全文获取类型
收费全文 | 1439篇 |
免费 | 21篇 |
国内免费 | 7篇 |
专业分类
化学 | 754篇 |
晶体学 | 13篇 |
力学 | 49篇 |
数学 | 291篇 |
物理学 | 360篇 |
出版年
2021年 | 14篇 |
2020年 | 13篇 |
2019年 | 11篇 |
2017年 | 12篇 |
2016年 | 28篇 |
2015年 | 20篇 |
2014年 | 18篇 |
2013年 | 70篇 |
2012年 | 61篇 |
2011年 | 78篇 |
2010年 | 40篇 |
2009年 | 37篇 |
2008年 | 54篇 |
2007年 | 69篇 |
2006年 | 67篇 |
2005年 | 56篇 |
2004年 | 64篇 |
2003年 | 31篇 |
2002年 | 36篇 |
2001年 | 29篇 |
2000年 | 23篇 |
1999年 | 23篇 |
1998年 | 20篇 |
1997年 | 18篇 |
1996年 | 24篇 |
1995年 | 19篇 |
1994年 | 35篇 |
1993年 | 31篇 |
1992年 | 19篇 |
1991年 | 25篇 |
1990年 | 33篇 |
1989年 | 18篇 |
1988年 | 28篇 |
1987年 | 17篇 |
1986年 | 19篇 |
1985年 | 31篇 |
1984年 | 25篇 |
1983年 | 14篇 |
1982年 | 20篇 |
1981年 | 25篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 16篇 |
1977年 | 10篇 |
1976年 | 19篇 |
1975年 | 9篇 |
1974年 | 17篇 |
1973年 | 14篇 |
1972年 | 9篇 |
1969年 | 8篇 |
排序方式: 共有1467条查询结果,搜索用时 31 毫秒
101.
The exact solutions are given of the relativistic equations of motion for both the momentum and displacement of a charged particle which is injected into an arbitrary number of intense electromagnetic waves of any polarization and frequency, including zero, all of which propagate parallel to a uniform magnetostatic field with the speed of light. The solutions are implicit in time. 相似文献
102.
103.
G. W. Stewart 《Numerische Mathematik》1969,13(5):458-470
104.
V.J. Howard J.A. Edgington S.S.Das Gupta I.M. Blair B.E. Bonner F.P. Brady M.W. McNaughton N.M. Stewart 《Nuclear Physics A》1974,218(1):140-150
We have measured the np (nd) elastic scattering cross sections at 25(17) angles in the interval 30°–168° (c.m.), using a neutron beam with a broad spectrum peaked near 130 MeV. At backward angles the outgoing charged particles from a liquid hydrogen (deuterium) target were detected; at forward angles we detected neutrons scattered from a hydrogenated (deuterated) scintillating target. Cross sections have been normalized to the energy dependent solution of the Livermore nucleon-nucleon partial wave analysis, evaluated at 130 MeV. The np measurements represent a marginal improvement on previous work; the nd cross sections show some differences from pd measurements, in agreement with earlier indications at an energy of 152 MeV. 相似文献
105.
We derive two generating functions and an explicit formula for the polynomials {Hn(x)} studied by Dumont. 相似文献
106.
The specific heat of A-15 Nb3Al.83Ge.21 with a transition temperature, Tc, of 20.0 K has been measured from 6 to 25 K. Values of the parameters derived from the data are γ=35.0±2 mJ/mole-K2; the Debye temperature, θD=278±5 K; the energy gap, △, normalized as 2△/kTc, is 4.9±.3, and the thermodynamic critical field, Hc(0), is 4700±300 Gauss. 相似文献
107.
Toader AM Goff JP Roger M Shannon N Stewart JR Enderle M 《Physical review letters》2005,94(19):197202
Spin correlations in the paramagnetic phase of La(2)CuO(4) have been studied using polarized neutron scattering, with two important results. First, the temperature dependence of the characteristic energy scale of the fluctuations and the amplitude of the neutron structure factor are shown to be in quantitative agreement with the predictions of the quantum nonlinear sigma model. Second, a comparison of a high-temperature series expansion of the equal-time spin correlations with the diffuse neutron intensity provides definitive experimental evidence for ring exchange. 相似文献
108.
A precision method for determining |V(ub)| using the full range in q(2) of B --> pilnu data is presented. At large q(2) the form factor is taken from unquenched lattice QCD, at q(2) = 0 we impose a model independent constraint obtained from B --> pipi using the soft-collinear effective theory, and the shape is constrained using QCD dispersion relations. We find |V(ub)| = (3.54 +/- 0.170 +/- 0.44) x 10(-3). With 5% experimental error and 12% theory error, this is competitive with inclusive methods. Theory error is dominated by the input points, with negligible uncertainty from the dispersion relations. 相似文献
109.
Küchler R Gegenwart P Heuser K Scheidt EW Stewart GR Steglich F 《Physical review letters》2004,93(9):096402
The heavy-fermion system CeCu6-xAgx is studied at its antiferromagnetic quantum critical point, xc=0.2, by low-temperature (T> or =50 mK) specific heat, C(T), and volume thermal expansion, beta(T), measurements. Whereas C/T proportional to log((T0/T) would be compatible with the predictions of the itinerant spin-density-wave (SDW) theory for two-dimensional critical spin fluctuations, beta(T)/T and the Grüneisen ratio, Gamma(T) proportional to beta/C, diverge much weaker than expected, in strong contrast to this model. Both C and beta, plotted as a function of the reduced temperature t=T/T0 with T0=4.6 K, are similar to what was observed for YbRh2(Si(0.95)Ge(0.05))2 (T0=23.3 K), indicating a striking discrepancy to the SDW prediction in both systems. 相似文献
110.
This paper investigates the microscopic features which occur when a four-layered film is ablated using Q-switched Nd:YAG laser. The four-layered films consist of a vacuum-deposited aluminium layer (0.02 μm) upon an oriented polypropylene (OPP) film (30 μm) which has been laminated using an inert adhesive and a second OPP film. Laser radiation is absorbed principally by the aluminium layer, melting and/or vaporising it. Upon cooling, the aluminium layer is rearranged into discrete microscopic particles, which give laser-treated areas of the film a transparent appearance. Within the films are found microscopic features, which can be divided into three distinct types: aluminium demetallisation features, polymer distortion features and particle features. Features from each of these categories can exist within a single laser track depending upon the laser parameters used for transparentisation. 相似文献