全文获取类型
收费全文 | 931篇 |
免费 | 130篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 28篇 |
综合类 | 10篇 |
化学工业 | 73篇 |
金属工艺 | 24篇 |
机械仪表 | 26篇 |
建筑科学 | 31篇 |
矿业工程 | 14篇 |
能源动力 | 28篇 |
轻工业 | 25篇 |
水利工程 | 78篇 |
石油天然气 | 6篇 |
无线电 | 157篇 |
一般工业技术 | 169篇 |
冶金工业 | 255篇 |
原子能技术 | 4篇 |
自动化技术 | 138篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 18篇 |
2020年 | 28篇 |
2019年 | 26篇 |
2018年 | 46篇 |
2017年 | 16篇 |
2016年 | 31篇 |
2015年 | 26篇 |
2014年 | 25篇 |
2013年 | 29篇 |
2012年 | 29篇 |
2011年 | 36篇 |
2010年 | 33篇 |
2009年 | 24篇 |
2008年 | 27篇 |
2007年 | 29篇 |
2006年 | 26篇 |
2005年 | 51篇 |
2004年 | 32篇 |
2003年 | 36篇 |
2002年 | 56篇 |
2001年 | 33篇 |
2000年 | 19篇 |
1999年 | 23篇 |
1998年 | 89篇 |
1997年 | 56篇 |
1996年 | 45篇 |
1995年 | 25篇 |
1994年 | 21篇 |
1993年 | 16篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 13篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1981年 | 3篇 |
1977年 | 3篇 |
1976年 | 16篇 |
1968年 | 4篇 |
1963年 | 1篇 |
1959年 | 3篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有1066条查询结果,搜索用时 7 毫秒
1.
2.
斜拉桥索导管的施工监控 总被引:1,自引:0,他引:1
斜拉索是斜拉桥的重要组成部分。是弹性连续主梁的弹性支座。其到位精度直接影响主梁的受力。所以它的施工监控就十分重要。结合仙桃汉江公路大桥索导管的施工监控过程,对索导管的场内加工、安装就位、成品验收等一系列监控流程作了详细介绍,并提出一些积极建议,以期对斜拉桥的施工起到推进作用。 相似文献
3.
M. Mahesh Y. S. Wong J. Y. H. Fuh H. T. Loh 《The International Journal of Advanced Manufacturing Technology》2006,31(3-4):374-387
This paper presents a methodology of using six-sigma quality tools for benchmarking of rapid prototyping & manufacturing (RP&M) processes. It involves the fabrication of a geometric benchmark part and a methodology to control and identify the best performance of the process to reduce the variablity in the fabricated parts. The approach is demonstrated with a case study based on the direct laser sintering (DLS) process for prototyping using plastic powder. In the case study an identified set of six-sigma/ statistical process control tools is employed to determine and best tune factors affecting the desired outcomes of the built parts. 相似文献
4.
Editable Supercapacitors with Customizable Stretchability Based on Mechanically Strengthened Ultralong MnO2 Nanowire Composite 下载免费PDF全文
Zhisheng Lv Yifei Luo Yuxin Tang Jiaqi Wei Zhiqiang Zhu Xinran Zhou Wenlong Li Yi Zeng Wei Zhang Yanyan Zhang Dianpeng Qi Shaowu Pan Xian Jun Loh Xiaodong Chen 《Advanced materials (Deerfield Beach, Fla.)》2018,30(2)
Although some progress has been made on stretchable supercapacitors, traditional stretchable supercapacitors fabricated by predesigning structured electrodes for device assembling still lack the device‐level editability and programmability. To adapt to wearable electronics with arbitrary configurations, it is highly desirable to develop editable supercapacitors that can be directly transferred into desirable shapes and stretchability. In this work, editable supercapacitors for customizable shapes and stretchability using electrodes based on mechanically strengthened ultralong MnO2 nanowire composites are developed. A supercapacitor edited with honeycomb‐like structure shows a specific capacitance of 227.2 mF cm?2 and can be stretched up to 500% without degradation of electrochemical performance, which is superior to most of the state‐of‐the‐art stretchable supercapacitors. In addition, it maintains nearly 98% of the initial capacitance after 10 000 stretch‐and‐release cycles under 400% tensile strain. As a representative of concept for system integration, the editable supercapacitors are integrated with a strain sensor, and the system exhibits a stable sensing performance even under arm swing. Being highly stretchable, easily programmable, as well as connectable in series and parallel, an editable supercapacitor with customizable stretchability is promising to produce stylish energy storage devices to power various portable, stretchable, and wearable devices. 相似文献
5.
The authors demonstrate pure self-starting mode-locked operation in a fiber Fabry-Perot cavity. The laser produces 1.6 ps transform-limited soliton pulses by means of nonlinear polarization evolution in conjunction with an intracavity fiber polarizer. This laser system can be used for the generation and study of soliton pulses in the picosecond regime. With a careful choice of the fiber dispersion and fiber length, the system should also be able to operate in the femtosecond regime. The advantage of the system over existing self-starting fiber soliton lasers is that an optical isolator (an expensive component) is not required. The replacement of the two mirrors with fiber reflection gratings would make this configuration a truly all-fiber device 相似文献
6.
Poh Chiang Loh Vilathgamuwa D.M. Gajanayake C.J. Yih Rong Lim Chern Wern Teo 《Power Electronics, IEEE Transactions on》2007,22(2):498-507
The newly proposed Z-Source inverter has been proven in the literature to exhibit both steady-state voltage buck and boost capabilities using a unique LC impedance network coupled between the power source and converter circuit. This paper now presents transient modeling and analysis of a voltage-type Z-source inverter. These aspects are found to be challenging and they need to be carefully investigated before attempting to design advanced control algorithms for controlling the Z-source inverter. Through detailed analysis, the paper identifies several phenomena on the dc and ac-sides of the inverter, which would result in the inverter having a non-minimum-phase transient response. The dc-side phenomenon is associated with the Z-source impedance network, which is shown through small-signal and signal-flow-graph analyses to be having a right-half-plane zero in its control-to-output transfer function. Also, the ac-side phenomenon is shown through space vector analysis to depend on the time intervals of inverter states used for reconstructing the desired inverter output voltage. Based on the ac vectorial analysis, a method for improving the inverter transient response is also presented. Last, simulation results obtained using a switching-functional model and experimental results obtained using a laboratory prototype are presented for validating the described theoretical concepts 相似文献
7.
8.
9.
10.