全文获取类型
收费全文 | 10508篇 |
免费 | 989篇 |
国内免费 | 1288篇 |
专业分类
化学 | 678篇 |
晶体学 | 16篇 |
力学 | 619篇 |
综合类 | 283篇 |
数学 | 9308篇 |
物理学 | 1881篇 |
出版年
2024年 | 9篇 |
2023年 | 118篇 |
2022年 | 107篇 |
2021年 | 165篇 |
2020年 | 200篇 |
2019年 | 248篇 |
2018年 | 230篇 |
2017年 | 273篇 |
2016年 | 294篇 |
2015年 | 231篇 |
2014年 | 466篇 |
2013年 | 696篇 |
2012年 | 422篇 |
2011年 | 619篇 |
2010年 | 578篇 |
2009年 | 762篇 |
2008年 | 826篇 |
2007年 | 885篇 |
2006年 | 707篇 |
2005年 | 659篇 |
2004年 | 488篇 |
2003年 | 558篇 |
2002年 | 478篇 |
2001年 | 369篇 |
2000年 | 413篇 |
1999年 | 377篇 |
1998年 | 352篇 |
1997年 | 283篇 |
1996年 | 206篇 |
1995年 | 114篇 |
1994年 | 123篇 |
1993年 | 74篇 |
1992年 | 56篇 |
1991年 | 52篇 |
1990年 | 40篇 |
1989年 | 26篇 |
1988年 | 31篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 36篇 |
1984年 | 32篇 |
1983年 | 13篇 |
1982年 | 28篇 |
1981年 | 15篇 |
1980年 | 19篇 |
1979年 | 19篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1936年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
11.
12.
Qian Jin Luo 《数学学报(英文版)》2020,36(6):711-722
Let B be the unit disc in R~2, H be the completion of C_0∞(B) under the norm■ .By the method of blow-up analysis and an argument of rearrangement with respect to the standard hyperbolic metric ■, we prove that, for any fixed■ ,the supremum■ .This is an analog of early results of Lu–Yang(Discrete Contin. Dyn. Syst., 2009) and Yang(Trans.Amer. Math. Soc., 2007), and extends those of Wang–Ye(Adv. Math., 2012) and Yang–Zhu(Ann.Global Anal. Geom., 2016). 相似文献
13.
14.
15.
16.
17.
Measurement Uncertainty and Its Connection to Quantum Coherence in an Inertial Unruh–DeWitt Detector
The dynamic characteristics of measured uncertainty and quantum coherence are explored for an inertial Unruh–DeWitt detector model in an expanding de Sitter space. Using the entropic uncertainty relation, the uncertainty of interest is correlated with the evolving time t, the energy level spacing δ, and the Hubble parameter H. The investigation shows that, for short time, a strong energy level spacing and small Hubble parameter can result in a relatively small uncertainty. The evolution of quantum coherence versus the evolving time and Hubble parameter, which varies almost inversely to that of the uncertainty, is then discussed, and the relationship between uncertainty and the coherence is explicitly derived. With respect to the l1 norm of coherence, it is found that the environment for the quantum system considered possesses a strong non-Markovian property. The dynamic behavior of coherence non-monotonously decreases with the growth of evolving time. The dynamic features of uncertainty and coherence in the expanding space with those in flat space are also compared. Furthermore, quantum weak measurement is utilized to effectively reduce the magnitude of uncertainty, which offers realistic and important support for quantum precision measurements during the undertaking of quantum tasks. 相似文献
18.
The Fefferman space of a contact Riemannian manifold carries a Lorentzian spin structure canonically. On the Lorentzian spin manifold, we investigate the Dirac operator and the twistor operator closely. In particular, we show that, if the contact Riemannian manifold is integrable, then there exist non-zero global solutions of the twistor equation. 相似文献
19.
We explore the non-commutative (NC) effects on the energy spectrum of a two-dimensional hydrogen atom. We consider a confined particle in a central potential and study the modified energy states of the hydrogen atom in both coordinates and momenta of non-commutativity spaces. By considering the Rashba interaction, we observe that the degeneracy of states can also be removed due to the spin of the particle in the presence of NC space. We obtain the upper bounds for both coordinates and momenta versions of NC parameters by the splitting of the energy levels in the hydrogen atom with Rashba coupling. Finally, we find a connection between the NC parameters and Lorentz violation parameters with the Rashba interaction. 相似文献
20.