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   866篇
  免费   46篇
  国内免费   1篇
电工技术   4篇
化学工业   218篇
金属工艺   6篇
机械仪表   29篇
建筑科学   34篇
矿业工程   1篇
能源动力   26篇
轻工业   90篇
水利工程   3篇
石油天然气   3篇
无线电   69篇
一般工业技术   180篇
冶金工业   98篇
原子能技术   19篇
自动化技术   133篇
  2024年   1篇
  2023年   4篇
  2022年   31篇
  2021年   63篇
  2020年   30篇
  2019年   44篇
  2018年   34篇
  2017年   27篇
  2016年   34篇
  2015年   20篇
  2014年   47篇
  2013年   55篇
  2012年   48篇
  2011年   75篇
  2010年   40篇
  2009年   38篇
  2008年   34篇
  2007年   25篇
  2006年   20篇
  2005年   21篇
  2004年   13篇
  2003年   9篇
  2002年   14篇
  2001年   11篇
  2000年   12篇
  1999年   9篇
  1998年   24篇
  1997年   25篇
  1996年   18篇
  1995年   5篇
  1994年   10篇
  1993年   9篇
  1992年   9篇
  1991年   4篇
  1990年   3篇
  1989年   6篇
  1988年   6篇
  1987年   3篇
  1986年   5篇
  1985年   5篇
  1984年   5篇
  1983年   4篇
  1982年   2篇
  1981年   3篇
  1980年   2篇
  1977年   2篇
  1976年   2篇
  1974年   1篇
  1926年   1篇
排序方式: 共有913条查询结果,搜索用时 312 毫秒
71.
It is well documented that the processing of social and emotional information is impaired in people with autism. Recent studies have shown that individuals, particularly those with high functioning autism, can learn to cope with common social situations if they are made to enact possible scenarios they may encounter in real life during therapy. The main aim of this work is to describe an interactive life-like facial display (FACE) and a supporting therapeutic protocol that will enable us to verify if the system can help children with autism to learn, identify, interpret, and use emotional information and extend these skills in a socially appropriate, flexible, and adaptive context. The therapeutic setup consists of a specially equipped room in which the subject, under the supervision of a therapist, can interact with FACE. The android display and associated control system has automatic facial tracking, expression recognition, and eye tracking. The treatment scheme is based on a series of therapist-guided sessions in which a patient communicates with FACE through an interactive console. Preliminary data regarding the exposure to FACE of two children are reported.  相似文献   
72.
73.
74.
In this paper we report the accuracy evaluation of the Italian primary frequency standard IEN-CsF1. We discuss the shifts the frequency standard is corrected for and the procedure used for the accuracy evaluation. In the last section we report frequency comparisons of our fountain with those of remote laboratories and with International Atomic Time.  相似文献   
75.
A new, simple device generates accurate nano- and microflow rate gradients from any conventional HPLC system. The core of the new device is represented by an electric-actuated, computer-controlled, multiposition HPLC valve. The valve hosts six reservoirs for as many different mobile-phase compositions of increasing strength. A low flow rate stream pushes the weakest solvent through the column as long as required and at the desired flow rate, until the chromatographic run is started. From this time on, the electric actuation allows one to select which reservoir will be on-line with the column and for how long, thus generating a specific solvent gradient, through a sequence of controlled segments of precise mobile-phase composition. This permits one not only to exactly reproduce the programmed slope but also to achieve different gradient shapes (i.e., linear, convex, concave) for different separation needs. The new device has proven to be reliable and reproducible even at the lowest flow rate tested (250 nL x min(-1)) and in different chromatographic conditions.  相似文献   
76.
77.
In this paper, we describe a new technique for automatic phase stepping in fiber-optic Electronic Speckle Pattern Interferometry (ESPI), useful in both single-point and imaging configurations. The proposed technique is based on closed-loop switching of the gain sign in the control loop used to stabilize the reference wavefront phase, with the aid of a Proportional-Integral (P.I.) controller. Simulation and experimental results are compared, showing that by a synchronization signal or by a proper choice of the feedback loop parameters, a sequence of π/2 steps of the reference wavefront phase, all of the same sign, is obtained, The residual fluctuation of each phase step amounts to ±2.5 mr over a bandwidth of 200 Hz. This level of phase stability is well suited for ESPI applications  相似文献   
78.
We investigate the electronic transport properties of Cu(In,Ga)Se2 solar cells by means of quantum efficiency and temperature dependent admittance spectroscopy. A simple evaluation scheme of quantum efficiency data is introduced which accounts for recombinatoric losses in the Us buffer layer and in the Cu(In,Ga)Se2 absorber. By admittance spectroscopy, we find that the controlled incorporation of Na into the absorber material leads to a shallow acceptor state at about 75 meV above the valence band.  相似文献   
79.
The present study analyzes the electromagnetic interference produced on visual display units (VDUs) in domestic and industrial environments. The main sources of disturbance may be identified in three-phase lines, unbalanced currents, currents in earthing systems, proximity of power installations, proximity of railway tracks, and presence of harmonics on the neutral conductor. Magnetic-field interference for PCs is practically limited to the deflection of the cathode-ray tube (CRT) electron beam. The vertical magnetic field determines a horizontal electron beam motion. The distortion depends linearly on magnetic field intensity and on the difference between the frequency of the CRT vertical raster scan and the frequency of the interfering magnetic field. Herein are analyzed two actual cases of interference produced by the DC-supply line of a metropolitan tram network and by the public electric power distribution network.  相似文献   
80.
Interactions between methoxybutropate and β-cyclodextrin or hydroxypropyl β-cyclodextrin and the possibility of obtaining inclusion complexes have been evaluated by phase solubility diagram, HPLC, DSC, and x-ray diffractometry. Solid inclusion complexes were prepared by spray drying, kneading, and solid dispersion. The dissolution profiles of the obtained powders were studied in order to define the most appropriate cyclodextrin preparation method and molar ratio to use in the production of methoxybutropate inclusion complexes  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