全文获取类型
收费全文 | 53篇 |
免费 | 43篇 |
国内免费 | 21篇 |
专业分类
化学 | 17篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 8篇 |
物理学 | 88篇 |
出版年
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 1篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 1篇 |
2012年 | 4篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 12篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2003年 | 9篇 |
2002年 | 9篇 |
2001年 | 2篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1990年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有117条查询结果,搜索用时 15 毫秒
51.
52.
颉科让 《纯粹数学与应用数学》1990,6(2):26-32
本文给出了均值为θ,协方差矩阵为∑(∑正定未知)的P(P≥3)维正态总体均值θ在损失L(δ(x),θ)=((x)-θ)’∑~(-1)((x)-θ)之下的一类广义的Bayes minimax估计,推广了Berger[2]的结果。 相似文献
53.
Electron Impact Excitations and Linear Polarization for 1s2 1S0-1s2p3,1P1 Lines of Fe24+ Ions under Screened Coulomb Interactions
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)
Electron impact excitation cross sections from the ground state to the individual magnetic sublevels of 1s2p 3'1P1 states in high-temperature dense plasmas are calculated for highly charged He-like Fe24+ ions by using a fully relativistic distorted-wave method. The Debye-Huckel screening model is used to screen the projectile electron from the nucleus and target electrons. The linear polarization degrees for these lines are obtained. It is found that the cross sections at all incident energies decrease with the increase of the screening for these excitations. The influence of screening on linear polarization degrees of the 1P1 line is very small. The linear polarization degrees of aP1 line decrease sharply at low incident energy with the increase of the screening. 相似文献
54.
利用基于多组态Dirac-Fock理论方法的原子结构及性质计算程序GRASP92,详细研究了类氟W65+到类锂W71+离子的2p38/2—2s1/2跃迁性质.计算结果与Podpaly等[Phys.Rev.A 80 052504(2009)]的实验结果符合得非常好.在此基础上,利用全相对论扭曲波方法研究了2s1/2—2p1/2的电子碰撞激发总截面和磁子能级碰撞激发截面以及部分谱线的线性极化度,分析了电子碰撞激发截面和谱线线性极化度随碰撞能量的变化规律. 相似文献
55.
描述了利用实验物理与工业控制系统(EPICS)平台对HL-2A主机运行参数进行的集中测控系统开发。系统采用s7nodave设备驱动模块,实现了Soft IOC与各PLC的通讯,将各子系统的PLC集成到了EPICS控制系统中。通过对关系型数据库和应用层软件CSS中数据归档及报警等组件的扩展与配置,实现OPI层与各个子系统的实时通信。测控系统成功地将HL-2A主机参数集中在EPICS平台下运行,为下一代装置的主机集中测控系统设计打下了基础。 相似文献
56.
As part of the international research program on the superconducting cavity for the International Linear Collider (ILC) R&;D on the 1.3 GHz low loss superconducting cavities has been carried out at the Institute of High Energy Physics (IHEP) since 2005. A design of 1.3 GHz low loss cavity shape was proposed and six single-cell cavities of different niobium material were successfully fabricated with standard technology. In this study our priority was on large grain (LG) cavities. The two LG cavities were treated with complete procedures of surface treatments based on chemical polishing (CP) without electro polishing (EP) at IHEP. The two LG cavities and a fine grain cavity were sent to KEK for vertical testing. All the three cavities reached accelerating gradients higher than 35 MV/m and the maximum gradient of 40.27 MV/m was achieved in the LG cavity. This paper presents the process of the vertical RF tests and the comparison of the LG and fine grain cavities's performance. 相似文献
57.
马铃薯重离子辐射育种研究 总被引:3,自引:0,他引:3
在2000—2005年将杂交技术和重离子辐射相结合, 采用55 MeV/u的 40Ar17+离子对马铃薯杂交种子和微型薯进行了不同剂量的贯穿辐射或离子注入处理。 结果表明, 对马铃薯微型薯进行重离子辐射能显著提高块茎的产量。 而杂交技术和重离子辐射相结合是一种更高效的育种方式, 不仅能提高块茎的增产幅度, 还能改善其加工品质。 微型薯重离子辐射的最佳剂量为60 Gy, 杂交种子辐射的适宜剂量范围在60—120 Gy之间。 通过对辐射后代的多年选育, 获得了几个产量显著高于对照、 品质优良的马铃薯新品系。 The effect of 55 MeV/u 40Ar17+ irradiation with different doses on hybrid seeds and micro tubers of potatoes were studied from year 2000 to 2005. The results showed that the yields of potatoes irradiated by heavy ions grew significantly. This new mutation method combining cross breeding technique with heavy ion irradiation is more effective, which could not only increase the yield of potatoes, but also improve their quality. The optimal mutagenic dose was 60 Gy to micro tubers of potatoes, 60—120 Gy to hybrid seeds, respectively. Finally, several new lines which have higher yield and better qualities were obtained through multi generation screening from the offspring of irradiated potatoes. 相似文献
58.
59.
This paper calculates the transition wavelengths and probabilities
of the two-electron and one-photon (TEOP) transition from the
$(3{\rm s}^{-1}_{1/2}4{\rm d}_{j})_{J=1,2}$ to $(3{\rm
p}^{-1}_{3/2}4{\rm s}_{1/2})_{J=1}$ and the $(3{\rm
p}^{-1}_{1/2}4{\rm s}_{1/2})_{J=1}$ to $(3{\rm d}^{-1}_{j}4{\rm
d}_{j'})_{J=1,2}$ for highly charged Ni-like ions with atomic number
$Z$ in the range $47\leq Z\leq92$. In the calculations, the
multi-configuration Dirac--Fock method and corresponding program
packages GRASP92 and REOS99 were used, and the relativistic effects,
correlation effects and relaxation effects were considered
systematically. It is found that the TEOP transitions are very
sensitive to the correlation of electrons, and the probabilities
will be enhanced sharply in some special $Z$ regions along the
isoelectronic sequence. The present TEOP transition wavelengths are
compared with the available data from some previous publications,
good agreement is obtained. 相似文献
60.
本文给出了一些用一族具有Riesz分解性质的效应代数黏合成齐次的效应代数的条件,并研究了通过线性MV-代数替换正交代数中的原子得到只含有1型原子的有限的齐次效应代数的方法。 相似文献