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   706997篇
  免费   7830篇
  国内免费   1550篇
电工技术   13393篇
综合类   560篇
化学工业   108049篇
金属工艺   28280篇
机械仪表   22143篇
建筑科学   15526篇
矿业工程   4732篇
能源动力   17869篇
轻工业   55341篇
水利工程   8068篇
石油天然气   16198篇
武器工业   45篇
无线电   79943篇
一般工业技术   142145篇
冶金工业   130313篇
原子能技术   16762篇
自动化技术   57010篇
  2021年   6309篇
  2020年   4678篇
  2019年   6103篇
  2018年   10497篇
  2017年   10670篇
  2016年   11194篇
  2015年   7043篇
  2014年   11957篇
  2013年   31874篇
  2012年   18593篇
  2011年   25179篇
  2010年   20248篇
  2009年   22797篇
  2008年   23279篇
  2007年   23019篇
  2006年   20165篇
  2005年   18379篇
  2004年   17705篇
  2003年   17272篇
  2002年   16739篇
  2001年   16588篇
  2000年   15764篇
  1999年   16005篇
  1998年   39502篇
  1997年   27902篇
  1996年   21540篇
  1995年   16379篇
  1994年   14615篇
  1993年   14399篇
  1992年   10725篇
  1991年   10433篇
  1990年   10241篇
  1989年   9948篇
  1988年   9413篇
  1987年   8327篇
  1986年   8210篇
  1985年   9310篇
  1984年   8358篇
  1983年   7889篇
  1982年   7146篇
  1981年   7381篇
  1980年   6918篇
  1979年   6923篇
  1978年   6811篇
  1977年   7664篇
  1976年   9746篇
  1975年   6070篇
  1974年   5847篇
  1973年   5859篇
  1972年   5066篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
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   
82.
83.
Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 95–112, March–April, 1994.  相似文献   
84.
Variations in lipid profile and incidence of vascular events were evaluated. Group 1 had a 29.3% reduction of total and a 38.3% reduction of LDL cholesterol as against reductions of 9% and 9.6% respectively in group 2. No significant difference was observed between the two groups as far as the vascular events considered were concerned. Pravastatin is an effective and safe drug. The lack of influence on the evolution of vascular disease would appear to be correlated to the small number of subjects studied and the short follow-up.  相似文献   
85.
86.
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   
87.
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   
88.
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   
89.
90.
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