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   436篇
  免费   27篇
  国内免费   36篇
电工技术   15篇
综合类   15篇
化学工业   70篇
金属工艺   24篇
机械仪表   14篇
建筑科学   18篇
矿业工程   12篇
能源动力   9篇
轻工业   17篇
水利工程   1篇
石油天然气   20篇
武器工业   1篇
无线电   82篇
一般工业技术   59篇
冶金工业   35篇
原子能技术   36篇
自动化技术   71篇
  2023年   3篇
  2022年   11篇
  2021年   17篇
  2020年   14篇
  2019年   6篇
  2018年   4篇
  2017年   18篇
  2016年   17篇
  2015年   25篇
  2014年   10篇
  2013年   14篇
  2012年   15篇
  2011年   14篇
  2010年   17篇
  2009年   21篇
  2008年   20篇
  2007年   22篇
  2006年   13篇
  2005年   12篇
  2004年   7篇
  2003年   8篇
  2002年   7篇
  2001年   8篇
  2000年   13篇
  1999年   12篇
  1998年   12篇
  1997年   13篇
  1996年   19篇
  1995年   9篇
  1994年   22篇
  1993年   18篇
  1992年   13篇
  1991年   8篇
  1990年   11篇
  1989年   7篇
  1988年   2篇
  1987年   6篇
  1986年   4篇
  1985年   4篇
  1982年   4篇
  1981年   2篇
  1980年   1篇
  1978年   1篇
  1977年   3篇
  1976年   4篇
  1975年   1篇
  1974年   1篇
  1972年   2篇
  1968年   2篇
  1964年   1篇
排序方式: 共有499条查询结果,搜索用时 15 毫秒
1.
2.
A light-induced excited spin state trapping (LIESST) experiment for a thermal gradual spin crossover complex, Fetris (2-pyridylmethyl) amine(NCS)2 or Fe(tpa) (NCS)2, was attempted for the first time. The high spin (HS) state after light inducement stayed metastable over a period of days without relaxation at 10 K. Intersystem relaxation from a high to a low spin (LS) complex occurred at 50 K after bleaching at 10 K. Investigation of the Mossbauer spectra of the LIESST and relaxation experiment indicated that the Debye–Waller factor was a correlation parameter of the HS fraction and that the co-operative effect played a role in the relaxation process for such a solid compound. This revised version was published online in November 2006 with corrections to the Cover Date.  相似文献   
3.
Neural network impedance force control of robot manipulator   总被引:1,自引:0,他引:1  
The performance of an impedance controller for robot force tracking is affected by the uncertainties in both the robot dynamic model and environment stiffness. The purpose of this paper is to improve the controller robustness by applying the neural network (NN) technique to compensate for the uncertainties in the robot model. NN control techniques are applied to two impedance control methods: torque-based and position-based impedance control, which are distinguished by the way of the impedance functions being implemented. A novel error signal is proposed for the NN training. In addition, a trajectory modification algorithm is developed to determine the reference trajectory when the environment stiffness is unknown. The robustness analysis of this algorithm to force sensor noise and inaccurate environment position measurement is also presented. The performances of the two NN impedance control schemes are compared by computer simulations. Simulation results based on a three-degrees-of-freedom robot show that highly robust position/force tracking can be achieved in the presence of large uncertainties and force sensor noise  相似文献   
4.
Three sub-25 nm fly height sliders are presented for near contact recording. The designs are geared towards the goal of achieving 10 Gb/in 2 areal density. The optimization procedure presented shows promise for facilitating achievement of this goal. The dynamic simulations show the stability of these designs when disturbed from their steady state conditions  相似文献   
5.
The robust controller has very simple structures and can be divided into two separate parts: a servo controller and an auxiliary controller. The two controllers are designed independently. The function of the auxiliary controller is to cancel out the plant uncertainties directly without the use of the high loop gain principle. Interpretation of robot controller as a signal-synthesis adaptive controller is given. Practical implementation issues of the auxiliary controller are discussed. Simulations of a design example with large parameter uncertainty, nonlinearity, and external disturbance are presented to demonstrate the effectiveness of the design technique. This technique is further tested with success in an experimental study of joint position control of a PUMA 560 robot arm  相似文献   
6.
This paper presents a cost-effective 2-D-discrete cosine transform (DCT) architecture based on the fast row/column decomposition algorithm. We propose a new schedule for 2-D-DCT computing to reduce the hardware cost. With this approach, the transposed memory can be simplified using shift-registers for the data transposition between two 1-D-DCT units. A special shift cell with MOS circuit is designed by using the energy transferring methodology. The memory size can be greatly reduced, and the address generator and its READ/WRITE control all can be saved. For an 8 times 8-block transformation, the number of transistors is only 4 k for the shift-register array. The maximum frequency of shift-operation can achieve about 120 MHz, when implemented by 0.35-mum technology.  相似文献   
7.
8.
辉锑矿矿浆电解浸出机理的研究   总被引:3,自引:0,他引:3  
研究了辉锑矿矿浆电解阳极室浸出反应机理.结果表明,辉锑矿的溶解符合核收缩模型的动力学规律,浸出速率受混合过程控制,表观活化能为25.10KJ/mol.浸出主反应是辉锑矿被阳极上析出的氯氧化,SCl2是氧化反应的中间产物.  相似文献   
9.
The differences between ITS-90 and IPTS-68 above 1235 K are described. It is shown that none of the following CIE definitions or recommendations require revision because of the introduction of the ITS-90: International Lighting Vocabulary definitions; CIE Standard Illuminants A, D65, other illuminants; and sources for realizing CIE Illuminants. The effect of the ITS-90 on previously calibrated sources for realizing CIE illuminants is negligibly small.2  相似文献   
10.
目前,电网设备管理大多通过被动的计划检修完成,只注重遵循相关运维规程按设备运行时间安排检修工作,忽略对设备全寿命健康状况的评估与管理。本文提出计及设备全寿命周期运行状态的多源融合主动资产管理方法。首先,根据资产时间、逻辑及历史知识提出全寿命周期三维资产管理模型。接着采用设备案例推理方法,从电网安全、稳定、经济运行角度,应用迁移学习方法对案例进行自学习与案例库强化。最后,将所提出方法应用于存在海量多源异构数据的设备全寿命周期主动管理的实际案例中。结果表明,主动资产管理可以有效自动辨识设备运维状态,保证资产管理策略的可行性、适用性及安全性,为运维人员提供有力辅助决策。  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