全文获取类型
收费全文 | 1312篇 |
免费 | 90篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 11篇 |
综合类 | 1篇 |
化学工业 | 326篇 |
金属工艺 | 34篇 |
机械仪表 | 62篇 |
建筑科学 | 44篇 |
矿业工程 | 3篇 |
能源动力 | 139篇 |
轻工业 | 216篇 |
水利工程 | 10篇 |
石油天然气 | 12篇 |
无线电 | 48篇 |
一般工业技术 | 193篇 |
冶金工业 | 40篇 |
原子能技术 | 28篇 |
自动化技术 | 237篇 |
出版年
2024年 | 6篇 |
2023年 | 17篇 |
2022年 | 34篇 |
2021年 | 76篇 |
2020年 | 37篇 |
2019年 | 44篇 |
2018年 | 81篇 |
2017年 | 73篇 |
2016年 | 72篇 |
2015年 | 44篇 |
2014年 | 57篇 |
2013年 | 189篇 |
2012年 | 71篇 |
2011年 | 95篇 |
2010年 | 97篇 |
2009年 | 97篇 |
2008年 | 47篇 |
2007年 | 50篇 |
2006年 | 37篇 |
2005年 | 20篇 |
2004年 | 29篇 |
2003年 | 13篇 |
2002年 | 10篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1996年 | 15篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有1404条查询结果,搜索用时 93 毫秒
1.
2.
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
3.
Serdaroğlu Kemal Çağrı İnanç Barış Baydere Şebnem 《Journal of Network and Systems Management》2022,30(4):1-35
Journal of Network and Systems Management - IoT applications have become a pillar for enhancing the quality of life. However, the increasing amount of data generated by IoT devices places pressure... 相似文献
4.
Al-xNi-yCeO2 (x = 6, 10, 15, 20 and y = 0, 5, 10 wt%) composites were produced by a powder metallurgical production route. Powder mixtures of Al, Ni and CeO2 were fabricated via mechanical alloying (MA) for 4 h in a Spex-type high-energy ball mill. Both the mechanically alloyed (MAed) and non-MAed (as-blended mixtures) powders were pre-compacted in a hydraulic press under 650 MPa and then pressurelessly consolidated at 630 °C for 2 h under an inert atmosphere. The effects of MA process and the amounts of Ni and CeO2 on the microstructural, mechanical and tribological properties of the sintered composites were determined. Based on the SEM and XRD investigations, the MAed powders illustrated a homogenous structure, comprising flaky particles with smaller crystallite sizes and greater lattice strain. According to the XRD analysis, Ni formed Al–Ni intermetallic compounds in the matrix of sintered composites that act as secondary reinforcement phases. The SEM observations conducted on the MAed samples demonstrated more uniformly and finely distributed Al3Ni and CeO2 phases in the microstructure of the MAed samples, unlike the non-MAed ones. The hardness values of sintered composites increased due to the MA process and increasing Ni and CeO2 amounts, and the hardness value of the MAed Al20Ni–10CeO2 sample reached 179 HV. The ultimate compressive strength and failure strain of the MAed Al6Ni–10CeO2 sample were 441 MPa and 11.3%. In the Al20Ni–10CeO2 sample, the compressive strength and failure strain were 391 MPa and 5.5%, respectively. Additionally, the reciprocating wear test results illustrated that both wear resistance and hardness values of the composites increased as the amounts of Ni and CeO2 increased, and the Al20Ni–10CeO2 sample exhibited the highest wear resistance as 0.175 × 10-3 mm3/Nm. 相似文献
5.
Phase change materials (PCM) have an increasingly more important role as a thermal energy storage (TES) media. However, leakage problem of PCM causes limitation during their integration in TES systems. Therefore, the encapsulation of PCMs is attracting research interest to extend usage of PCMs in real TES applications in recent years. In this study, hydroxystearic acid (HSA) was encapsulated with polymethyl methacrylate (PMMA) and different PMMA comonomer shells via emulsion polymerization method for the first time in literature. HSA with high melting temperature range (74–78°C) can widen the scope of using PCMs, and the encapsulated form can make it more versatile. The chemical structures, morphologies, and thermophysical properties of capsules were determined by FT‐IR, SEM, DSC, TGA, and thermal infrared camera. Among the produced HSA capsule candidates, PMMA‐HEMA is the most promising with latent heat of 48.5 J/g with melting range of 47 to 85°C. SEM analysis indicated that the capsules have spherical shape with compact surface at nano‐micro (100–440 nm) size range; however, some capsules exhibited agglomeration. 相似文献
6.
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
7.
Samir Attafi Aklouche-benouaguef Sabiha TALAŞ Şükrü 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(4):786-795
Protection of Metals and Physical Chemistry of Surfaces - The AA6061-T6 alloy is used in many industrial applications such as hydraulic pistons, aerospace and marine vehicle fittings, including the... 相似文献
8.
9.
Betül Sen Sultan Kuzu Enes Demir Tuğba Önal Fatih Şen 《International Journal of Hydrogen Energy》2021,46(24):13510-13514
10.