全文获取类型
收费全文 | 423702篇 |
免费 | 18842篇 |
国内免费 | 12567篇 |
专业分类
化学 | 218121篇 |
晶体学 | 6381篇 |
力学 | 22857篇 |
综合类 | 667篇 |
数学 | 61434篇 |
物理学 | 145651篇 |
出版年
2022年 | 4686篇 |
2021年 | 5111篇 |
2020年 | 5857篇 |
2019年 | 5880篇 |
2018年 | 14392篇 |
2017年 | 14830篇 |
2016年 | 12441篇 |
2015年 | 7828篇 |
2014年 | 9800篇 |
2013年 | 17614篇 |
2012年 | 20476篇 |
2011年 | 30230篇 |
2010年 | 19879篇 |
2009年 | 19658篇 |
2008年 | 25100篇 |
2007年 | 27716篇 |
2006年 | 13892篇 |
2005年 | 18337篇 |
2004年 | 13612篇 |
2003年 | 12177篇 |
2002年 | 9997篇 |
2001年 | 9369篇 |
2000年 | 7536篇 |
1999年 | 6292篇 |
1998年 | 5302篇 |
1997年 | 5016篇 |
1996年 | 4999篇 |
1995年 | 4460篇 |
1994年 | 4261篇 |
1993年 | 4094篇 |
1992年 | 4104篇 |
1991年 | 4163篇 |
1990年 | 3786篇 |
1989年 | 3590篇 |
1988年 | 3526篇 |
1987年 | 3370篇 |
1986年 | 3202篇 |
1985年 | 4149篇 |
1984年 | 4293篇 |
1983年 | 3434篇 |
1982年 | 3615篇 |
1981年 | 3494篇 |
1980年 | 3370篇 |
1979年 | 3461篇 |
1978年 | 3555篇 |
1977年 | 3399篇 |
1976年 | 3526篇 |
1975年 | 3210篇 |
1974年 | 3199篇 |
1973年 | 3294篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Applied Mathematics and Mechanics - Spiral springs have a wide range of applications in various fields. As a result of the complexity of friction, few theoretical analyses of spring belts under... 相似文献
22.
Machado J. A. Tenreiro Rocha-Neves J. M. Azevedo Filipe Andrade J. P. 《Nonlinear dynamics》2021,106(2):1525-1555
Nonlinear Dynamics - Given a data-set of Ribonucleic acid (RNA) sequences we can infer the phylogenetics of the samples and tackle the information for scientific purposes. Based on current data and... 相似文献
23.
Theoretical and Mathematical Physics - We consider three one-dimensional superconducting structures: 1) the one with $$p$$ -wave superconductivity; 2) the main experimental model of a nanowire with... 相似文献
24.
Zadeba E. A. Khokhlov S. S. Kokoulin R. P. Petrukhin A. A. Shulzhenko I. A. Yashin I. I. 《Physics of Atomic Nuclei》2022,85(1):86-91
Physics of Atomic Nuclei - The muon puzzle is an excess of muon bundles generated by primary cosmic rays (PCR) at energies above 10 $${}^{17}$$ eV compared to estimations that assume even a heavy... 相似文献
25.
26.
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
27.
Liu Jun-Wei Shen Shu-Qian Li Ming Li Lei 《International Journal of Theoretical Physics》2021,60(5):1712-1719
International Journal of Theoretical Physics - Quantum coherence, coming from quantum superposition, occupies a significant position in the field of physics. We put forward a lower bound of the... 相似文献
28.
Kuz’mina L. G. Navasardyan M. A. Kalle P. Bezzubov S. I. 《Crystallography Reports》2021,66(3):420-423
Crystallography Reports - The crystal and molecular structures of Cl–C6H4–O–C16H33 (I) have been studied, and its differential scanning calorimetry (DSC) study is performed.... 相似文献
29.
Journal of Visualization - Forecast calibration methods based on historical similar atmospheric state are effective means weather forecast accuracy. Conventional approaches search similar forecasts... 相似文献
30.
Journal of Applied Mechanics and Technical Physics - A refined model of viscoelastic-plastic deformation of flexible plates with spatial reinforcement structures has been developed. Strains of the... 相似文献