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   867193篇
  免费   10472篇
  国内免费   2235篇
电工技术   15995篇
综合类   769篇
化学工业   134574篇
金属工艺   33945篇
机械仪表   26876篇
建筑科学   21330篇
矿业工程   4983篇
能源动力   22333篇
轻工业   75040篇
水利工程   9255篇
石油天然气   16387篇
武器工业   52篇
无线电   99086篇
一般工业技术   170343篇
冶金工业   154942篇
原子能技术   18474篇
自动化技术   75516篇
  2021年   7315篇
  2019年   6989篇
  2018年   11872篇
  2017年   12122篇
  2016年   12811篇
  2015年   8533篇
  2014年   14191篇
  2013年   40344篇
  2012年   22693篇
  2011年   31244篇
  2010年   24890篇
  2009年   27810篇
  2008年   28785篇
  2007年   28680篇
  2006年   25192篇
  2005年   22937篇
  2004年   22172篇
  2003年   21628篇
  2002年   20910篇
  2001年   20570篇
  2000年   19426篇
  1999年   19708篇
  1998年   45588篇
  1997年   33207篇
  1996年   25984篇
  1995年   20158篇
  1994年   18118篇
  1993年   17627篇
  1992年   13519篇
  1991年   12957篇
  1990年   12729篇
  1989年   12301篇
  1988年   11810篇
  1987年   10411篇
  1986年   10172篇
  1985年   11942篇
  1984年   11026篇
  1983年   10087篇
  1982年   9259篇
  1981年   9298篇
  1980年   8883篇
  1979年   8931篇
  1978年   8628篇
  1977年   9825篇
  1976年   12700篇
  1975年   7578篇
  1974年   7248篇
  1973年   7209篇
  1972年   6117篇
  1971年   5599篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
101.
The capacitive idling converters derived from the Cuk, SEPIC, Zeta, and flyback topologies allow soft commutation of power switches without the need for additional circuitry, making it possible to increase the switching frequency while maintaining high efficiency  相似文献   
102.
Canny  J. 《Computer Journal》1993,36(5):409-418
  相似文献   
103.
Pipelining and bypassing in a VLIW processor   总被引:1,自引:0,他引:1  
This short note describes issues involved in the bypassing mechanism for a very long instruction word (VLIW) processor and its relation to the pipeline structure of the processor. The authors first describe the pipeline structure of their processor and analyze its performance and compare it to typical RISC-style pipeline structures given the context of a processor with multiple functional units. Next they study the performance effects of various bypassing schemes in terms of their effectiveness in resolving pipeline data hazards and their effect on the processor cycle time  相似文献   
104.
105.
106.
Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 95–112, March–April, 1994.  相似文献   
107.
The study presents a hypothesis on how randomness could be simulated by human subjects. Three sources of deviation from randomness are predicted: (1) the preferred application of overlearned production schemata for producing sequences of digits, (2) a wrong concept of randomness, and (3) the impossibility to monitor for redundancies of higher- than those of first-order. Deviations of random generation of digits produced by healthy subjects, patients with chronic frontal lobe damage, and patients with Parkinson's disease from random sequences produced by a computer program can be explained by the differential influence of these factors. Whereas incorrect concepts of randomness and limits on monitoring capacity distinguished all sequences produced by humans from actual random sequences, persistence on a single production strategy distinguished brain-damaged patients from controls. Random generation of digits appears to be a theoretically transparent and clinically useful test of executive function.  相似文献   
108.
109.
The process of combustion of homogeneous and heterogeneous nongasifying and slightly gasifying systems over the range of a number of parameters characterizing the reactive composition and the conditions for the arrangement of the combustion process is studied by using thermocouple and optical methods. The regions of the implementation of different combustion regimes, namely, steady, pulsating, multiple-point, and spin, are determined experimentally.Institute of Structural Macrokinetics, Russian Academy of Sciences, Chernogolovka. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No. 4, pp. 407–411, October, 1993.  相似文献   
110.
An extended logistic model with a varying asymptotic upper bound for long-range peak demand forecasting is described. The model has been applied to a typical fast growing system, the Saudi Consolidated Electric Company. The forecasts are compared with actual demands and with those obtained from classical forecasting methods. The model gave relatively accurate peak demand forecasts compared with other classical methods. The model with a single load observation is capable of producing several peak demand forecasts corresponding to different levels of maximum temperature and various levels of social activity. The forecasts produced by the model were also stable irrespective of the length of the ex-post simulation period  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