全文获取类型
收费全文 | 396456篇 |
免费 | 4474篇 |
国内免费 | 1786篇 |
专业分类
化学 | 219107篇 |
晶体学 | 6439篇 |
力学 | 16181篇 |
综合类 | 72篇 |
数学 | 42228篇 |
物理学 | 118689篇 |
出版年
2020年 | 3273篇 |
2019年 | 3584篇 |
2018年 | 4440篇 |
2017年 | 4559篇 |
2016年 | 6719篇 |
2015年 | 4358篇 |
2014年 | 6670篇 |
2013年 | 16974篇 |
2012年 | 13328篇 |
2011年 | 16266篇 |
2010年 | 11544篇 |
2009年 | 11408篇 |
2008年 | 14960篇 |
2007年 | 14927篇 |
2006年 | 14009篇 |
2005年 | 12736篇 |
2004年 | 11489篇 |
2003年 | 10350篇 |
2002年 | 10064篇 |
2001年 | 11820篇 |
2000年 | 9019篇 |
1999年 | 6728篇 |
1998年 | 5424篇 |
1997年 | 5351篇 |
1996年 | 5285篇 |
1995年 | 4759篇 |
1994年 | 4757篇 |
1993年 | 4502篇 |
1992年 | 5310篇 |
1991年 | 5274篇 |
1990年 | 5036篇 |
1989年 | 5005篇 |
1988年 | 4943篇 |
1987年 | 4892篇 |
1986年 | 4751篇 |
1985年 | 6216篇 |
1984年 | 6315篇 |
1983年 | 5120篇 |
1982年 | 5405篇 |
1981年 | 5237篇 |
1980年 | 4828篇 |
1979年 | 5324篇 |
1978年 | 5492篇 |
1977年 | 5631篇 |
1976年 | 5476篇 |
1975年 | 5010篇 |
1974年 | 5062篇 |
1973年 | 5087篇 |
1972年 | 3768篇 |
1968年 | 3221篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Franz H. Asthalter T. Dommach M. Ehnes A. Messel K. Sergueev I. 《Hyperfine Interactions》2002,141(1-4):131-134
The present status of the new nuclear resonance beamline PETRA 1 at HASYLAB, DESY, Hamburg is described. Besides an overview
of the experimental setup some examples of recent experiments are given. Those cover the main applications, i.e., inelastic
scattering from iron alloys and quasielastic scattering from glass-forming liquids.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
52.
M. Gorkunov M. Lapine E. Shamonina K.H. Ringhofer 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(3):263-269
Effective magnetic properties of a composite meta-material consisting of periodically arranged circular conductive elements
are studied theoretically. A general expression for the effective bulk permeability is obtained with mutual effects and lattice
ordering being taken into account. The resonance frequency of the permeability is found to be strongly dependent on the size
and shape of the unit cell. Frequency dispersion of the permeability is studied with special attention paid to the frequency
range, where negative values of the permeability are possible. Corresponding recommendations for optimisation of the meta-materials
with negative permeability are made. The results are confirmed by numerical simulations of the finite structure behaviour
in an external magnetic field.
Received 19 April 2002 Published online 31 July 2002 相似文献
53.
An overview of theoretical and experimental studies of the coherent type-B e
+
e-pair production by photons in aligned crystals performed at Nuclear Physics Institute at Tomsk Polytechnic University is given. 相似文献
54.
M. A. Augustyniak-Jabłokow K. Łukaszewicz A. Pietraszko V. E. Petrashen Yu. V. Yablokov 《Physics of the Solid State》2002,44(8):1480-1483
The EPR spectra evolution of Cs2Zn1?x Cux(ZrF6)2 · 6H2O (x=0.01, 0.6, 0.8, and 1.0) in the temperature range 4.2–330 K and the x-ray structure analysis of the compound with x=1.0 in the range 150–327 K show that the Jahn-Teller (JT) complex Cu(H2O)6 coordination sphere undergoes a plastic deformation. The observed effect is due to the combined influence of small lattice strains existing in the paraphase and a new one appearing as a result of a ferroelastic phase transition and increasing with decreasing temperature below T c . It is proved that both cooperative interactions between JT complexes and ferroelastic strain stabilize a certain JT configuration. The problem of instability of a JT configuration compressed at T ~ 265 K is discussed. 相似文献
55.
56.
57.
We analyze diffusion from a periodic array of hemispherical droplets through a membrane. We find that the multiple sources do not interact strongly, even when the droplets are closely spaced, so that the flux through the membrane appears nearly additive. 相似文献
58.
59.
60.
In the present paper, we find a class of linear homogeneous differential equations of order n + 1 (n > 1) whose fundamental system of solutions is constructed from the fundamental system of solutions of a second-order differential
equation. The spectral properties of differential operators generated by these differential expressions are investigated.
In particular, sufficient conditions are obtained for the coefficients of a second-order differential equation under which
the case of maximal deficiency indices is realized.
Dedicated to the memory of B. M. Levitan 相似文献