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   15527篇
  免费   1935篇
  国内免费   1478篇
电工技术   1192篇
综合类   1060篇
化学工业   362篇
金属工艺   347篇
机械仪表   1237篇
建筑科学   271篇
矿业工程   142篇
能源动力   185篇
轻工业   102篇
水利工程   94篇
石油天然气   340篇
武器工业   229篇
无线电   3592篇
一般工业技术   778篇
冶金工业   148篇
原子能技术   78篇
自动化技术   8783篇
  2024年   89篇
  2023年   238篇
  2022年   397篇
  2021年   502篇
  2020年   559篇
  2019年   521篇
  2018年   480篇
  2017年   651篇
  2016年   688篇
  2015年   763篇
  2014年   1053篇
  2013年   984篇
  2012年   1064篇
  2011年   1227篇
  2010年   927篇
  2009年   1012篇
  2008年   1057篇
  2007年   1093篇
  2006年   923篇
  2005年   721篇
  2004年   591篇
  2003年   566篇
  2002年   434篇
  2001年   349篇
  2000年   276篇
  1999年   229篇
  1998年   240篇
  1997年   194篇
  1996年   165篇
  1995年   119篇
  1994年   120篇
  1993年   135篇
  1992年   96篇
  1991年   51篇
  1990年   50篇
  1989年   54篇
  1988年   49篇
  1987年   28篇
  1986年   39篇
  1985年   26篇
  1984年   38篇
  1983年   26篇
  1982年   27篇
  1981年   25篇
  1980年   23篇
  1979年   18篇
  1978年   6篇
  1977年   10篇
  1975年   2篇
  1973年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
This paper shows how the theory of nonlinear adaptive observers can be effectively used in the design of internal models for nonlinear output regulation. The theory substantially enhances the existing results in the context of adaptive output regulation, by allowing for not necessarily stable zero dynamics of the controlled plant and by weakening the standard assumption of having the steady-state control input generated by a linear system.  相似文献   
82.
When designing an accurate automated guidance system for vehicles, a major problem is sliding and pseudo-sliding effects. This is especially the case in agricultural applications, where five-centimetre accuracy with respect to the desired trajectory is required, although the vehicles are moving on slippery ground. It has been established that RTK GPS was a very suitable sensor to achieve automated guidance with such high precision: several control laws have been designed for vehicles equipped with this sensor, and provide the expected guidance accuracy as long as the vehicles do not slide. In previous work, further control developments have been proposed to take sliding into account: guidance accuracy in slippery environments has been shown to be preserved, except transiently at the beginning/end of curves. In this paper, the design of this control law is first recalled and discussed. A Model Predictive Control method is then applied in order to preserve accuracy of guidance even during these curvature transitions. Finally, the overall control scheme is implemented, and improvements with respect to previous guidance laws are demonstrated through full-scale experiments.  相似文献   
83.
In this paper, we employ a nonlinear adaptive mechanism to globally stabilize nth-order reactions.  相似文献   
84.
本文讨论了一种带有参考通道的自适应话音消噪滤波器原理,该滤波器采用最小均方差(心幅)算法。将此滤波器应用于复杂噪音背景的话音信号提取,能很好地抑制背景噪声,从而获得清晰的话音信号。  相似文献   
85.
Minimal inhibitory concentration (MIC), suspension and biofilm tests were used in evaluating the disinfecting efficacy of eight commercially available disinfectants and four chlorinated alkaline cleaners against 10 strains of Listeria monocytogenes at refrigerated temperatures. The adaptive response and cross-adaptation of L. monocytogenes to the disinfectants and chlorinated alkaline cleaners were investigated. The bactericidal components in the agents used were chlorine, quaternary ammonium compound (QAC), peracetic acid, ethanol and isopropanol. With some exceptions the disinfectants were efficient against the L. monocytogenes strains. One alkaline hypochlorite containing disinfectant was not efficient in the suspension and MIC tests at the lowest concentration recommended by the manufacturer. The chlorinated alkaline cleaners were effective against L. monocytogenes. A QAC-based disinfectant was found to be the least-effective agent on both glass bead-blasted polyethylene and stainless-steel surfaces. Adaptive and cross-adaptive responses of L. monocytogenes strains were observed towards the QAC-based agent, but over 2-fold increases to other agents were not observed. These results suggest that the adaptive responses of L. monocytogenes to disinfectants or chlorinated alkaline cleaners are of a minor concern.  相似文献   
86.
为了降低转子电阻变化对异步电动机矢量控制系统性能的影响,本文把自适应比例因子模糊控制器应用到了矢量控制系统中。介绍了自适应比例因子模糊控制方法的綦本原理,给出了使用自适应比例因子模糊控制器的异步电动机矢量控制系统的结构框图,对主模糊控制器和辅助模糊控制器进行了设计。仿真实验结果表明,采用这种控制方法的调速系统不仅具有优良的动态性能,而且对转子电阻变化具有很强的鲁棒性。  相似文献   
87.
陈维辉 《冶金设备》2003,(1):16-30,55
详细介绍了ZPG系列盘式真空过滤机的主要特点、基本原理和主要技术参数。对盘式真空过滤机的过滤理论进行了系统的研究 ,以及为提高过滤系数和降低滤饼水分所采取的关键措施。与传统的真空过滤机进行了对比 ,表明ZPG系列盘式真空过滤机的滤饼水分可以降低 1 %~ 3 % ,过滤系数提高 3 0 %~5 0 % ,过滤每吨精矿的能耗可以降低 5 0 %左右 ,使得ZPG系列盘式真空过滤机在国内各大冶金矿山得到全面推广使用 ,创造了巨大的经济效益和社会效益。  相似文献   
88.
This paper comes true a system of facial detection and location. Firstly, it realizes the facial detection of candidate region used skin color for the given image, and considers the influence of similar skin. Secondly, it realizes the location for eye region used the gray characteristic of eye and correction of central measurement, and makes further selection for facial candidate region. The end, it normalizes the facial image and makes it as front standard image, so realizes the facial characteristic location.  相似文献   
89.
90.
This paper is concerned with the achievable performance of adaptive control algorithms. We show that when the only uncertainty is in the form of fixed parameter errors, then there exists an adaptive feedback law whose performance can be made arbitrarily close to that achievable when the system is a priori known. The result is not intended as a practical strategy. Instead, we use it to make the, perhaps obvious, point that meaningful results on performance of adaptive control algorithms must account for non-ideal factors including, at a minimum, noise, parameter time variations and unstructured uncertainty.  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