全文获取类型
收费全文 | 3793篇 |
免费 | 529篇 |
国内免费 | 86篇 |
专业分类
电工技术 | 65篇 |
技术理论 | 2篇 |
综合类 | 485篇 |
化学工业 | 477篇 |
金属工艺 | 314篇 |
机械仪表 | 107篇 |
建筑科学 | 1125篇 |
矿业工程 | 136篇 |
能源动力 | 143篇 |
轻工业 | 22篇 |
水利工程 | 72篇 |
石油天然气 | 6篇 |
武器工业 | 29篇 |
无线电 | 94篇 |
一般工业技术 | 626篇 |
冶金工业 | 310篇 |
原子能技术 | 11篇 |
自动化技术 | 384篇 |
出版年
2025年 | 37篇 |
2024年 | 118篇 |
2023年 | 147篇 |
2022年 | 213篇 |
2021年 | 217篇 |
2020年 | 240篇 |
2019年 | 171篇 |
2018年 | 149篇 |
2017年 | 132篇 |
2016年 | 191篇 |
2015年 | 151篇 |
2014年 | 236篇 |
2013年 | 379篇 |
2012年 | 845篇 |
2011年 | 298篇 |
2010年 | 241篇 |
2009年 | 175篇 |
2008年 | 110篇 |
2007年 | 48篇 |
2006年 | 53篇 |
2005年 | 26篇 |
2004年 | 17篇 |
2003年 | 16篇 |
2002年 | 18篇 |
2001年 | 20篇 |
2000年 | 5篇 |
1999年 | 13篇 |
1998年 | 7篇 |
1997年 | 2篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1990年 | 4篇 |
1988年 | 5篇 |
1987年 | 17篇 |
1986年 | 9篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 8篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1971年 | 4篇 |
1970年 | 6篇 |
1967年 | 5篇 |
1965年 | 18篇 |
1963年 | 2篇 |
1962年 | 2篇 |
排序方式: 共有4408条查询结果,搜索用时 15 毫秒
1.
《Composites Science and Technology》2007,67(3-4):525-529
Carbon/carbon composites containing zirconium were prepared using chopped carbon fiber, mesophase pitch and Zr powder by the traditional process including molding, carbonization, densification and graphitization. The influence of Zr on the microstructure and properties of the composites were investigated. Results show that Zr can improve the interface bonding, promote more perfect and larger crystallites and enhance the conductive/mechanical properties of the composites. The high in-plane thermal conductivity of 464 W/(m K) and excellent bending strength of 83.6 MPa was obtained for a Zr content of 13.9 wt% at heat treatment temperature(HTT) of 2500 °C. However the conductive/mechanical properties of the composites decrease dramatically for an higher HTT of 3000 °C. SEM micrograph of the fracture surface for the composites shows that lower disorder crystallite arrangement of fiber and carbon matrix come into being in the composites during HTT of 3000 °C, which should be responsible for the low properties. Correlation between the content of Zr and the microstructure and properties are discussed. 相似文献
2.
陈明淑 《数字社区&智能家居》2013,(13):3159-3163,3179
该文结合循环流化床锅炉的特点,采用了霍尼韦尔公司的EPKS控制系统对锅炉进行控制,设计了硬件的配置,主要设计了控制策略,将模糊解耦控制应用在控制策略中,进行了实验仿真,实验结果表明模糊解耦控制具有良好的解耦效果。 相似文献
3.
P. Bailly F. Delvare J. Vial J.L. Hanus M. Biessy D. Picart 《International Journal of Impact Engineering》2011,38(2-3):73-84
Low velocity impacts on energetic materials induce plastic deformations and sliding friction which can lead to ignition. If some ignition criteria have been proposed, the remaining difficulty is to characterize the mechanical behavior of the material when submitted to the corresponding solicitations (high pressure and high strain rate). Thus, a technique based on the Split Hopkinson Pressure Bars system is proposed to carry out a triaxial compression test. A cylindrical specimen is placed into a confining ring and is compressed by the system of bars. The ring prevents the radial extension of the specimen and creates a lateral confining pressure. The material and dimensions chosen for the ring maintain a constant radial pressure during the test. Some tests were carried out on an inert aggregate material and proved the validity of this experimental device. The experimental data processing shows the influence of both the pressure and the strain rate. The shear stresses, which contribute to thermal dissipation and then to the ignition threshold, increase according to the pressure. 相似文献
4.
5.
《International Journal of Heat and Mass Transfer》2006,49(19-20):3325-3337
This work is devoted to both experimental and numerical investigations of the hydrodynamics and associated heat transfer in two-dimensional microchannels from 700 μm to 200 μm in height. The design of the test section enabled to vary the channel height and to set a quasi-constant heat flux at the microchannel surface. Laminar developing, transitional and turbulent regimes of water flows were explored (200 < Re < 8000). A significant decrease in the Nusselt number was observed in the laminar regime when the channel spacing was decreased while the Poiseuille number remained unchanged in regard to conventional channel flow. It is shown that a bias effect in the solid/fluid interface temperature measurements is most likely responsible for this scale effect. The temperature error was estimated and accounted for in the determination of the Nusselt number. The corrected values have been found to be consistent with the conventional laws both in the laminar and in the beginning of the turbulent regime. 相似文献
6.
Yong Li Juan Wang HuiXing Huang Jia Wang Mi Zhang MMeng Liang 《Advanced Powder Technology》2019,30(8):1442-1449
The electronic conductivity enhanced has been extensively studied and reported in lithium iron phosph-ate (LiFePO4). However, only few existing literatures are available for researchers to enhance simultaneously the ion and electronic conductivity of LiFePO4. Herein, we disclose that the LiFePO4 is co-coated with novel GdPO4 and Carbon via a hydrothermal-assisted solid-phase method, contributing to particle size and dispersibility. What surprising is that the ionic and electronic conductivity of the material is significantly enhanced, and the interfacial side reaction is effectively inhibited between the materials and the electrolytes. The diverse proportions of the mixed coating (LiFePO4/C&xGdPO4 (x = 0, 1 wt%, 2 wt%, 3 wt%, 4 wt%)) are synthesized compared with bare LiFePO4. The experimental results suggest that LiFePO4/C&0.03GdPO4 exhibits the most excellent electrochemical performance. There is discharge capacity of 158, 148.8, 141.6, 134.9, 121.8, 104.9, and 86.7mAh/g at 0.1, 0.2, 0.5, 1, 2, 5, and 10 C rates, respectively. 相似文献
7.
8.
9.
10.