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   570535篇
  免费   6466篇
  国内免费   1014篇
电工技术   10530篇
综合类   467篇
化学工业   91249篇
金属工艺   23410篇
机械仪表   18605篇
建筑科学   12634篇
矿业工程   4318篇
能源动力   14538篇
轻工业   46561篇
水利工程   6981篇
石油天然气   14974篇
武器工业   39篇
无线电   60452篇
一般工业技术   116698篇
冶金工业   95901篇
原子能技术   14697篇
自动化技术   45961篇
  2021年   5742篇
  2020年   4157篇
  2019年   5450篇
  2018年   9375篇
  2017年   9579篇
  2016年   10004篇
  2015年   6165篇
  2014年   10406篇
  2013年   26368篇
  2012年   16009篇
  2011年   21317篇
  2010年   17153篇
  2009年   19024篇
  2008年   19236篇
  2007年   18899篇
  2006年   16401篇
  2005年   14836篇
  2004年   14071篇
  2003年   13746篇
  2002年   13297篇
  2001年   12897篇
  2000年   12366篇
  1999年   12051篇
  1998年   27740篇
  1997年   20100篇
  1996年   15678篇
  1995年   12037篇
  1994年   10889篇
  1993年   10636篇
  1992年   8349篇
  1991年   8110篇
  1990年   8000篇
  1989年   7777篇
  1988年   7487篇
  1987年   6756篇
  1986年   6539篇
  1985年   7397篇
  1984年   6711篇
  1983年   6439篇
  1982年   5779篇
  1981年   5898篇
  1980年   5633篇
  1979年   5737篇
  1978年   5663篇
  1977年   6180篇
  1976年   7694篇
  1975年   5110篇
  1974年   4907篇
  1973年   4981篇
  1972年   4283篇
排序方式: 共有10000条查询结果,搜索用时 46 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