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   568401篇
  免费   6272篇
  国内免费   1008篇
电工技术   10528篇
综合类   467篇
化学工业   90384篇
金属工艺   23360篇
机械仪表   18524篇
建筑科学   12641篇
矿业工程   4315篇
能源动力   14499篇
轻工业   45842篇
水利工程   6954篇
石油天然气   14973篇
武器工业   39篇
无线电   60439篇
一般工业技术   116464篇
冶金工业   95769篇
原子能技术   14687篇
自动化技术   45796篇
  2021年   5506篇
  2019年   5287篇
  2018年   9230篇
  2017年   9440篇
  2016年   9862篇
  2015年   6065篇
  2014年   10304篇
  2013年   26221篇
  2012年   15853篇
  2011年   21202篇
  2010年   17050篇
  2009年   18903篇
  2008年   19157篇
  2007年   18842篇
  2006年   16375篇
  2005年   14816篇
  2004年   14090篇
  2003年   13749篇
  2002年   13302篇
  2001年   12874篇
  2000年   12355篇
  1999年   12039篇
  1998年   27671篇
  1997年   20055篇
  1996年   15657篇
  1995年   12028篇
  1994年   10876篇
  1993年   10634篇
  1992年   8355篇
  1991年   8118篇
  1990年   7999篇
  1989年   7780篇
  1988年   7480篇
  1987年   6758篇
  1986年   6540篇
  1985年   7403篇
  1984年   6714篇
  1983年   6441篇
  1982年   5788篇
  1981年   5903篇
  1980年   5637篇
  1979年   5745篇
  1978年   5670篇
  1977年   6183篇
  1976年   7696篇
  1975年   5113篇
  1974年   4908篇
  1973年   4983篇
  1972年   4283篇
  1971年   4041篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
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   
62.
63.
Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 95–112, March–April, 1994.  相似文献   
64.
65.
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   
66.
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   
67.
An experimental and theoretical analysis of the nonlinear coupling mechanism between the two solitary pulses circulating in a two-color femtosecond laser is presented. Two operation regimes; synchronized; and nonsynchronized; and a hysteresis of the transition between the two regimes are clearly observed; while independent modelocking and tunability of the output pulse trains is found in both regimes. Pulses in the range from 15 to 100 fs are synchronized with a timing jitter below 2 fs. The combined effects of cross-phase modulation and negative group velocity dispersion are shown to be responsible for the strong pulse correlation in the synchronized regime. Our experimental observations are in agreement with numerical simulations, thus confirming the theoretical model  相似文献   
68.
69.
70.
A systematic and straightforward procedure is developed for the synthesis and analysis of transformer-isolated power converters. The procedure can be used to determine the ranges of duty-ratio over which the transformer-isolated power converters of a given class can be operated without transformer saturation. The procedure can also be used to study the dependence of the power converter switch stresses on duty-ratios. This information is useful in the selection of the transformer-isolated power converter most suitable for a given application and in the design of this power converter with minimum switch stresses, high power density, and low cost  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