全文获取类型
收费全文 | 7284篇 |
免费 | 1418篇 |
国内免费 | 3985篇 |
专业分类
化学 | 6877篇 |
晶体学 | 127篇 |
力学 | 199篇 |
综合类 | 327篇 |
数学 | 1715篇 |
物理学 | 3442篇 |
出版年
2024年 | 35篇 |
2023年 | 139篇 |
2022年 | 219篇 |
2021年 | 250篇 |
2020年 | 211篇 |
2019年 | 239篇 |
2018年 | 147篇 |
2017年 | 210篇 |
2016年 | 284篇 |
2015年 | 271篇 |
2014年 | 313篇 |
2013年 | 470篇 |
2012年 | 520篇 |
2011年 | 462篇 |
2010年 | 532篇 |
2009年 | 525篇 |
2008年 | 634篇 |
2007年 | 616篇 |
2006年 | 705篇 |
2005年 | 611篇 |
2004年 | 752篇 |
2003年 | 648篇 |
2002年 | 603篇 |
2001年 | 535篇 |
2000年 | 366篇 |
1999年 | 406篇 |
1998年 | 308篇 |
1997年 | 211篇 |
1996年 | 200篇 |
1995年 | 220篇 |
1994年 | 209篇 |
1993年 | 139篇 |
1992年 | 169篇 |
1991年 | 142篇 |
1990年 | 131篇 |
1989年 | 142篇 |
1988年 | 66篇 |
1987年 | 22篇 |
1986年 | 11篇 |
1985年 | 6篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1980年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
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
92.
93.
We explore the spin-boson model in a special case, i.e., with zero local field. In contrast to previous studies, we find no possibility for quantum phase transition (QPT) happening between the localized and delocalized phases, and the behavior of the model can be fully characterized by the even or odd parity as well as the parity breaking, instead of the QPT, owned by the ground state of the system. The parity breaking mentioned in our case is completely different from the spontaneously broken symmetry relevant to the conventionally defined QPT in previous studies. Our analytical treatment about the eigensolution of the ground state of the model presents for the first time a rigorous proof of no- degeneracy for the ground state of the model, which is independent of the bath type, the degrees of freedom of the bath and the calculation precision. We argue that the QPT mentioned previously appears due to incorrect employment of the ground state of the model and/or unreasonable treatment of the infrared divergence existing in the spectral functions for Ohmic and sub-Ohmic dissipations. 相似文献
94.
95.
96.
97.
Solving (2+1)-dimensional sine-Poisson equation by a modified variable separated ordinary differential equation method 下载免费PDF全文
By introducing a more general auxiliary ordinary differential equation (ODE), a modified variable separated ordinary differential equation method is presented for solving the (2+1)-dimensional sine-Poisson equation. As a result, many explicit and exact solutions of the (2+1)-dimensional sine-Poisson equation are derived in a simple manner by this technique. 相似文献
98.
The(3+1)-dimensional Burgers equation, which describes nonlinear waves in turbulence and the interface dynamics,is considered. Two types of semi-rational solutions, namely, the lump–kink solution and the lump–two kinks solution, are constructed from the quadratic function ansatz. Some interesting features of interactions between lumps and other solitons are revealed analytically and shown graphically, such as fusion and fission processes. 相似文献
99.
100.
通过观察酸度对模拟转铁蛋白小分子EHPG和HBED紫外差光谱的影响,结合脱铁伴清蛋白与金属离子、阴离子结合的光谱特性,推断脱铁伴清蛋白与金属离子的结合导致金属离子结合位点处酪氨酸酚羟基的去质子化,而与阴离子的结合导致阴离子结合位点处酪氨酸酚羟基的质子化. 相似文献