全文获取类型
收费全文 | 103442篇 |
免费 | 4876篇 |
国内免费 | 3204篇 |
专业分类
化学 | 41573篇 |
晶体学 | 1034篇 |
力学 | 8461篇 |
综合类 | 217篇 |
数学 | 35031篇 |
物理学 | 25206篇 |
出版年
2024年 | 70篇 |
2023年 | 572篇 |
2022年 | 1042篇 |
2021年 | 983篇 |
2020年 | 1091篇 |
2019年 | 1012篇 |
2018年 | 11110篇 |
2017年 | 10867篇 |
2016年 | 7216篇 |
2015年 | 2029篇 |
2014年 | 1750篇 |
2013年 | 2265篇 |
2012年 | 6071篇 |
2011年 | 12766篇 |
2010年 | 7158篇 |
2009年 | 7510篇 |
2008年 | 8224篇 |
2007年 | 10113篇 |
2006年 | 1566篇 |
2005年 | 2427篇 |
2004年 | 2353篇 |
2003年 | 2616篇 |
2002年 | 1610篇 |
2001年 | 756篇 |
2000年 | 801篇 |
1999年 | 778篇 |
1998年 | 716篇 |
1997年 | 666篇 |
1996年 | 681篇 |
1995年 | 579篇 |
1994年 | 459篇 |
1993年 | 437篇 |
1992年 | 337篇 |
1991年 | 313篇 |
1990年 | 287篇 |
1989年 | 244篇 |
1988年 | 203篇 |
1987年 | 181篇 |
1986年 | 150篇 |
1985年 | 140篇 |
1984年 | 105篇 |
1983年 | 86篇 |
1982年 | 93篇 |
1981年 | 60篇 |
1980年 | 58篇 |
1979年 | 46篇 |
1914年 | 45篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Sarah Peluse 《Israel Journal of Mathematics》2018,227(1):379-396
We prove that the group of diffeomorphisms of the interval [0, 1] contains surface groups whose action on (0, 1) has no global fix point and such that only countably many points of the interval (0, 1) have non-trivial stabiliser. 相似文献
13.
An approach of dynamic mesh adaptation for simulating 3‐dimensional unsteady moving‐immersed‐boundary flows 下载免费PDF全文
In this paper, we present an approach of dynamic mesh adaptation for simulating complex 3‐dimensional incompressible moving‐boundary flows by immersed boundary methods. Tetrahedral meshes are adapted by a hierarchical refining/coarsening algorithm. Regular refinement is accomplished by dividing 1 tetrahedron into 8 subcells, and irregular refinement is only for eliminating the hanging points. Merging the 8 subcells obtained by regular refinement, the mesh is coarsened. With hierarchical refining/coarsening, mesh adaptivity can be achieved by adjusting the mesh only 1 time for each adaptation period. The level difference between 2 neighboring cells never exceeds 1, and the geometrical quality of mesh does not degrade as the level of adaptive mesh increases. A predictor‐corrector scheme is introduced to eliminate the phase lag between adapted mesh and unsteady solution. The error caused by each solution transferring from the old mesh to the new adapted one is small because most of the nodes on the 2 meshes are coincident. An immersed boundary method named local domain‐free discretization is employed to solve the flow equations. Several numerical experiments have been conducted for 3‐dimensional incompressible moving‐boundary flows. By using the present approach, the number of mesh nodes is reduced greatly while the accuracy of solution can be preserved. 相似文献
14.
15.
16.
17.
Terahertz(THz) wave emission from argon atom in a two-color laser pulses is studied numerically by solving the one-dimensional(1D) time-dependent Schr ¨odinger equation. The THz spectra we obtained include both discontinuous and continuum ones. By using the special basis functions that we previously proposed, our analysis points out that the discontinuous and continuum parts are contributed by bound–bound and continuum–continuum transition of atomic energy levels. Although the atomic wave function is strongly dressed during the interaction with laser fields, our identification for the discontinuous part of the THz wave shows that the transition between highly excited bound states can still be well described by the field-free basis function in the tunneling ionization regime. 相似文献
18.
19.
20.