全文获取类型
收费全文 | 566968篇 |
免费 | 6233篇 |
国内免费 | 1004篇 |
专业分类
电工技术 | 10510篇 |
综合类 | 466篇 |
化学工业 | 90095篇 |
金属工艺 | 23338篇 |
机械仪表 | 18508篇 |
建筑科学 | 12533篇 |
矿业工程 | 4313篇 |
能源动力 | 14436篇 |
轻工业 | 45766篇 |
水利工程 | 6943篇 |
石油天然气 | 14961篇 |
武器工业 | 39篇 |
无线电 | 60309篇 |
一般工业技术 | 116247篇 |
冶金工业 | 95580篇 |
原子能技术 | 14686篇 |
自动化技术 | 45475篇 |
出版年
2021年 | 5490篇 |
2019年 | 5269篇 |
2018年 | 9207篇 |
2017年 | 9415篇 |
2016年 | 9838篇 |
2015年 | 6029篇 |
2014年 | 10252篇 |
2013年 | 26119篇 |
2012年 | 15788篇 |
2011年 | 21099篇 |
2010年 | 16973篇 |
2009年 | 18829篇 |
2008年 | 19076篇 |
2007年 | 18783篇 |
2006年 | 16291篇 |
2005年 | 14753篇 |
2004年 | 14008篇 |
2003年 | 13697篇 |
2002年 | 13254篇 |
2001年 | 12852篇 |
2000年 | 12332篇 |
1999年 | 12012篇 |
1998年 | 27652篇 |
1997年 | 20045篇 |
1996年 | 15629篇 |
1995年 | 12007篇 |
1994年 | 10862篇 |
1993年 | 10614篇 |
1992年 | 8336篇 |
1991年 | 8106篇 |
1990年 | 7994篇 |
1989年 | 7766篇 |
1988年 | 7482篇 |
1987年 | 6748篇 |
1986年 | 6535篇 |
1985年 | 7390篇 |
1984年 | 6700篇 |
1983年 | 6437篇 |
1982年 | 5777篇 |
1981年 | 5899篇 |
1980年 | 5631篇 |
1979年 | 5736篇 |
1978年 | 5663篇 |
1977年 | 6179篇 |
1976年 | 7686篇 |
1975年 | 5108篇 |
1974年 | 4903篇 |
1973年 | 4981篇 |
1972年 | 4279篇 |
1971年 | 4040篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
61.
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
62.
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
63.
64.
Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 95–112, March–April, 1994. 相似文献
65.
66.
A. G. Strunina 《Journal of Engineering Physics and Thermophysics》1993,65(4):953-956
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
67.
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
68.
Furst C. Leitenstorfer A. Laubereau A. 《IEEE journal of selected topics in quantum electronics》1996,2(3):473-479
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
69.
70.