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   307篇
  免费   21篇
  国内免费   2篇
化学   171篇
力学   1篇
综合类   3篇
数学   21篇
物理学   134篇
  2021年   3篇
  2020年   4篇
  2019年   7篇
  2017年   2篇
  2016年   4篇
  2015年   10篇
  2014年   8篇
  2013年   7篇
  2012年   11篇
  2011年   11篇
  2010年   3篇
  2009年   4篇
  2008年   7篇
  2007年   12篇
  2006年   11篇
  2005年   6篇
  2004年   9篇
  2003年   14篇
  2002年   15篇
  2001年   14篇
  2000年   10篇
  1999年   6篇
  1998年   3篇
  1997年   3篇
  1996年   12篇
  1995年   9篇
  1994年   4篇
  1993年   4篇
  1992年   3篇
  1991年   4篇
  1990年   3篇
  1989年   2篇
  1988年   7篇
  1986年   2篇
  1985年   7篇
  1983年   9篇
  1982年   3篇
  1981年   6篇
  1979年   11篇
  1978年   6篇
  1977年   4篇
  1976年   7篇
  1975年   2篇
  1974年   2篇
  1973年   7篇
  1971年   2篇
  1968年   9篇
  1933年   2篇
  1928年   2篇
  1901年   1篇
排序方式: 共有330条查询结果,搜索用时 15 毫秒
91.
92.
93.
Zeitschrift für Physik A Hadrons and nuclei - The nuclear electric quadrupole moment of41Ca, which contains a single neutron outside closed proton and neutron shells (N=Z=20) has been...  相似文献   
94.
The microwave spectrum of the molecular transient disulfur monoxide, S2O, has been reexamined and the microwave measurements have been extended into the millimeterwave region. From the present data, the following ground-state rotational constants and quartic distortion constants have been obtained (MHz):
A = 41915.44, B = 5059.07, C = 4507.19
δJ = 1.895 X 10?, δJK = ?3.192 X 10?2,δK = 1.197 X 100
δJ = 3.453 X 10?4 and δK = 1.223 X 10?2
The centrifugal distortion constants obtained from the rotational spectrum are used to discuss the vibrational spectrum of disulfur monoxide.  相似文献   
95.
The hyperfine structure of the 62 P 1/2 and 72 P 1/2 state of85Rb and87Rb and of the 62 P 3/2 state of87Rb has been investigated with optical double resonance at intermediate magnetic fields. The magnetic interaction constants,g j factors and lifetimes are: $$\begin{gathered} 6^2 P_{1/2} state: A\left( {^{85} Rb} \right) = 39.11\left( 3 \right) MHz,A\left( {^{87} Rb} \right) = 132.56 \left( 3 \right)MHz, \hfill \\ g_j = 0.6659\left( 3 \right), \tau = 1.14\left( {13} \right) \cdot 10^{ - 7} \sec , \hfill \\ 7^2 P_{1/2} state: A\left( {^{85} Rb} \right) = 17.68\left( 8 \right)MHz,A\left( {^{87} Rb} \right) = 59.92\left( 9 \right)MHz, \hfill \\ g_j = 0.6655\left( 5 \right), \hfill \\ 6^2 P_{3/2} state: g_j = 1.3337\left( {10} \right), \tau = 1.12\left( 8 \right) \cdot 10^{ - 7} \sec for ^{87} Rb. \hfill \\ \end{gathered} $$ From the hfs coupling constants of then 2 P multiplets a 11.5% core polarization contribution to the magnetic hfs of then 2 P 3/2 states is obtained, which is found to be independent from the main quantum numbern. The expectation values <r ?3> j for thenp valence electrons corrected for core polarization are compared with those derived from the2 P fine structure separation. Good agreement is achieved for allnp levels with the choice ofZ i =Z?3=34 for the effective nuclear charge number. The nuclear quadrupole moments of85Rb and87Rb are rederived on the basis of this more improved treatment for thep-electron-nucleus interaction yielding $$\begin{gathered} Q_N \left( {^{85} Rb} \right) = + 0.274\left( 2 \right) \cdot 10^{ - 24} cm^2 \hfill \\ Q_N \left( {^{85} Rb} \right) = + 0.132\left( 1 \right) \cdot 10^{ - 24} cm^2 \hfill \\ \end{gathered} $$ where the error does not include the remaining theoretical uncertainty of about 10%.  相似文献   
96.
An optical pumping experiment was performed to obtain precise hfs shifts for Cs in Argon. The shifts measured include a term quadratic in the densityρ and a large temperature coefficient. The coefficients of the expansionδv/v 0=a ρ+bρ 2 area(80 °C)=?29.8(6)x10?9(Torr?1(0°C))b(80 °C)=+11(2)x10?14(Torr?2(0 °C)). The shift grows more negative with increasing temperature by 0.37 (2)%/°C.  相似文献   
97.
98.
Microwave measurements of rotational transitions within vibrationally excited states of several isotopic species of HCN have given improved values for the pertinent Bv constants. These new data have been combined with infrared measurements given in the literature (ncluding Dv terms) to arrive at a set of rovibrational constants (α and γ constants) which is consistent with all available data. Bond distances resulting from several different Be approximations are intercompared to assess the variability of the re values and the importance of the γ terms. The latest r0 and rs bond distances are also given.  相似文献   
99.
100.
A laser spectrometer with an intracavity atomic beam having a spectral resolution of about 3 MHz was developed and applied to atomic resonance fluorescence spectroscopy of the very weak Ca intercombination line λ=6573 Å.  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