全文获取类型
收费全文 | 4967篇 |
免费 | 347篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 52篇 |
综合类 | 1篇 |
化学工业 | 1149篇 |
金属工艺 | 118篇 |
机械仪表 | 198篇 |
建筑科学 | 195篇 |
矿业工程 | 10篇 |
能源动力 | 310篇 |
轻工业 | 777篇 |
水利工程 | 23篇 |
石油天然气 | 27篇 |
无线电 | 557篇 |
一般工业技术 | 905篇 |
冶金工业 | 187篇 |
原子能技术 | 36篇 |
自动化技术 | 775篇 |
出版年
2024年 | 14篇 |
2023年 | 68篇 |
2022年 | 96篇 |
2021年 | 196篇 |
2020年 | 163篇 |
2019年 | 171篇 |
2018年 | 242篇 |
2017年 | 201篇 |
2016年 | 258篇 |
2015年 | 182篇 |
2014年 | 228篇 |
2013年 | 669篇 |
2012年 | 231篇 |
2011年 | 285篇 |
2010年 | 256篇 |
2009年 | 277篇 |
2008年 | 201篇 |
2007年 | 167篇 |
2006年 | 130篇 |
2005年 | 92篇 |
2004年 | 81篇 |
2003年 | 59篇 |
2002年 | 60篇 |
2001年 | 96篇 |
2000年 | 89篇 |
1999年 | 87篇 |
1998年 | 114篇 |
1997年 | 113篇 |
1996年 | 48篇 |
1995年 | 23篇 |
1994年 | 27篇 |
1993年 | 22篇 |
1992年 | 17篇 |
1991年 | 20篇 |
1990年 | 12篇 |
1989年 | 10篇 |
1988年 | 19篇 |
1987年 | 22篇 |
1986年 | 10篇 |
1985年 | 18篇 |
1984年 | 32篇 |
1982年 | 10篇 |
1981年 | 17篇 |
1980年 | 11篇 |
1978年 | 12篇 |
1976年 | 13篇 |
1973年 | 9篇 |
1928年 | 13篇 |
1926年 | 12篇 |
1925年 | 38篇 |
排序方式: 共有5320条查询结果,搜索用时 18 毫秒
1.
Khaled Al-Farhany Mohammed A. Alomari Ahmed Al-Saadi Ali Chamkha Hakan F. Öztop Wael Al-Kouz 《亚洲传热研究》2022,51(2):1691-1710
In the current work, numerical simulations are achieved to study the properties and the characteristics of fluid flow and heat transfer of (Cu–water) nanofluid under the magnetohydrodynamic effects in a horizontal rectangular canal with an open trapezoidal enclosure and an elliptical obstacle. The cavity lower wall is grooved and represents the heat source while the obstacle represents a stationary cold wall. On the other hand, the rest of the walls are considered adiabatic. The governing equations for this investigation are formulated, nondimensionalized, and then solved by Galerkin finite element approach. The numerical findings were examined across a wide range of Richardson number (0.1 ≤ Ri ≤ 10), Reynolds number (1 ≤ Re ≤ 125), Hartmann number (0 ≤ Ha ≤ 100), and volume fraction of nanofluid (0 ≤ φ ≤ 0.05). The current study's findings demonstrate that the flow strength increases inversely as the Reynolds number rises, which pushes the isotherms down to the lower part of the trapezoidal cavity. The Nuavg rises as the Ri rise, the maximum Nuavg = 10.345 at Ri = 10, Re = 50, ϕ = 0.05, and Ha = 0; however, it reduces with increasing Hartmann number. Also, it increase by increasing ϕ, at Ri = 10, the Nuavg increased by 8.44% when the volume fraction of nanofluid increased from (ϕ = 0–0.05). 相似文献
2.
3.
4.
In this study, the effects of changing first wall materials and their thicknesses on a reactor were investigated to determine the displacement per atom(DPA) and gas production(helium and hydrogen) in the first wall, as well as the tritium breeding ratio(TBR) in the coolant and tritium breeding zones. Therefore, the modeling of the magnetic fusion reactor was determined based on the blanket parameters of the International Thermonuclear Experimental Reactor(ITER). Stainless steel(SS 316 LNIG), Oxi... 相似文献
5.
6.
7.
Tekin Ramazan Ertuğrul Ömer Faruk Kaya Yılmaz 《Multimedia Tools and Applications》2020,79(43-44):32541-32561
Multimedia Tools and Applications - In this paper, four novel, simple and robust approaches, which are left to right local binary patterns (LBPLL2R), top to down local binary patterns (LBPT2D),... 相似文献
8.
9.
ABSTRACTWind turbine control is an important task to make the electricity generation secure in terms of energy demand and machine safety. It also yields to control the desired power level and optimized energy because of the assignment of turbine speed. The contactless piezoelectric wind energy harvester (CPWEH) used in this study has three piezoelectric layers located around the shaft with 120 degrees apart and they are buckled by the magnetic force without any physical contact. The superiority of this device is to generate energy for low wind speeds such as 1.5 m/s. However, for high speeds, high total harmonic distortions (THDs) govern the waveforms, thus controlling the turbine speed becomes necessary for optimizing the output power. Encouraged by this, a small low inertia dc generator is coupled with the wind turbine, and the generator terminals are connected to a resistor through a power switch to generate a braking torque that opposes to wind speed direction. By controlling the switch properly, turbine speed is ensured to remain within a certain band, which accordingly prevents the turbine from rotating very fast at damaging wind speeds. Several experiments are performed on the developed CPWEH with/without the presented control scheme which prove the existence of promising performance of our proposal. 相似文献
10.
Scientometrics - A novel hashing algorithm is applied to match two prominent and important bibliographic databases at the paper level. In the literature, such tasks have been studied and conducted... 相似文献