首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   321篇
  免费   116篇
  国内免费   22篇
化学   50篇
晶体学   3篇
力学   34篇
综合类   2篇
数学   29篇
物理学   341篇
  2023年   5篇
  2022年   11篇
  2021年   6篇
  2020年   7篇
  2019年   8篇
  2018年   7篇
  2017年   15篇
  2016年   14篇
  2015年   18篇
  2014年   18篇
  2013年   22篇
  2012年   17篇
  2011年   18篇
  2010年   16篇
  2009年   18篇
  2008年   19篇
  2007年   17篇
  2006年   19篇
  2005年   24篇
  2004年   16篇
  2003年   17篇
  2002年   17篇
  2001年   9篇
  2000年   18篇
  1999年   13篇
  1998年   7篇
  1997年   6篇
  1996年   8篇
  1995年   6篇
  1994年   5篇
  1993年   11篇
  1992年   7篇
  1991年   6篇
  1990年   6篇
  1989年   2篇
  1988年   3篇
  1987年   5篇
  1986年   2篇
  1984年   3篇
  1982年   3篇
  1979年   1篇
  1977年   3篇
  1976年   4篇
  1975年   2篇
排序方式: 共有459条查询结果,搜索用时 218 毫秒
1.
刘江涛  周云松  王福合  顾本源 《物理学报》2004,53(10):3336-3340
讨论了利用由反常色散材料构成的二维(2D)光子晶体(PCs)实现超窄带滤波(PCADOF)的原理,并对铯原子蒸气6P3/2←6S1/2谱线的反常色散曲线进行了研究,讨论利用此反常色散曲线通过2D PCs实现超窄带滤波的方法和特点,研究发现这种滤光器的带宽可达到0.002nm,这将为设计一种全新的滤波器提供指导. 关键词: 反常色散 光子晶体 超窄带滤波  相似文献   
2.
Advances in gauge theories and unified theories have not thrown light on the meaning of electron. The problem of the origin of electronic charge is made precise, new insights gained from Weyl space are summarized, and the origin of charge in terms of fractional spin is suggested. A new perspective on the abelian Chern-Simons theory is presented to explain charge.  相似文献   
3.
刘璐  王江波  俞水清  汤俊雄 《光学学报》2004,24(12):590-1594
提出级联佛克脱型原子滤光器(Linked VADOF)的新构想。从理论上分析并计算了级联佛克脱型原子滤光器的透射谱。结果表明,级联佛克脱型原子滤光器将佛克脱型原子滤光器的多峰改造为单峰结构,具有比佛克脱型原子滤光器更窄的线宽和更高的噪声抑制比。将这种新型结构应用于激光信标锁频。该锁频方案提高了信标光频率的稳定性。在此基础上,给出了发射端采用级联佛克脱型原子滤光器锁频,接收端采用法拉第型原子滤光器(FADOF)滤光的新型卫星激光链路系统。外场初步联调实验表明了该系统的可行性。  相似文献   
4.
Extensive Monte Carlo simulations of theant-in-the-labyrinth problem on randomL* L* L simple cubic lattices are performed, forL up to 960 on a CRAY-YMP supercomputer. The exponentk for the rms displacementr witht inrt k is found to bek=0.190±0.003. As a second approach, large percolation clusters with chemical shells up to 300 are generated on a simple cubic lattice at criticality. The diffusion equation is then solved by using the exact enumeration technique. The corresponding critical exponentd w is found to be 1/d w =0.250±0.003.On leave from I. Institut für Theoretische für Physik, Universität Hamburg, D-2000 Hamburg, Federal Republic of Germany.  相似文献   
5.
We present some asymptotic results for the family of pausing time densities having the asymptotic (t) property(t) [t ln1+(t/T)]–1. In particular, we show that for this class of pausing time densities the mean-squared displacement r 2(t) is asymptotically proportional to ln(t/T), and the asymptotic distribution of the displacement has a negative exponential form.  相似文献   
6.
The distribution characteristics of Er3+ ions doped in the oxyfluoride glass ceramics containing LaF3 nanocrystals heat-treated at 650 ℃ for different durations were investigated. The results of the integral absorption cross-section analysis demonstrated that the partition fraction of Er3+ in LaF3 nanocrystals increases with prolonging of heating time. The anomalous phenomena of Er3+ emissions in the up-and the down-conversion fluorescence spectra are well explained based on the calculated results.  相似文献   
7.
A review is given on the main problems associated with the determination and interpretation of molecular diffusion in zeolites. It is shown that the diffusivities may most decisively depend on the relevant space and time scales of observation, as well as on the physical state under which the measurements are carried out. Special emphasis is given to the microscopic techniques and their most recent evidence on the existence of transport resistances distributed over the intracrystalline space.  相似文献   
8.
Yu. D. Fomin 《Molecular physics》2019,117(20):2786-2792
ABSTRACT

Heat capacity of several liquids which demonstrate anomalous behaviour is studied. It is shown that isochoric heat capacity of these liquids shows anomalously high values which is related to smooth structural crossover in these liquids. This phenomenon can be used for qualitative explanation of high heat capacity of water and some other substances.  相似文献   
9.
After a brief review of the muon g-2 status,we discuss hypothetical errors in the Standard Model prediction that might explain the present discrepancy with the experimental value.None of them seems likely.In particular,a hypothetical increase of the hadroproduction cross section in low-energy e+e-collisions could bridge the muon g-2 discrepancy,but it is shown to be unlikely in view of current experimental error estimates.If,nonetheless,this turns out to be the explanation of the discrepancy,then the 95% CL upper bound on the Higgs boson mass is reduced to about 135 GeV which,in conjunction with the experimental 114.4 GeV 95%CL lower bound,leaves a narrow window for the mass of this fundamental particle.  相似文献   
10.
朱嘉鹏  马丽  周仕明  苗君  姜勇 《中国物理 B》2015,24(1):17101-017101
Tbx(Ni0.8Fe0.2)1-x films with x≤0.14 are fabricated and the anomalous Hall effect is studied.The intrinsic anomalous Hall conductivity and the extrinsic one from the impurity and phonon induced scattering both increase with increasing x.The enhancement of the intrinsic anomalous Hall conductivity is ascribed to both the weak spin–orbit coupling enhancement and the Fermi level shift.The enhancement of the extrinsic term comes from the changes of both Fermi level and impurity distribution.In contrast,the in-plane and the out-of-plane uniaxial anisotropies in the Tb Ni Fe films change little with x.The enhancement of the Hall angle by Tb doping is helpful for practical applications of the Hall devices.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号