全文获取类型
收费全文 | 48003篇 |
免费 | 8074篇 |
国内免费 | 5240篇 |
专业分类
化学 | 32635篇 |
晶体学 | 497篇 |
力学 | 3225篇 |
综合类 | 449篇 |
数学 | 5954篇 |
物理学 | 18557篇 |
出版年
2024年 | 44篇 |
2023年 | 1009篇 |
2022年 | 1089篇 |
2021年 | 1431篇 |
2020年 | 1999篇 |
2019年 | 1829篇 |
2018年 | 1594篇 |
2017年 | 1544篇 |
2016年 | 2275篇 |
2015年 | 2104篇 |
2014年 | 2613篇 |
2013年 | 3487篇 |
2012年 | 4267篇 |
2011年 | 4365篇 |
2010年 | 2972篇 |
2009年 | 2868篇 |
2008年 | 3164篇 |
2007年 | 2790篇 |
2006年 | 2632篇 |
2005年 | 2181篇 |
2004年 | 1690篇 |
2003年 | 1354篇 |
2002年 | 1142篇 |
2001年 | 979篇 |
2000年 | 944篇 |
1999年 | 1132篇 |
1998年 | 943篇 |
1997年 | 881篇 |
1996年 | 864篇 |
1995年 | 818篇 |
1994年 | 715篇 |
1993年 | 646篇 |
1992年 | 537篇 |
1991年 | 475篇 |
1990年 | 462篇 |
1989年 | 332篇 |
1988年 | 255篇 |
1987年 | 202篇 |
1986年 | 182篇 |
1985年 | 157篇 |
1984年 | 96篇 |
1983年 | 87篇 |
1982年 | 88篇 |
1981年 | 40篇 |
1980年 | 20篇 |
1979年 | 6篇 |
1976年 | 1篇 |
1959年 | 1篇 |
1957年 | 10篇 |
1936年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Acta Mathematicae Applicatae Sinica, English Series - So far there have been few results presented on the exponential stability for time-changed stochastic differential equations. The main aim of... 相似文献
2.
Liu Zhu Sun Wen-Yang Fan Xiao-Gang Wang Dong Ye Liu 《International Journal of Theoretical Physics》2021,60(7):2412-2422
International Journal of Theoretical Physics - In this paper, we investigate Einstein-Podolsky-Rosen steering, Bell non-locality, first-order coherence and concurrence in the spin- $\frac {1}{2}$... 相似文献
3.
Potential Analysis - The purpose of this paper is to provide necessary and sufficient conditions of the boundedness for singular integrals on the local Hardy space and its dual. Particularly the... 相似文献
4.
In this paper, we study vanishing and splitting results on a complete smooth metric measure space \((M^n,g,\mathrm {e}^{-f}\mathrm {d}v)\) with various negative m-Bakry-Émery Ricci curvature lower bounds in terms of the first eigenvalue \(\lambda _1(\Delta _f)\) of the weighted Laplacian \(\Delta _f\), i.e., \(\mathrm {Ric}_{m,n}\ge -a\lambda _1(\Delta _f)-b\) for \(0<a\le \dfrac{m}{m-1}, b\ge 0\). In particular, we consider three main cases for different a and b with or without conditions on \(\lambda _1(\Delta _f)\). These results are extensions of Dung and Vieira, and weighted generalizations of Li-Wang, Dung-Sung, and Vieira.
相似文献5.
Designs, Codes and Cryptography - Large sets of combinatorial designs has always been a fascinating topic in design theory. These designs form a partition of the whole space into combinatorial... 相似文献
6.
Nonlinear Dynamics - This article considers a reaction–diffusion predator–prey model with schooling behavior both in predator and prey species and subject to the homogeneous Neumann... 相似文献
7.
This study is to numerically test the interfacial instability of ferrofluid flow under the presence of a vacuum magnetic field. The ferrofluid parabolized stability equations(PSEs) are derived from the ferrofluid stability equations and the Rosensweig equations, and the characteristic values of the ferrofluid PSEs are given to describe the ellipticity of ferrofluid flow. Three numerical models representing specific cases considering with/without a vacuum magnetic field or viscosity are created to mathematically examine the interfacial instability by the computation of characteristic values. Numerical investigation shows strong dependence of the basic characteristic of ferrofluid Rayleigh-Taylor instability(RTI) on viscosity of ferrofluid and independence of the vacuum magnetic field.For the shock wave striking helium bubble, the magnetic field is not able to trigger the symmetry breaking of bubble but change the speed of the bubble movement. In the process of droplet formation from a submerged orifice, the collision between the droplet and the liquid surface causes symmetry breaking. Both the viscosity and the magnetic field exacerbate symmetry breaking. The computational results agree with the published experimental results. 相似文献
8.
Song Zi-Long Zhu Yun Liu Jing-Rui Guo Shu-Ke Gu Yu-Cheng Han Xinya Dong Hong-Qiang Sun Qi Zhang Wei-Hua Zhang Ming-Zhi 《Molecular diversity》2021,25(1):205-221
Molecular Diversity - Based on the strategy of diversity-oriented synthesis and the structures of natural product pimprinine and streptochlorin, two series of novel pimprinine derivatives... 相似文献
9.
Nonlinear Dynamics - The paper studies the stability and control of radial deployment of an electric solar wind sail with the consideration of high-order modes of elastic tethers. The electric... 相似文献
10.
Chinese Journal of Polymer Science - The emerging chemical recyclable polymers, such as poly(γ-butyrolactone) (PGBL) and poly((R)-3,4-trans six-membered ring-fused GBL) (P((R)-M)), provide a... 相似文献