全文获取类型
收费全文 | 33942篇 |
免费 | 6157篇 |
国内免费 | 3670篇 |
专业分类
化学 | 24521篇 |
晶体学 | 418篇 |
力学 | 1912篇 |
综合类 | 165篇 |
数学 | 3283篇 |
物理学 | 13470篇 |
出版年
2024年 | 139篇 |
2023年 | 745篇 |
2022年 | 1362篇 |
2021年 | 1438篇 |
2020年 | 1528篇 |
2019年 | 1522篇 |
2018年 | 1293篇 |
2017年 | 1176篇 |
2016年 | 1780篇 |
2015年 | 1705篇 |
2014年 | 2151篇 |
2013年 | 2669篇 |
2012年 | 3176篇 |
2011年 | 3205篇 |
2010年 | 2096篇 |
2009年 | 2023篇 |
2008年 | 2236篇 |
2007年 | 1940篇 |
2006年 | 1754篇 |
2005年 | 1409篇 |
2004年 | 1078篇 |
2003年 | 825篇 |
2002年 | 802篇 |
2001年 | 611篇 |
2000年 | 496篇 |
1999年 | 614篇 |
1998年 | 529篇 |
1997年 | 507篇 |
1996年 | 507篇 |
1995年 | 432篇 |
1994年 | 346篇 |
1993年 | 285篇 |
1992年 | 283篇 |
1991年 | 226篇 |
1990年 | 206篇 |
1989年 | 152篇 |
1988年 | 93篇 |
1987年 | 83篇 |
1986年 | 105篇 |
1985年 | 74篇 |
1984年 | 39篇 |
1983年 | 46篇 |
1982年 | 30篇 |
1981年 | 25篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1973年 | 2篇 |
1957年 | 4篇 |
1935年 | 1篇 |
1923年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
71.
Zhao Fang BAI Jin Chuan HOU 《数学学报(英文版)》2005,21(5):1167-1182
Let X be a (real or complex) Banach space with dimension greater than 2 and let B0(X) be the subspace of B(X) spanned by all nilpotent operators on X. We get a complete classification of surjective additive maps Ф on B0(X) which preserve nilpotent operators in both directions. In particular, if X is infinite-dimensional, we prove that Ф has the form either Ф(T) = cATA^-1 or Ф(T) = cAT'A^-1, where A is an invertible bounded linear or conjugate linear operator, c is a scalar, T' denotes the adjoint of T. As an application of these results, we show that every additive surjective map on B(X) preserving spectral radius has a similar form to the above with |c| = 1. 相似文献
72.
Zhao Zheng Zhang Jian-hua Jiang Ya-ling 《International Journal of Theoretical Physics》1997,36(6):1359-1368
The Hawking effect of a nonuniformly rectilinearly accelerating Kinnersley black hole is studied. Its horizons are rotationally
symmetric. Its Hawking temperature depends not only on the time, but also on the polar angle. When a Kinnersley black hole
touches its Rindler horizon, the Hawking temperature at the contact point is reduced to zero. But at the opposite pole of
the black hole, the Hawking temperature increases rapidly. A jet appears as a tail of the accelerating black hole. 相似文献
73.
74.
L.-Q. Han S.-Y. Zhao Y.-D. Zhou P.-L. Zhang 《Applied physics. B, Lasers and optics》1997,65(3):399-402
Received: 18 June 1996/Revised version: 3 January 1997 相似文献
75.
Zhao Xuelei 《数学年刊B辑(英文版)》1997,18(1):47-54
GIRSANOV’STHEOREMONABSTRACTWIENERSPACESZHANGYINNANAbstractLet(E,H,μ)beanabstractWienerspaceinthesenseofL.Gros.Itisprovedth... 相似文献
76.
77.
78.
V.I. Fernández A. Iucci C.M. Naón 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(1):53-56
We present an extension of the Tomonaga-Luttinger model in which left and right-moving particles have different Fermi velocities.
We derive expressions for one-particle Green's functions, momentum-distributions, density of states, charge compressibility
and conductivity as functions of both the velocity difference ε and the strength of the interaction β. This allows us to identify
a novel restricted region in the parameter space in which the system keeps the main features of a Luttinger liquid but with
an unusual behavior of the density of states and the static charge compressibility κ. In particular κ diverges on the boundary
of the restricted region, indicating the occurrence of a phase transition.
Received 20 May 2002 / Received in final form 23 August 2002 Published online 19 November 2002 相似文献
79.
Tao Liu Zuxiong Xu Zhongtao Zhao Ruzhang Ma Tiandou Hu Yaning Xie Yinghuan Guo 《中国科学A辑(英文版)》1997,40(4):395-399
The role of magnetoelastic coupling effects in nanocrystalline ferromagnets is investigated by means of high-field magnetization and Doppler-broadening spectrum measurements. For the nanocrystalline Fe73 5Cu1Nb3Si13.5B9 alloy, the results show that the pinning effects resulting from the quasidislocation dipole intensely influence the movement of domain wall; by coupling with the magnetostriction the defects-induced stress fields determine the magnetic properties at the early stage of crystallization. In view of the effective anisotropy and magnetoelastic coupling energy the optimal annealing conditions of alloys are discussed. 相似文献
80.
本文通过对大量的黄酮类化合物13C NMR图谱的分析和研究,总结了不同类型的黄酮类化合物的13C NMR图谱特征及化学位移规律.对影响黄酮类化合物结构骨架上不同位置碳原子化学位移的因素进行了分析,建立了用于黄酮类天然产物13C NMR图谱智能解析的知识库. 相似文献