全文获取类型
收费全文 | 6109篇 |
免费 | 175篇 |
国内免费 | 231篇 |
专业分类
系统科学 | 429篇 |
丛书文集 | 82篇 |
教育与普及 | 42篇 |
理论与方法论 | 48篇 |
现状及发展 | 14篇 |
研究方法 | 2篇 |
综合类 | 5898篇 |
出版年
2025年 | 12篇 |
2024年 | 28篇 |
2023年 | 33篇 |
2022年 | 43篇 |
2021年 | 61篇 |
2020年 | 50篇 |
2019年 | 41篇 |
2018年 | 43篇 |
2017年 | 52篇 |
2016年 | 39篇 |
2015年 | 63篇 |
2014年 | 187篇 |
2013年 | 244篇 |
2012年 | 493篇 |
2011年 | 497篇 |
2010年 | 221篇 |
2009年 | 253篇 |
2008年 | 172篇 |
2007年 | 506篇 |
2006年 | 309篇 |
2005年 | 416篇 |
2004年 | 560篇 |
2003年 | 383篇 |
2002年 | 422篇 |
2001年 | 248篇 |
2000年 | 76篇 |
1999年 | 57篇 |
1998年 | 255篇 |
1997年 | 331篇 |
1996年 | 117篇 |
1995年 | 20篇 |
1994年 | 255篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1980年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有6515条查询结果,搜索用时 0 毫秒
1.
Stable local feature detection is a fundamental component of many stereo vision problems such as 3-D reconstruction, object localization, and object tracking. A robust method for extracting scale-invariant feature points is presented. First, the Harris corners in three-level pyramid are extracted. Then, the points detected at the highest level of the pyramid are correctly propagated to the lower level by pyramid based scale invariant (PBSI) method. The corners detected repeatedly in different levels are chosen as final feature points. Finally, the characteristic scale is obtained based on maximum entropy method. The experimental results show that the algorithm has low computation cost, strong antinoise capability, and excellent performance in the presence of significant scale changes. 相似文献
2.
The fault detection problem for the nonlinear networked control system (NCS) with packet dropout and delay is investigated.A nonlinear stochastic system model is proposed to account for the NCS with random packet dropout and networkinduced non-uniformly distributed time-varying delay in both from sensor to controller (S/C) and from controller to actuator (C/A).Based on the obtained NCS model,employing an observer-based fault detection filter as the residual generator,the addressed fault detection problem is converted into an auxiliary nonlinear H∞ control problem.Then,with the help of Lyapunov functional approach,a sufficient condition for the desired fault detection filter is constructed in terms of certain linear matrix inequalities,which depend on not only the delay interval but also the delay interval occurrence rate and successful packet communication rate.Especially,a trade-off phenomenon between the maximum allowable delay bound and successful data packet transmission rate is found,which is typically resulted from the limited bandwidth of communication networks.The effectiveness of the proposed method is demonstrated by a simulation example. 相似文献
3.
多指手抓取操作的仿真 总被引:2,自引:0,他引:2
本文分析了多指手仿真的基本任务,提出适合多指手的仿真系统结构,构造了一个基于微机的多指手仿真系统;该系统提供了能够在微机上运行的、交互式、具备动画显示功能的图形仿真工具;设计了友好的人机交互界面;同时本文对多指手的力规划、运动规划和姿态选择等问题作了详细的讨论;最后对多指手装配进行了仿真 相似文献
4.
ZUOBao-he FENGShan 《系统科学与系统工程学报(英文版)》2002,11(2):190-196
It's very important to dynamically assign the tasks to corresponding actors in workflow management system, especially in complex applications. This improves the flexibility of workflow systems. In this paper, a role-based workflow model with fuzzy optimized intelligent assignment is proposed and applied in the investment management system. A groupware-based software model is also proposed. 相似文献
5.
利用"囚徒困境"模型分析了利他行为者在与利己行为者的个体生存博弈中的不利处境.对于扩展的群体的生存博弈模型,从理论上证明了只要利他行为的回报充分大,群体的利他行为就会存在.利用元胞自动机的仿真验证了这一现象.对个体和群体两种生存博弈的分析表明,互惠利他行为是群体机制的一种涌现现象. 相似文献
6.
The fault detection problem for the nonlinear networked control system(NCS) with packet dropout and delay is investigated.A nonlinear stochastic system model is proposed to account for the NCS with random packet dropout and networkinduced non-uniformly distributed time-varying delay in both from sensor to controller(S/C) and from controller to actuator(C/A).Based on the obtained NCS model,employing an observer-based fault detection filter as the residual generator,the addressed fault detection problem is converted into an auxiliary nonlinear H∞ control problem.Then,with the help of Lyapunov functional approach,a sufficient condition for the desired fault detection filter is constructed in terms of certain linear matrix inequalities,which depend on not only the delay interval but also the delay interval occurrence rate and successful packet communication rate.Especially,a trade-off phenomenon between the maximum allowable delay bound and successful data packet transmission rate is found,which is typically resulted from the limited bandwidth of communication networks.The effectiveness of the proposed method is demonstrated by a simulation example. 相似文献
7.
考虑需求分布未知时的报童模型,假设需求分布的类型已知,但分布函数中含未知参数.证明了直接使用参数的估计量代替参数真实值的实施方法将使报童的期望利润偏离理论上的最优水平,只能得到一个次优结果.给出了两种修正的实施方法:一是基于大样本理论,通过收集足够多的需求样本数据,不断修正未知参数的相合估计值;另是在小样本下,直接修正未知参数的估计量. 相似文献
8.
9.
Xiong Chengyi~ Tian Jinwen~ & Liu Jian~ . Coll. of Electronic Information Engineering South Center Univ . for Nationalities Wnhan P.R. China . Inst. of Pattern Recognition & Artificial Intelligence Key Lab. of Education Ministry for Image Processing Intelligent Control Huazhong Univ. of Science & Technology Wuhan P.R. China 《系统工程与电子技术(英文版)》2006,17(2):303-308
1 .INTRODUCTIONThe discrete wavelet transform(DWT) is widely usedin many applications such as signal analysis and pro-cessing,as well asi mage compression,and adoptedtobecome an ingredient in many i mage compressionstandards ,such as JPEG2000 etc . This is because theDWTcan decompose the signals into different subba-nds with both ti me and frequency information and fa-cilitate to arrive a high compression ratio. Lifting-based wavelet[1 ,2]is also called as the secondly genera-tion wave… 相似文献
10.
影响力预测是企业在线负面口碑处理的关键环节.论文通过综合考虑信息发布者特征和信息内容特征两个维度形成特征空间,采用影响力衰减函数描述负面口碑影响力的多变趋势,提出了一种基于回归树与衰减函数的IMM-RTDF模型来预测在线负面口碑的影响力.实验结果表明,考虑信息内容特征有助于提高预测精度,同时发现用不同的衰减函数能更好地描述异质负面口碑影响力的变化趋势,进而能提高模型性能.基于此方法的在线负面口碑处理策略为企业进行客户关系管理和资源配置提供了决策支持. 相似文献