全文获取类型
收费全文 | 149篇 |
免费 | 8篇 |
专业分类
化学 | 91篇 |
力学 | 9篇 |
数学 | 19篇 |
物理学 | 38篇 |
出版年
2022年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 11篇 |
2011年 | 8篇 |
2010年 | 10篇 |
2009年 | 3篇 |
2008年 | 11篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 5篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 31 毫秒
91.
Boutaghane N Kabouche A Touzani R Maklad YA El-Azzouny A Bruneau C Kabouche Z 《Natural product communications》2011,6(2):251-252
The essential oil of Matricaria pubescens (Asteraceae) collected at Ghardaia (Algerian Septentrional Sahara) was studied by GC and GC-MS. Isochrysanthemic acid ethyl ester (26.5%), spathulenol (19.4%), alpha-cadinol (12.9%) and geranylisovalerate (8.2%), were identified as the major components of the essential oil, which was investigated for its analgesic effect. 相似文献
92.
Front‐tracking by the level‐set and the volume penalization methods in a two‐phase microfluidic network 下载免费PDF全文
Two‐phase immiscible fluids in a two‐dimensional micro‐channels network are considered. The incompressible Stokes equations are used to describe the Newtonian fluid flow, while the Oldroyd‐B rheological model is used to capture the viscoelastic behavior. In order to perform numerical simulations in a complex geometry like a micro‐channels network, the volume penalization method is implemented. To follow the interface between the two fluids, the level‐set method is used, and the dynamics of the contact line is modeled by Cox law. Numerical results show the ability of the method to simulate two‐phase flows and to follow properly the contact line between the two immiscible fluids. Finally, simulations with realistic parameters are performed to show the difference when a Newtonian fluid is pushed by a viscoelastic fluid instead of a Newtonian one. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
93.
Laurent Bruneau Vojkan Jakšić Yoram Last Claude-Alain Pillet 《Letters in Mathematical Physics》2016,106(6):787-797
We characterize the absolutely continuous spectrum of half-line one-dimensional Schrödinger operators in terms of the limiting behavior of the crystalline Landauer–Büttiker conductance of the associated finite samples. 相似文献
94.
Laurent Bruneau 《Journal of statistical physics》2014,155(5):888-908
We study the relaxation properties of the quantized electromagnetic field in a cavity under repeated interactions with single two-level atoms, so-called one-atom maser. We improve the ergodic results obtained in Bruneau and Pillet (J Stat Phys 134(5–6):1071–1095, 2009) and prove that, whenever the atoms are initially distributed according to the canonical ensemble at temperature $T>0$ , all the invariant states are mixing. Under some non-resonance condition this invariant state is known to be thermal equilibirum at some renormalized temperature $T^*$ and we prove that the mixing is then arbitrarily slow, in other words that there is no lower bound on the relaxation speed. 相似文献
95.
96.
Herein we report a one-pot catalytic asymmetric reductive amination of 2-tetralone. High-throughput screening of a small library of chiral ligands allowed us to perform the enantioselective hydrogenation of the intermediate enamine with up to 60% ee and a one-pot reaction with up to 47% enantiomeric excess of the desired amine. 相似文献
97.
98.
E. Espinosa B. Wyncke F. Bréhat X. Gerbaux S. Veintemillas E. Molins 《Infrared Physics & Technology》1997,38(7):449-458
The entire vibrational spectrum of a single crystal of l-histidinium dihydrogen orthophosphate orthophosphoric acid (LHP) was studied by infrared (IR) spectroscopy from 10 up to 4000 cm−1. The polarized infrared (IR) reflectivity spectra were measured between 7 and 250 K, in the frequency range 10–600 cm−1. From the IR spectral analysis, the phonon modes were classified within their symmetry species, and their longitudinal (LO) and transversal (TO) optical frequencies were calculated. A tentative assignment of the various internal modes observed in the transmissivity spectrum of LHP, between 300 and 4000 cm−1, is proposed. The present study did not reveal any low-temperature structural phase transition. 相似文献
99.
The aim of this paper is to give open boundary conditions for the incompressible Navier–Stokes equations. From a weak formulation in velocity–pressure variables, some natural boundary conditions involving the traction or pseudotraction and inertial terms are established. Numerical experiments on the flow behind a cylinder show the efficiency of these conditions, which convey properly the vortices downstream. Comparisons with other boundary conditions for the velocity and pressure are also performed. 相似文献
100.
This paper describes a CW submillimeter waveguide laser operating on 190 and 195 μm DCN lines with high volumetric efficiency. The laser cavity is a 3.2 cm inner diameter, 70 cm long, Pyrex tube with plane reflectors (one of them is a copper mesh) against its ends. After optimization of various parameters (such as the N2:CD4:He gas mixture, the pressure and the discharge current, the wall temperature and the output coupling), this laser, with only 57 cm long active discharge, delivers 8.4 and 7.6 mW on the 190 and 195 μm lines, respectively, for the EH11 mode. This represents volumetric powers of 75 and 65 μW cm-3. The free space propagation of the EH11 fundamental mode was found to be as for a gaussian beam, and the absorption of the laser beam in the atmosphere was also measured. 相似文献