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   570074篇
  免费   6292篇
  国内免费   1007篇
电工技术   10546篇
综合类   470篇
化学工业   90772篇
金属工艺   23402篇
机械仪表   18573篇
建筑科学   12664篇
矿业工程   4323篇
能源动力   14510篇
轻工业   45999篇
水利工程   6961篇
石油天然气   14971篇
武器工业   39篇
无线电   60592篇
一般工业技术   116765篇
冶金工业   96108篇
原子能技术   14710篇
自动化技术   45968篇
  2021年   5513篇
  2019年   5300篇
  2018年   9253篇
  2017年   9446篇
  2016年   9883篇
  2015年   6068篇
  2014年   10331篇
  2013年   26290篇
  2012年   15892篇
  2011年   21242篇
  2010年   17075篇
  2009年   18940篇
  2008年   19224篇
  2007年   18893篇
  2006年   16416篇
  2005年   14857篇
  2004年   14101篇
  2003年   13771篇
  2002年   13338篇
  2001年   12900篇
  2000年   12389篇
  1999年   12074篇
  1998年   27770篇
  1997年   20111篇
  1996年   15694篇
  1995年   12064篇
  1994年   10899篇
  1993年   10661篇
  1992年   8370篇
  1991年   8148篇
  1990年   8034篇
  1989年   7793篇
  1988年   7513篇
  1987年   6785篇
  1986年   6588篇
  1985年   7428篇
  1984年   6740篇
  1983年   6477篇
  1982年   5814篇
  1981年   5943篇
  1980年   5669篇
  1979年   5773篇
  1978年   5699篇
  1977年   6217篇
  1976年   7719篇
  1975年   5141篇
  1974年   4925篇
  1973年   5003篇
  1972年   4302篇
  1971年   4061篇
排序方式: 共有10000条查询结果,搜索用时 15 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