全文获取类型
收费全文 | 485篇 |
免费 | 1篇 |
专业分类
化学 | 128篇 |
晶体学 | 5篇 |
力学 | 68篇 |
数学 | 46篇 |
物理学 | 239篇 |
出版年
2021年 | 4篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 19篇 |
2015年 | 3篇 |
2014年 | 23篇 |
2013年 | 21篇 |
2012年 | 20篇 |
2011年 | 17篇 |
2010年 | 23篇 |
2009年 | 22篇 |
2008年 | 23篇 |
2007年 | 19篇 |
2006年 | 23篇 |
2005年 | 21篇 |
2004年 | 16篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 14篇 |
2000年 | 16篇 |
1999年 | 9篇 |
1998年 | 12篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1966年 | 3篇 |
1917年 | 1篇 |
排序方式: 共有486条查询结果,搜索用时 265 毫秒
51.
A. V. Ustinov 《Proceedings of the Steklov Institute of Mathematics》2012,276(1):275-282
Using a geometric interpretation of continued fractions, we give a new proof of R?dseth’s formula for Frobenius numbers. 相似文献
52.
A physical realization is presented for the integrable modified sine-Gordon equation. In this case, this equation describes the propagation of an extremely short vector electromagnetic pulse in the system of asymmetric quantum objects that have permanent dipole moments in the self-energy states. Using soliton solutions for ordinary and extraordinary components, new regimes of the dynamics of the pulse and medium that are specific only to asymmetric media have been found. 相似文献
53.
We study the interaction between longitudinal-transverse acoustic pulses and a system of paramagnetic impurities with the
effective spin S = 1 in a statically deformed crystal. We show that the dynamics of a pulse propagating at an arbitrary angle
to the static-deformation direction and of the effective spins satisfy the modified reduced Maxwell-Bloch equations and, if
the spectrum of the acoustic pulse overlaps the quantum transitions between spin sublevels, the modified sine-Gordon equation.
These equations generalize the well-known models in the theory of the inverse scattering method and in the theory of self-induced
transparency and also belong to the class of integrable equations. Analyzing soliton solutions shows that the pulse-medium
interaction reveals some qualitatively new features in these models compared with the cases of purely transverse or purely
longitudinal acoustic fields.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 151, No. 2, pp. 228–247, May, 2007. 相似文献
54.
G. M. Ustinov 《Siberian Mathematical Journal》1995,36(4):792-799
Translated fromSibirskii Matematicheskii Zhurnal, Vol. 36, No. 4, pp. 917–926, July–August, 1995. 相似文献
55.
E. Yu. Lundina Yu. M. Shernyakov M. V. Maksimov I. N. Kayander A. F. Tsatsul’nikov N. N. Ledentsov A. E. Zhukov N. A. Maleev S. S. Mikhrin V. M. Ustinov Zh. I. Alferov D. Bimberg 《Technical Physics》2003,48(1):131-132
Accelerated degradation testing of long-wavelength (>1.25 µm) quantum-dot lasers made on GaAs substrates is carried out at a fixed current of 1.7 A, initial optical output of about 0.3 W, and a heat sink temperature of 60°C. No signs of degradation are revealed after testing for 450 h. The test bed is not sealed, inert gas purging is not performed, and the laser faces are not passivated. 相似文献
56.
C. Guasch C.M. Sotomayor Torres N.N. Ledentsov D. Bimberg V.M. Ustinov P.S. Kop'ev 《Superlattices and Microstructures》1997,21(4):509-516
Resonant luminescence studies of InAs quantum dots (QDs) embedded in a GaAs matrix grown by molecular beam epitaxy are presented, showing marked differences for modulation-doped and undoped QDs and indicating that the doping leads to different exciton formation and carrier relaxation mechanisms. The LO-phonon assisted relaxatioin of excitons between sub-levels is identified for the modulation-doped QDs. 相似文献
57.
M. V. Ustinov 《Fluid Dynamics》1995,30(4):523-529
Direct numerical simulation is used to investigate laminar-turbulent transition in a boundary layer with a span-periodic inhomogeneity of the velocity profile which is created artificially. It is shown that the presence of the inhomogeneity leads to a slowing down of the growth of unstable perturbations and a delaying of the laminar-turbulent transition.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 45–52, July–August, 1995. 相似文献
58.
M. V. Ustinov 《Fluid Dynamics》2004,39(2):260-274
The disturbances generated by external turbulence in the boundary layer on a flat plate set suddenly in motion are determined. A turbulent flow calculated by direct numerical simulation is taken as the initial conditions. The solution obtained simulates the initial stage of laminar-turbulent transition in the flat-plate boundary layer at a high turbulence level in the oncoming flow. The solution makes it possible to estimate the effects of different factors, such as nonstationarity, nonlinearity, and the parameters of the freestream velocity fluctuation spectrum, on disturbance enhancement in the boundary layer. 相似文献
59.
The pulsating regime produced by the presence of a cylindrical cavity in a stationary inhomogeneous supersonic flow is simulated mathematically. The system of equations for an inviscid thermally nonconducting gas is solved by a numerical method based on a two-step difference scheme of second order of approximation. This method makes it possible to calculate in each time step the complete flow field at once, which makes it possible to follow the development of the nonstationary flow, which in the present case is a pulsating flow. The flow pattern in the pulsating regime is studied in detail. The pressure pulsations in the cavity are due to the alternating passage through it of shock waves and rarefaction waves, and the pulsations are nonlinear. The influence of the basic parameters on the characteristics of the pulsating flow is studied and some estimates are made.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 64–71, September–October, 1979. 相似文献
60.
M. V. Ustinov 《Fluid Dynamics》1998,33(6):856-863
The linear stability of a boundary layer flow with a spanwise-periodic nonuniformity in the velocity profile is investigated.
This flow can be considered as a model of a streaky structure occurring in the boundary layer at a high freestream turbulence
level. It is shown that for a small nonuniformity amplitude symmetric modes similar to Tollmien-Schlichting waves are the
most unstable. At higher nonuniformity amplitudes, antisymmetric modes, qualitatively different from Tollmien-Schlichting
waves and having a larger phase velocity, are the most amplified.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 54–63, November–December,
1998.
The study was carried out with the support of the International Scientific and Technical Center (project No. 199-95) and the
Russian Foundation for Basic Research (project No. 95-01-01201a). 相似文献