全文获取类型
收费全文 | 36019篇 |
免费 | 3006篇 |
国内免费 | 1467篇 |
学科分类
工业技术 | 40492篇 |
出版年
2024年 | 133篇 |
2023年 | 669篇 |
2022年 | 960篇 |
2021年 | 1460篇 |
2020年 | 1098篇 |
2019年 | 955篇 |
2018年 | 1046篇 |
2017年 | 1148篇 |
2016年 | 1014篇 |
2015年 | 1353篇 |
2014年 | 1793篇 |
2013年 | 2120篇 |
2012年 | 2277篇 |
2011年 | 2361篇 |
2010年 | 2058篇 |
2009年 | 2043篇 |
2008年 | 1840篇 |
2007年 | 1834篇 |
2006年 | 1978篇 |
2005年 | 1728篇 |
2004年 | 1129篇 |
2003年 | 1030篇 |
2002年 | 970篇 |
2001年 | 852篇 |
2000年 | 970篇 |
1999年 | 1019篇 |
1998年 | 847篇 |
1997年 | 719篇 |
1996年 | 713篇 |
1995年 | 568篇 |
1994年 | 466篇 |
1993年 | 331篇 |
1992年 | 259篇 |
1991年 | 205篇 |
1990年 | 150篇 |
1989年 | 115篇 |
1988年 | 94篇 |
1987年 | 49篇 |
1986年 | 36篇 |
1985年 | 24篇 |
1984年 | 17篇 |
1983年 | 12篇 |
1982年 | 22篇 |
1981年 | 13篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1959年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
in order to obtain the information and achieve the effective control of crop straw fire spatial distribution in Central China Region.The MODIS L1B remote sensing datasets during 2014 for the main data source in this article,and combined with land use data,the farmland of Central China Region was taken as study region.Based on the enhanced contextual fire remote sensing detection algorithm,and make full use of the theoretical knowledge of quantitative remote sensing and Geospatial Data Abstraction Library (GDAL)and other technical means,to achieve the crop straw fire recognition in Central China Region.Using Ministry of Environmental Protection of the People’s Republic of China release the daily newspaper of crop straw fire in China and the standard fire products (MYD14)of MODIS for the comparative analysis of the quantitative and spatial.The results indicate that the algorithmof this paper can achieve crop straw fire remote sensing monitoring of this study region effectively,and the parameters can be adjusted in real time based on the characteristic of the study region,and improve the automation and working efficiency of crop straw fire monitoring. 相似文献
993.
We consider a distributed consensus problem for continuous‐time multi‐agent systems with set constraints on the final states. To save communication costs, an event‐triggered communication‐based protocol is proposed. By comparing its own instantaneous state with the one previously broadcasted to neighbours, each agent determines the next communication time. Based on this event‐triggered communication, each agent is not required to continuously monitor its neighbours' state and the communication only happens at discrete time instants. We show that, under some mild conditions, the constrained consensus of the multi‐agent system with the proposed protocol can be achieved with an exponential convergence rate. A lower bound of the transmission time intervals is provided that can be adjusted by choosing different values of parameters. Numerical examples illustrate the results. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
994.
Heterogeneous consensus of higher‐order multi‐agent systems with mismatched uncertainties using sliding mode control
下载免费PDF全文
![点击此处可从《国际强度与非线性控制杂志<br>》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A robust consensus controller is proposed for heterogeneous higher‐order nonlinear multi‐agent systems, when the agent dynamics are involved with mismatched uncertainties. A distributed consensus protocol based on a time‐varying nonhomogeneous finite‐time disturbance observer and sliding mode control is designed to realize the network consensus of higher‐order multi‐agent systems. The time‐varying finite‐time disturbance observer overcomes the problem of peaking value near the initial time caused by the constant gain one and is designed to estimate the uncertainties and to mitigate the effect of mismatched uncertainties during the sliding mode. To eliminate the chattering phenomenon and ensure finite‐time convergence to the sliding surface, the control law is designed by using the super twisting algorithm. Finally numerical simulations are given to illustrate the validity of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
995.
Semi‐global output feedback control for nonlinear systems with uncertain time‐delay and output function
下载免费PDF全文
![点击此处可从《国际强度与非线性控制杂志<br>》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This paper considers semi‐global output feedback control for more general nonlinear systems with unknown time‐delay and output function whose derivative is unbounded from above. By introducing a new observer and using the backstepping design method and the Razumikhin stability theorem, an output feedback controller is constructed to achieve a semi‐global stability. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
996.
地面供配电系统一直存在体积过于庞大、系统通用性稳定性差问题;基于通用模块化的设计方案,从基本功能实现模块的角度,将系统划分为功率继电器模块、信号继电器模块、PXI控制模块、地面电缆模块、软件实现模块等,通过对这些模块的通用性设计及部分软硬件功能的整合,实现了减少系统体积规模、加大系统集成化及小型化程度、提高系统间通用性及鲁棒性的目的。 相似文献
997.
根据应急响应的需求,为了快速、自动且稳定地获取遥感区域的全覆盖图像,提出一种直接适用于无人机序列图像的拼接方法.利用无人机平台上的低精度飞行控制系统与无标定的非量测相机获取序列图像,并进行快速自动配准;根据全局地面点在多视图像上的投影点集,基于单应矩阵和自由投影中心建立整体优化误差方程,并利用Levenberg-Marquardt非线性迭代求解;再根据并行几何定位拼接线的快速处理方法进行图像插值和融合,实现全流程自动化的图像输出.通过灾害应急响应的无人机遥感实验结果表明,在1h内处理完成450幅序列图像,获得定位精度小于3个像素的0.05m分辨率图像;文中方法适合无人机的序列图像配准,为应急响应提供了有效的技术支持. 相似文献
998.
999.
1000.
Attainability of the minimum data rate for stabilization of linear systems via logarithmic quantization 总被引:1,自引:0,他引:1
This paper investigates the attainability of the minimum average data rate for stabilization of linear systems via logarithmic quantization. It is shown that a finite-level logarithmic quantizer suffices to approach the well-known minimum average data rate for stabilizing an unstable linear discrete-time system under two basic network configurations. In particular, we derive explicit finite-level logarithmic quantizers and the corresponding controllers to approach the minimum average data rate. 相似文献