全文获取类型
收费全文 | 195篇 |
免费 | 41篇 |
国内免费 | 38篇 |
专业分类
化学 | 55篇 |
晶体学 | 2篇 |
力学 | 2篇 |
综合类 | 2篇 |
数学 | 2篇 |
物理学 | 97篇 |
综合类 | 114篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 12篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 7篇 |
2013年 | 10篇 |
2012年 | 22篇 |
2011年 | 21篇 |
2010年 | 12篇 |
2009年 | 16篇 |
2008年 | 10篇 |
2007年 | 13篇 |
2006年 | 14篇 |
2005年 | 9篇 |
2004年 | 14篇 |
2003年 | 14篇 |
2002年 | 9篇 |
2001年 | 15篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有274条查询结果,搜索用时 687 毫秒
271.
Two couples of low pressure multi-wire proportional chambers (MWPC) were located in the target chamber to detect fission fragments in a hypernuclei producing experiment at Thomas Jefferson National Laboratory (Jlab). In the experiment, a continuous wave (CW) electron beam was applied to form hypernuclei by electromagnetic interaction. In the target chamber, the high energy (1.853 GeV) and high intensity (500 nA) primary electron beam caused a high particle background, which influenced the detection of the fission fragments. This report described the design of the MWPCs and studied the fission-fragment detecting performance of them under such a high background. The efficiency of the MWPCs was given with the help of a high resolution kaon spectrometer. At the same time, the background particles were discussed with a Monte Carlo code based on GEANT4. 相似文献
272.
273.
Generalized Principal-State-of-Polarization Analysis and Matrix Model for Piezoelectric Polarization Controllers
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We introduce a generalized concept of principal state of polarization (PSP) to analyse the piezoelectric polarization controller (PPC) and find each PPC unit can be described by a rotation matrix determined by the PSP. Our PPC has three components, each made of a jaw and a piezoelectric actuator with the squeezing direction tilted 0°, 45° and 0°, which are driven by a tunable power supply. We demonstrate that all the polarization rotation angles are linear to driving voltages and the PSP of unit 2 is nearly orthogonal to others which are almost equal. Taking some approximate treatments we obtain the matrix model of our PPC with respect to three driving voltages. The average error of our theoretical model is 1.51°, and the polarization response time is 〈50 μs, which is promising to realize an open-loop control of polarization. 相似文献
274.