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   3092篇
  免费   90篇
  国内免费   70篇
电工技术   27篇
综合类   89篇
化学工业   498篇
金属工艺   336篇
机械仪表   350篇
建筑科学   233篇
矿业工程   39篇
能源动力   90篇
轻工业   48篇
水利工程   27篇
石油天然气   26篇
武器工业   8篇
无线电   202篇
一般工业技术   664篇
冶金工业   114篇
原子能技术   45篇
自动化技术   456篇
  2024年   2篇
  2023年   37篇
  2022年   29篇
  2021年   50篇
  2020年   58篇
  2019年   49篇
  2018年   43篇
  2017年   53篇
  2016年   65篇
  2015年   89篇
  2014年   121篇
  2013年   159篇
  2012年   156篇
  2011年   243篇
  2010年   170篇
  2009年   196篇
  2008年   156篇
  2007年   164篇
  2006年   170篇
  2005年   138篇
  2004年   123篇
  2003年   180篇
  2002年   121篇
  2001年   87篇
  2000年   86篇
  1999年   80篇
  1998年   77篇
  1997年   59篇
  1996年   43篇
  1995年   50篇
  1994年   28篇
  1993年   20篇
  1992年   23篇
  1991年   22篇
  1990年   9篇
  1989年   16篇
  1988年   9篇
  1987年   12篇
  1986年   5篇
  1985年   8篇
  1984年   14篇
  1983年   7篇
  1982年   6篇
  1981年   2篇
  1972年   2篇
  1966年   3篇
  1961年   1篇
  1958年   1篇
  1956年   2篇
  1955年   1篇
排序方式: 共有3252条查询结果,搜索用时 62 毫秒
71.
In this work, real-time ultraviolet photodetectors are realized through metal–semiconductor–metal (MSM) structures. Amorphous indium gallium zinc oxide (a-IGZO) is used as semiconductor material and gold as metal electrodes. The readout of an individual sensor is implemented by a transimpedance amplifier (TIA) consisting of an all-enhancement a-IGZO thin-film transistor (TFT) operational amplifier and a switched capacitor (SC) as feedback resistance. The photosensor and the transimpedance amplifier are both manufactured on glass substrates. The measured photosensor possesses a high responsivity R , a low response time t R E S , and a good noise equivalent power value NEP .  相似文献   
72.
Abstract— The current status of AC powder electroluminescent (ACPEL) displays is reviewed with particular emphasis given to color and lifetime. The printing of the displays in forward and reverse architectures is also discussed, in addition to the fabrication of ACPEL displays with interdigitated electrodes, and different types of ACPEL phosphors and materials for back electrodes, transparent conducting electrodes, binders, and dielectrics are considered. Furthermore, shape conformable and highly flexible ACPEL displays are surveyed.  相似文献   
73.
Abstract— A processing technology based upon a temporary bond—debond approach has been developed that enables direct fabrication of high‐performance electronic devices on flexible substrates. This technique facilitates processing of flexible plastic and metal‐foil substrates through automated standard semiconductor and flat‐panel tool sets without tool modification. The key to processing with these tool sets is rigidifying the flexible substrates through temporary bonding to carriers that can be handled in a similar manner as silicon wafers or glass substrates in conventional electronics manufacturing. To demonstrate the power of this processing technology, amorphous‐silicon thin‐film‐transistor (a‐Si:H TFT) backplanes designed for electrophoretic displays (EPDs) were fabricated using a low‐temperature process (180°C) on bonded‐plastic and metal‐foil substrates. The electrical characteristics of the TFTs fabricated on flexible substrates are found to be consistent with those processed with identical conditions on rigid silicon wafers. These TFTs on plastic exhibit a field‐effect mobility of 0.77 cm2/V‐sec, on/off current ratio >109 at Vds = 10 V, sub‐threshold swing of 365 mV/dec, threshold voltage of 0.49 V, and leakage current lower than 2 pA/μm gate width. After full TFT‐array fabrication on the bonded substrate and subsequent debonding, the flexible substrate retains its original flexibility; this enables bending of the EPD display without loss in performance.  相似文献   
74.
Abstract— The development of a compact, efficient VGA projection module to be embedded in mobile devices is reported. The design incorporates laser/laser diode (LD) light sources, Schlieren optics, and a one‐dimensional diffractive spatial optical modulator (SOM). During development, the optical parameters were determined and the relationships between the parameters to optimize the optical specifications were derived. The resulting optimized specifications enable us to manufacture two types of optical modu les as compact as 13 cc and with as little as 10% speckle contrast ratio.  相似文献   
75.
Abstract— It is expected that 3‐D will be the next step in the enhanced viewing experience. At present, there are two competing 3‐D technologies for glasses‐based consumer TVs: active shutter glasses and passive polarized glasses. With the ongoing reduction in response time of liquid‐crystal displays (LCDs), this article will focus on shutter‐glass‐based stereoscopic LCDs. In this paper, the properties of such a display system is described and it is demonstrated that by adding a line‐scanning backlight, the cross‐talk can be reduced to less than 1.4%, allowing for excellent 3‐D portrayal. For images of extreme contrast, this is perceivable, but not judged annoying by a panel of expert viewers. Which characteristics of the display and shutter glasses that should be optimized to create an inexpensive, cross‐talk‐free, 3‐D LCD are discussed.  相似文献   
76.
袁盛和 《自动化信息》2010,(10):67-68,66
本文主要介绍了台达机电产品(触摸屏、PLC、变频器、温控器等)在塑料薄膜生产线上的整合应用。该控制系统操作界面友好简单,结合台达HMI、PLC和变频器等工控产品,实现了设备的技术升级与高效节能,体现出台达自动化产品较高的性价比。运行实践证明,台达产品稳定可靠,控制效率高,值得业界同行借鉴和推广。  相似文献   
77.
A robust projector–camera interactive display system consisting of one camera and one projector is proposed, which enables users to interact with computer by touching on arbitrary surfaces with bare hand. The system utilizes the camera to recover 3D information of fingertip for touch detection. Firstly, predicted image generated from geometric and photometric calibration matrix is used to segment hand and its shadow. Secondly, fusion degree of the hand and its shadow is detected using linear‐scanning method. Finally, a square tracking mask is used to determine the touch action on the projection surface. Experimental results show that the proposed system is robust to different lighting conditions. The touch detection accuracy is 93.0% and the average processing time of each frame is 36 ms.  相似文献   
78.
光学透视头盔显示器(OSTHMD)标定是增强现实技术研究中一个具有挑战性的关键技术问题. 研究了OSTHMD标定的几种常见技术及其优缺点, 详细论述了当前最常用的OSTHMD标定法: SPAAM法, 同时提出了一种基于图像的快速标定OSTHMD的方法, 从算法复杂度方面对两种标定法进行了对比, 并采用用户自行评估法进行评估, 认为基于图像的快速标定OSTHMD的方法更为快速精准.  相似文献   
79.
面向ASP模式的塑料注射成型CAE系统   总被引:2,自引:0,他引:2  
随着Internet和电子商务的迅猛发展,一种应用软件的新模式:ASP也逐渐凸现。文章构造了一个面向ASP基于Web的远程塑料注射成型CAE系统,详细介绍了系统的构造方法和关键技术。  相似文献   
80.
Decision rules have been developed and applied to the bills of materials of a color cathode‐ray tube (CRT) and a liquid‐crystal‐display (LCD) desktop monitor to determine which product and process materials will be evaluated in an environmental life‐cycle assessment. Materials of significant mass, of technological importance, and of potential environmental impact are targeted. The list of materials identified are those for which life‐cycle inventory data will be obtained for the materials extraction and materials processing life‐cycle stages of a CRT and an LCD. Additionally, materials identified will also be used to represent life‐cycle impact in terms of resource consumption, as well as surrogates for occupational health impacts.  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