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   6507篇
  免费   315篇
  国内免费   17篇
电工技术   73篇
综合类   7篇
化学工业   1534篇
金属工艺   107篇
机械仪表   148篇
建筑科学   327篇
矿业工程   9篇
能源动力   226篇
轻工业   540篇
水利工程   61篇
石油天然气   26篇
武器工业   2篇
无线电   581篇
一般工业技术   1108篇
冶金工业   913篇
原子能技术   34篇
自动化技术   1143篇
  2023年   67篇
  2022年   107篇
  2021年   173篇
  2020年   123篇
  2019年   125篇
  2018年   175篇
  2017年   157篇
  2016年   192篇
  2015年   160篇
  2014年   223篇
  2013年   407篇
  2012年   366篇
  2011年   428篇
  2010年   325篇
  2009年   369篇
  2008年   353篇
  2007年   367篇
  2006年   262篇
  2005年   253篇
  2004年   204篇
  2003年   183篇
  2002年   157篇
  2001年   105篇
  2000年   111篇
  1999年   107篇
  1998年   103篇
  1997年   111篇
  1996年   80篇
  1995年   100篇
  1994年   87篇
  1993年   63篇
  1992年   64篇
  1991年   31篇
  1990年   46篇
  1989年   65篇
  1988年   49篇
  1987年   37篇
  1986年   51篇
  1985年   57篇
  1984年   44篇
  1983年   54篇
  1982年   35篇
  1981年   35篇
  1980年   32篇
  1979年   26篇
  1978年   19篇
  1977年   17篇
  1976年   24篇
  1975年   29篇
  1974年   22篇
排序方式: 共有6839条查询结果,搜索用时 15 毫秒
121.
122.
123.
Several results in coding theory (e.g. the Carlitz-Uchiyama bound) show that the weight distributions of certain algebraic codes of lengthn are concentrated aroundn/2 within a range of width n. It is proved in this article that the extreme weights of a linear binary code of sufficiently high dual distance cannot be too close ton/2, the gap being of order n. The tools used involve the Pless identities and the orthogonality properties of Krawtchouk polynomials, as well as estimates on their zeroes. As a by-product upper bounds on the minimum distance of self-dual binary codes are derived.  相似文献   
124.
This paper introduces time stream Pétri nets (Ts treamPn), a model for the formal specification of multimedia synchronization scenarios. This new model extends time Pétri nets to formally describe the timed behaviour of multimedia objects and streams in asynchronous distributed systems. The proposed approach uses time intervals to label the arcs exiting from the places of the net, and typed transitions to define different firing rules. This model allows a complete and accurate specification of synchronization constraints between multimedia streams and can be used at different levels of granularity.  相似文献   
125.
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   
126.
Active matrix prestressed microelectromechanical shutter displays enable outstanding optical properties as well as robust operating performance. The microelectromechanical systems (MEMS) shutter elements have been optimized for higher light outcoupling efficiency with lower operation voltage and higher pixel density. The MEMS elements have been co-fabricated with self-aligned metal-oxide thin-film transistors (TFTs). Several optimizations were required to integrate MEMS process without hampering the performance of both elements. The optimized display process requires only seven photolithographic masks with ensuring proper compatibility between MEMS shutter and metal-oxide TFT process.  相似文献   
127.
Journal of Signal Processing Systems - This paper describes a field-programmable gate array (FPGA) implementation of a fixed-point low-density lattice code (LDLC) decoder where the Gaussian mixture...  相似文献   
128.
Journal of Logic, Language and Information -  相似文献   
129.
A thermal model was built to account for the effects of geometrical parameters of sheet specimen, process parameters and material parameters on the temperature increase of the sheet specimen in Electricity-Assisted Incremental Sheet Forming (EISF). In the EISF, the local area of sheet specimen contacting with a forming tool is heated by direct current, which flows through the forming tool to the sheet specimen. EISF experiments of two high strength steel sheets were carried out to validate the thermal model. The thermal model can be integrated into the control program of EISF system to achieve more accurate temperature control.  相似文献   
130.
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