全文获取类型
收费全文 | 59379篇 |
免费 | 10471篇 |
国内免费 | 1923篇 |
专业分类
化学 | 56476篇 |
晶体学 | 587篇 |
力学 | 1332篇 |
综合类 | 36篇 |
数学 | 4379篇 |
物理学 | 8963篇 |
出版年
2023年 | 198篇 |
2022年 | 364篇 |
2021年 | 836篇 |
2020年 | 1721篇 |
2019年 | 3049篇 |
2018年 | 1466篇 |
2017年 | 1077篇 |
2016年 | 4042篇 |
2015年 | 4080篇 |
2014年 | 4233篇 |
2013年 | 5487篇 |
2012年 | 4684篇 |
2011年 | 4164篇 |
2010年 | 4086篇 |
2009年 | 3899篇 |
2008年 | 3995篇 |
2007年 | 3174篇 |
2006年 | 2941篇 |
2005年 | 2840篇 |
2004年 | 2512篇 |
2003年 | 2228篇 |
2002年 | 2837篇 |
2001年 | 1924篇 |
2000年 | 1762篇 |
1999年 | 750篇 |
1998年 | 330篇 |
1997年 | 306篇 |
1996年 | 319篇 |
1995年 | 254篇 |
1994年 | 256篇 |
1993年 | 251篇 |
1992年 | 203篇 |
1991年 | 153篇 |
1990年 | 160篇 |
1989年 | 112篇 |
1988年 | 85篇 |
1987年 | 83篇 |
1986年 | 75篇 |
1985年 | 98篇 |
1984年 | 67篇 |
1983年 | 57篇 |
1982年 | 75篇 |
1981年 | 74篇 |
1979年 | 56篇 |
1978年 | 49篇 |
1977年 | 38篇 |
1976年 | 43篇 |
1975年 | 40篇 |
1974年 | 43篇 |
1973年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
981.
LetA be a finite dimensional commutative semisimple algebra over a fieldk and letV be a finitely generatedA-module. We examine the action of the general linear group GL
A
(V) on the set of flags ofk-subspaces ofV. Also, let (V, B) be a finitely generated symplectic module overA. We also investigate the action of the symplectic group Sp
A
(V, B) on the set of flags ofB-isotropick-subspaces ofV, whereB=°B is thek-symplectic form induced by a nonzerok-linear map :A k. In both cases, the orbits are completely classified in terms of certain integer invariants provided that dim
k A=2.This work is partially supported by a KOSEF research grant. 相似文献
982.
A kinetic theory for the constitutive Theological relations of rapid granular shear flow of hard circular disks, characterized by a coefficient of restitutione and a surface roughness coefficient, is formulated. From a set of general constitutive equations for single-particle dynamical variables, the approximate expressions for the limit of small and large dimensionless dissipative parameterR
t
are obtained. HereR
t
is defined as the ratio /, where is the fluctuation of translational velocity from the mean flow velocity, is the diameter of a disk, and is the shear rate. At smallR
t
the theoretical predictions can be compared with exact computer simulation results of granular dynamics that are also reported. The agreement between theory and simulation is better than expected; the present theory is accurate up to high packing density in this region ofR
t
. 相似文献
983.
Y. E. Kim M. Rabinowitz J. -H. Yoon 《International Journal of Theoretical Physics》1993,32(7):1197-1223
Previously overlooked condensed matter effects (CME) can significantly influence nuclear fusion rates in both laboratory and astrophysical environments. In dense plasmas, the ensemble of fusing particles has a significant exchange of kinetic and potential energies. Thus, there are diminished effective flux velocities resulting in a significant selective reduction of fusion rates. Our CME predictions are testable in laboratory experiments and have broad-ranging implications on the fusion rates for stellar media in general. By calculating reaction rates forp(p, e
+
v
e
) D and7Be(p, )8B in the sun, we show that CME help to solve the solar neutrino problem. 相似文献
984.
Frabetti PL Cheung HW Cumalat JP Dallapiccola C Ginkel JF Greene SV Johns WE Nehring MS Butler JN Cihangir S Gaines I Garbincius PH Garren L Gourlay SA Harding DJ Kasper P Kreymer A Lebrun P Shukla S Bianco S Fabbri FL Sarwar S Zallo A Culbertson R Gardner RW Greene R Wiss J Alimonti G Bellini G Caccianiga B Cinquini L Di Corato M Giammarchi M Inzani P Leveraro F Malvezzi S Menasce D Meroni E Moroni L Pedrini D Perasso L Sala A Sala S Torretta D Vittone M Buchholz D Claes D Gobbi B O'Reilly B 《Physical review letters》1993,71(6):827-830
985.
986.
987.
988.
Cinabro D Henderson S Kinoshita K Liu T Saulnier M Wilson R Yamamoto H Sadoff AJ Ammar R Ball S Baringer P Coppage D Copty N Davis R Hancock N Kelly M Kwak N Lam H Kubota Y Lattery M Nelson JK Patton S Perticone D Poling R Savinov V Schrenk S Wang R Alam MS Kim IJ Nemati B O'Neill JJ Romero V Severini H Sun CR Zoeller MM Crawford G Fulton R Fujino D Gan KK Kagan H Kass R Lee J Malchow R Morrow F Skovpen Y Sung M White C Whitmore J Wilson P Butler F Fu X Kalbfleisch G Lambrecht M Ross WR 《Physical review letters》1993,70(24):3700-3704
989.
Bean A Gronberg J Kutschke R Menary S Morrison RJ Nelson H Richman J Tajima H Schmidt D Sperka D Witherell M Procario M Yang S Daoudi M Ford WT Johnson DR Lingel K Lohner M Rankin P Smith JG Alexander JP Bebek C Berkelman K Besson D Browder TE Cassel DG Coffman DM Drell PS Ehrlich R Galik RS Garcia-Sciveres M Geiser B Gittelman B Gray SW Hartill DL Heltsley BK Honscheid K Jones C Kandaswamy J Katayama N Kim PC Kreinick DL Ludwig GS Masui J Mevissen J Mistry NB Ng CR Nordberg E O'Grady C 《Physical review letters》1993,70(2):138-142
990.