nonlinear multiresolution techniques, Appl. Comput. Harmon. Anal. 24 (2) (2008) 225–250]. They are based on comparing local quantities rather than on filtering and thresholding. This comparison process is invariant under certain transformations that model light changes in the image, hence we obtain edge detection algorithms which are insensitive to changes in illumination.  相似文献   
983.
Text detection is important in the retrieval of texts from digital pictures, video databases and webpages. However, it can be very challenging since the text is often embedded in a complex background. In this paper, we propose a classification-based algorithm for text detection using a sparse representation with discriminative dictionaries. First, the edges are detected by the wavelet transform and scanned into patches by a sliding window. Then, candidate text areas are obtained by applying a simple classification procedure using two learned discriminative dictionaries. Finally, the adaptive run-length smoothing algorithm and projection profile analysis are used to further refine the candidate text areas. The proposed method is evaluated on the Microsoft common test set, the ICDAR 2003 text locating set, and an image set collected from the web. Extensive experiments show that the proposed method can effectively detect texts of various sizes, fonts and colors from images and videos.  相似文献   
984.
This study aims to develop an intelligent algorithm by integrating the independent component analysis (ICA) and support vector machine (SVM) for monitoring multivariate processes. For developing a successful SVM-based fault detector, the first step is feature extraction. In real industrial processes, process variables are rarely Gaussian distributed. Thus, this study proposes the application of ICA to extract the hidden information of a non-Gaussian process before conducting SVM. The proposed fault detector will be implemented via two simulated processes and a case study of the Tennessee Eastman process. Results demonstrate that the proposed method possesses superior fault detection when compared to conventional monitoring methods, including PCA, ICA, modified ICA, ICA–PCA and PCA–SVM.  相似文献   
985.
With the advancement of MEMS technologies, sensor networks have opened up broad application prospects. An important issue in wireless sensor networks is object detection and tracking, which typically involves two basic components, collaborative data processing and object location reporting. The former aims to have sensors collaborating in determining a concise digest of object location information, while the latter aims to transport a concise digest to sink in a timely manner. This issue has been intensively studied in individual objects, such as intruders. However, the characteristic of continuous objects has posed new challenges to this issue. Continuous objects can diffuse, increase in size, or split into multiple continuous objects, such as a noxious gas. In this paper, a scalable, topology-control-based approach for continuous object detection and tracking is proposed. Extensive simulations are conducted, which show a significant improvement over existing solutions.  相似文献   
986.
This paper considers observer-based actuator fault detection and reconstruction problems for uncertain nonlinear systems. Based on a kind of full-order observer which is robust to disturbances but sensitive to actuator faults, a single detection observer is constructed to produce a residual which can be used to alarm the occurrence of the actuator faults when at least one actuator fault occurs indeed. The full-order observer is adaptive one because an adaptation law which can adjust the Lipschitz constant of Lipschitz term is introduced. For this reason, the Lipschitz constant can be unknown in our design. After this, a kind of reduced-order observer is developed by choosing a special observer gain matrix. Based on the reduced-order observer, we provide a kind of unknown information estimating method which can be used to not only reconstruct the actuator faults but also estimate the disturbances of the system. In simulation, a real model of the seventh-order aircraft is used to illustrate the effectiveness of the proposed methods.  相似文献   
987.
多带联合检测在OFDM频谱感知中的应用   总被引:3,自引:3,他引:0       下载免费PDF全文
针对传统频谱感知方法局限在单个频带上的问题,介绍一种多带联合检测的频谱感知方法。以正交频分复用系统为背景,基于能量检测方法,联合多个频带选取最优门限向量,使其在总干扰受限的情况下,总吞吐量达到最大。仿真结果表明,与传统使用一致门限值的多带检测方法相比,该方法的有效性得到提高。  相似文献   
988.
为提高软测量的模型精度,剔除建模数据中的过失误差,提出采用Bagging-PCA方法进行误差侦破。利用Bagging算法的集成思想,改善单变量大误差对经典PCA的影响,提高算法稳定性,实现数据的过失误差侦破。用该方法对丙烯浓度的软测量进行过失误差侦破,取得了良好的效果。  相似文献   
989.
miRNA检测技术进展   总被引:2,自引:0,他引:2  
miRNA做为一种非常重要的非编码蛋白的RNA.广泛存在于植物、病毒、哺乳动物当中.因其在细胞增殖、细胞死亡、肿瘤发生和哺乳动物细胞生长中重要的调节功能,其检测技术也受到越来越多的关注,很多关键的检测技术,比如印迹技术,阵列杂交技术,反转录PCR技术等等都在miRNA的检测中发挥了巨大的实用价值.该文基于此对miRNA近几年的检测技术进行了具体的综述.  相似文献   
990.
该文在描述决策树分类算法的基础上,叙述了决策树分类算法用于网络入侵检测领域,给出了决策树分类模型的构造过程,并说明了应用基于决策树模型检测入侵的过程。最后用KDD CUP 99数据进行实验,验证了用本文描述的方法检测入侵行为的有效性。  相似文献   
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