全文获取类型
收费全文 | 3632篇 |
免费 | 632篇 |
国内免费 | 776篇 |
专业分类
化学 | 37篇 |
力学 | 59篇 |
综合类 | 232篇 |
数学 | 3737篇 |
物理学 | 975篇 |
出版年
2024年 | 15篇 |
2023年 | 53篇 |
2022年 | 53篇 |
2021年 | 61篇 |
2020年 | 33篇 |
2019年 | 49篇 |
2018年 | 30篇 |
2017年 | 74篇 |
2016年 | 68篇 |
2015年 | 102篇 |
2014年 | 215篇 |
2013年 | 140篇 |
2012年 | 246篇 |
2011年 | 274篇 |
2010年 | 259篇 |
2009年 | 225篇 |
2008年 | 312篇 |
2007年 | 261篇 |
2006年 | 239篇 |
2005年 | 212篇 |
2004年 | 231篇 |
2003年 | 196篇 |
2002年 | 205篇 |
2001年 | 191篇 |
2000年 | 211篇 |
1999年 | 133篇 |
1998年 | 140篇 |
1997年 | 141篇 |
1996年 | 109篇 |
1995年 | 124篇 |
1994年 | 94篇 |
1993年 | 83篇 |
1992年 | 71篇 |
1991年 | 49篇 |
1990年 | 62篇 |
1989年 | 51篇 |
1988年 | 17篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有5040条查询结果,搜索用时 15 毫秒
201.
202.
We derive the basic canonical brackets amongst the creation and annihilation operators for a two (1 + 1)- dimensional (2D) gauge field theoretic model of an interacting Hodge theory where a U(1) gauge field (Aμ) is coupled with the fermionic Dirac fields (ψ and ψ). In this derivation, we exploit the spin-statistics theorem, normal ordering and the strength of the underlying six infinitesimal continuous symmetries (and the concept of their generators) that are present in the theory. We do not use the definition of the canonical conjugate momenta (corresponding to the basic fields of the theory) anywhere in our whole discussion. Thus, we conjecture that our present approach provides an alternative to the canonical method of quantization for a class of gauge field theories that are physical examples of Hodge theory where the continuous symmetries (and corresponding generators) provide the physical realizations of the de Rham cohomological operators of differential geometry at the algebraic level. 相似文献
203.
Teng Xia Ju 《数学学报(英文版)》2009,25(5):831-844
In this paper, we show that if H is a finite-dimensional Hopf algebra such that H and H^* are semisimple, then gl.dim(A#σH)=gl.dim(A), where a is a convolution invertible cocycle. We also discuss the relationship of global dimensions between the crossed product A^#σH and the algebra A, where A is coacted by H. Dually, we give a sufficient condition for a finite dimensional coalgebra C and a finite dimensional semisimple Hopf algebra H such that gl.dim(C α H)=gl.dim(C). 相似文献
204.
Evolution of Number State to Density Operator of Binomial Distribution in the Amplitude Dissipative Channel 下载免费PDF全文
We show that passing through the amplitude dissipative channel the initial pure number state density operator is evolved into the density operator of binomial distribution (a mixed state), and the binomial distribution parameter is just equal to e^-2kt, where k is the dissipative parameter of the channel. We solve the corresponding master equation to obtain the operator-sum representation of the density operator by virtue of the entangled state representation, which seems to be a convenient approach. 相似文献
205.
206.
提出了极大加代数上可约矩阵特征值的缺失值及冗余值的概念,得到了相应的定理;对特征值与周期时间向量分量之间的关系作了深入的研究. 相似文献
207.
208.
针对光催化制氢反应器内液固两相流的特点,运用代数滑移模型,对反应器内的催化剂颗粒-水两相流动进行了数值模拟。采用分块的结构化网格,并运用多重网格方法进行求解。通过与前人实验中压力梯度结果的比较,对模型进行了验证,并最终得到了反应器内催化剂颗粒的典型分布及相应的类型图。 相似文献
209.
The multicomponent (2+1)-dimensional Glachette-Johnson (GJ) equation hierarchy and its super-integrable coupling system 下载免费PDF全文
This paper presents a set of multicomponent matrix Lie algebra, which is used to construct a new loop algebra A^-M. By using the Tu scheme, a Liouville integrable multicomponent equation hierarchy is generated, which possesses the Hamiltonian structure. As its reduction cases, the multicomponent (2+1)-dimensional Glachette-Johnson (G J) hierarchy is given. Finally, the super-integrable coupling system of multicomponent (2+1)-dimensional GJ hierarchy is established through enlarging the spectral problem. 相似文献
210.
Based on some known facts of integrable models, this paper proposes a new (2+1)-dimensional bilinear model equation. By virtue of the formal series symmetry approach, the new model is proved to be integrable because of the existence of the higher order symmetries. The Lie point symmetries of the model constitute an infinite dimensional Kac- Moody Virasoro symmetry algebra. Making use of the infinite Lie point symmetries, the possible symmetry reductions of the model are also studied 相似文献