全文获取类型
收费全文 | 530883篇 |
免费 | 4242篇 |
国内免费 | 1308篇 |
专业分类
化学 | 270336篇 |
晶体学 | 7687篇 |
力学 | 26080篇 |
综合类 | 18篇 |
数学 | 68283篇 |
物理学 | 164029篇 |
出版年
2021年 | 5079篇 |
2020年 | 5536篇 |
2019年 | 6287篇 |
2018年 | 8517篇 |
2017年 | 8667篇 |
2016年 | 11750篇 |
2015年 | 6262篇 |
2014年 | 10565篇 |
2013年 | 23762篇 |
2012年 | 18498篇 |
2011年 | 21937篇 |
2010年 | 16561篇 |
2009年 | 16373篇 |
2008年 | 20796篇 |
2007年 | 20633篇 |
2006年 | 18697篇 |
2005年 | 16670篇 |
2004年 | 15520篇 |
2003年 | 14003篇 |
2002年 | 13884篇 |
2001年 | 14748篇 |
2000年 | 11369篇 |
1999年 | 8769篇 |
1998年 | 7619篇 |
1997年 | 7482篇 |
1996年 | 6949篇 |
1995年 | 6272篇 |
1994年 | 6277篇 |
1993年 | 6022篇 |
1992年 | 6380篇 |
1991年 | 6873篇 |
1990年 | 6581篇 |
1989年 | 6490篇 |
1988年 | 6323篇 |
1987年 | 6135篇 |
1986年 | 5875篇 |
1985年 | 7413篇 |
1984年 | 7780篇 |
1983年 | 6533篇 |
1982年 | 6823篇 |
1981年 | 6331篇 |
1980年 | 6010篇 |
1979年 | 6510篇 |
1978年 | 6747篇 |
1977年 | 6631篇 |
1976年 | 6590篇 |
1975年 | 6308篇 |
1974年 | 6132篇 |
1973年 | 6424篇 |
1972年 | 4710篇 |
排序方式: 共有10000条查询结果,搜索用时 73 毫秒
861.
862.
863.
All the symmetries and conservation laws of Navier-Stokes equations are calculated. 相似文献
864.
A. I. Zaslavskii 《Theoretical and Mathematical Physics》1989,80(3):935-941
Nizhnetagil' State Pedagogical Institute. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 80, No. 3, pp. 372–380, September, 1989. 相似文献
865.
V. A. Shlyk 《Ukrainian Mathematical Journal》1989,41(3):361-364
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 41, No. 3, pp. 408–412, March, 1989. 相似文献
866.
867.
It is shown, using a Born-Oppenheimer model, that the four-body Efimov effect may occur in a system consisting of three identical heavy particles and one light particle, if the light-heavy interaction leads to a zeroenergy two-heavy-one-light bound state. 相似文献
868.
Spatio temporal dynamics of the positive column of a dc neon glow discharge is studied and investigated experimentally and theoretically. Spatio temporal analysis by means of biorthogonal decomposition method (BOD) gives insights into the mechanism of irregularity and can be employed for characterization of spatio‐ temporal complexity. In the weak nonlinear region, the wave dynamics is approximated by an amplitude equation of the Ginzburg‐Landau equation (CGLE) with complex coefficients and an additional integral term based on a fluid model. In the present work we deal with irregular spatio‐temporal data. A comparison between the numerical analysis of the experimental data and simulation results are studied. A good agreement between the dynamical behaviour for experimental space‐time data and theoretical simulation space‐time results was obtained. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
869.
A Howie 《Microscopy and microanalysis》2004,10(1):28-33
The key contribution of electron microscopy methods to condensed matter spectroscopy is undoubtedly spatial resolution. So far this has mainly been manifest through electron energy loss spectroscopy in the 1-eV to 10-keV energy range and has not seriously challenged the dominance of optical, X-ray, and neutron spectroscopy methods over most of the vast field at lower energies. At frequencies up to a few megahertz, corresponding to energies of a few nanoelectron volts and below, direct excitation by pulsed electron beams or electric fields has proved effective. Prospects are discussed for extending spatially resolved spectroscopy to the intermediate energy region, mainly by combining the advantages of electrons with those of photons. 相似文献
870.
Modification of shungite with polyamines, followed by corss-linking with epoxy compounds, yielded chemically and thermally stable polyfunctional anion exchangers. The effect of the nature of a polyamine and epoxy compounds and of the carbon content of shungites and the process conditions on the ion-exchange properties of the samples obtained was studied. 相似文献