全文获取类型
收费全文 | 815篇 |
免费 | 55篇 |
国内免费 | 22篇 |
专业分类
电工技术 | 260篇 |
综合类 | 32篇 |
化学工业 | 48篇 |
金属工艺 | 13篇 |
机械仪表 | 93篇 |
建筑科学 | 8篇 |
矿业工程 | 11篇 |
能源动力 | 59篇 |
轻工业 | 4篇 |
水利工程 | 15篇 |
石油天然气 | 4篇 |
武器工业 | 4篇 |
无线电 | 124篇 |
一般工业技术 | 15篇 |
冶金工业 | 10篇 |
原子能技术 | 29篇 |
自动化技术 | 163篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 13篇 |
2020年 | 18篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 22篇 |
2016年 | 14篇 |
2015年 | 23篇 |
2014年 | 42篇 |
2013年 | 35篇 |
2012年 | 52篇 |
2011年 | 65篇 |
2010年 | 60篇 |
2009年 | 40篇 |
2008年 | 42篇 |
2007年 | 35篇 |
2006年 | 51篇 |
2005年 | 45篇 |
2004年 | 53篇 |
2003年 | 50篇 |
2002年 | 32篇 |
2001年 | 31篇 |
2000年 | 16篇 |
1999年 | 24篇 |
1998年 | 33篇 |
1997年 | 15篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有892条查询结果,搜索用时 170 毫秒
31.
本文结合我国大型汽轮发电机组轴系扭振在线监测分析系统(简称TSA)的开发研制,概括介绍了目前国内外比较关注的大型汽发机组轴系扭振与监测问题。TSA系统的应用对于机组的扭振事件分析、经济运行与安全保证是非常重要的。 相似文献
32.
针对数字接收机中如何全数字地实现位同步,设计了一种内插位同步法。利用内插与Gardner算法相结合的原理设计位同步,通过System Generator进行建模仿真,并直接生成代码下载到FPGA实现位同步。利用QPSK信号进行仿真分析,FPGA硬件协同仿真进行验证。实验结果表明,内插位同步法具有很好的位同步效果。 相似文献
33.
Dielectric barrier discharge (DBD) reactors used as ozone generators are well known today and widely used for water treatment and air disinfection. The purpose of this article is to propose an experimental procedure based on the response surface modeling in order to optimize the geometrical dimensions of the cylindrical shape ozone generator, i.e., the discharge gap and the electrodes length. Because an effective ozone generator is expected to give high ozone concentration with a minimum of power requirements, the applied high voltage was associated with the geometrical parameters to carry out a composite centered faces design. Obtained results indicate that for an efficient ozone generator, length of the electrodes needs to be optimized while the discharge gap should be minimized. 相似文献
34.
Surface oxidation using ozone gas, produced by an electrolytic ozone generator, was applied for preparation of a gas-diffusion electrode (GDE) for an electrochemical energy conversion system. An uncatalyzed carbon sheet containing poly(tetrafluoroethylene) binder was first placed into contact with ozone gas to form active functional groups on the surface of the carbon; then ion-exchange between a weakly bound hydrogen of the functional groups and a platinum cation complex was performed. A GDE having highly dispersed particles of a platinum metal deposited on a porous carbon sheet ws developed by this method. The fuel cell using this GDE showed high performance. 相似文献
35.
36.
The slight-alkalization of generator internal cooling water (GICW) is widely used to inhibit the corrosion of hollow copper conductor and thereby ensure the safe operation of the generator. CO2 inleakage is increasingly identified as a potential security risk for GICW system. In this paper, the influence of CO2 inleakage on the slight-alkalization of GICW was theoretically discussed. Based on the equilibriums of the CO2-NaOH-H2O system, CO2 inleakage saturation was derived to quantify the amount of the dissolved CO2 in GICW. This parameter can be directly calculated with the measured conductivity and the [Na+] of GICW. The influence of CO2 inleakage on the slight-alkalization conditioning of GICW and the measurement of its water quality parameters were then analyzed. The more severe the inleakage, the narrower the water quality operation ranges of GICW, resulting in the more difficult the slight-alkalization conditioning of GICW. The temperature calibrations of the conductivity and the pH value of GICW show non-linear correlations with the amount of CO2 inleakage and the NaOH dosage. This study provides insights into the influence of CO2 inleakage on the slight-alkalization of GICW, which can serve as the theoretical basis for the actual slight-alkalization when CO2 inleakage occurs. 相似文献
37.
This paper presents a self-optimizing robust control scheme that can maximize the power generation for a variable speed wind turbine with Doubly-Fed Induction Generator (DFIG) operated in Region 2. A dual-loop control structure is proposed to synergize the conversion from aerodynamic power to rotor power and the conversion from rotor power to the electrical power. The outer loop is an Extremum Seeking Control (ESC) based generator torque regulation via the electric power feedback. The ESC can search for the optimal generator torque constant to maximize the rotor power without wind measurement or accurate knowledge of power map. The inner loop is a vector-control based scheme that can both regulate the generator torque requested by the ESC and also maximize the conversion from the rotor power to grid power. An ℋ∞ controller is synthesized for maximizing, with performance specifications defined based upon the spectrum of the rotor power obtained by the ESC. Also, the controller is designed to be robust against the variations of some generator parameters. The proposed control strategy is validated via simulation study based on the synergy of several software packages including the TurbSim and FAST developed by NREL, Simulink and SimPowerSystems. 相似文献
38.
张元争 《中国水能及电气化》2007,(7):51-55
对农村小水电站高低压机组抢修中的干燥方法和技术作了较全面的分析和归纳,尤其对高等级绝缘发电机的干燥技术作了较详细的说明,可作为农村新建、老电站灾后(或受潮后)机组抢修时参考。 相似文献
39.
40.