全文获取类型
收费全文 | 1126篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学 | 354篇 |
晶体学 | 9篇 |
力学 | 79篇 |
数学 | 178篇 |
物理学 | 508篇 |
出版年
2021年 | 21篇 |
2020年 | 13篇 |
2019年 | 25篇 |
2018年 | 37篇 |
2017年 | 31篇 |
2016年 | 37篇 |
2014年 | 20篇 |
2013年 | 36篇 |
2012年 | 34篇 |
2011年 | 28篇 |
2010年 | 31篇 |
2009年 | 27篇 |
2008年 | 31篇 |
2007年 | 34篇 |
2006年 | 50篇 |
2005年 | 26篇 |
2004年 | 22篇 |
2003年 | 23篇 |
2002年 | 24篇 |
2001年 | 26篇 |
2000年 | 27篇 |
1999年 | 13篇 |
1998年 | 26篇 |
1997年 | 13篇 |
1996年 | 17篇 |
1995年 | 19篇 |
1994年 | 10篇 |
1992年 | 12篇 |
1991年 | 11篇 |
1990年 | 24篇 |
1989年 | 10篇 |
1988年 | 19篇 |
1987年 | 23篇 |
1986年 | 15篇 |
1985年 | 27篇 |
1984年 | 22篇 |
1983年 | 14篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 15篇 |
1979年 | 14篇 |
1978年 | 15篇 |
1976年 | 12篇 |
1975年 | 17篇 |
1974年 | 15篇 |
1973年 | 11篇 |
1970年 | 14篇 |
1969年 | 10篇 |
1968年 | 15篇 |
1967年 | 13篇 |
排序方式: 共有1128条查询结果,搜索用时 203 毫秒
81.
82.
S. V. Gorbunov A. F. Zatsepin V. A. Pustovarov S. O. Cholakh V. Yu. Yakovlev 《Physics of the Solid State》2005,47(4):733-737
A time-resolved cathodo-and photoluminescence study of nanostructural modifications of Al2O3 (powders and ceramics) excited by heavy-current electron beams, as well as by pulsed synchrotron radiation, is reported. It was found that Al2O3 nanopowders probed before and after Fe+ ion irradiation have the same phase composition (the γ-phase/δ-phase ratio is equal to 1), an average grain size equal to ~17 nm, and practically the same set of broad cathodoluminescence (CL) bands peaking at 2.4, 3.2, and 3.8 eV. It was established that Al2O3 nanopowders exhibit fast photoluminescence (PL) (a band at 3.2 eV), whose decay kinetics is described by two exponential stages (τ1 = 0.5 ns, τ2 = 5.5 ns). Three bands, at 5.24, 6.13, and 7.44 eV, were isolated in the excitation spectrum of the fast PL. Two alternate models of PL centers were considered, according to which the 3.2-eV luminescence either originates from radiative relaxation of the P? centers (anion-cation vacancy pairs) or is due to the formation of surface analogs of the F+ center (F S + -type centers). In addition to the fast luminescence, nano-Al2O3 was found to produce slow luminescence in the form of a broad band peaking at 3.5 eV. The excitation spectrum of the 3.5-eV luminescence obtained at T = 13 K exhibits two doublet bands with maxima at 7.8 and 8.3 eV. An analysis of the luminescent properties of nanostructural and single-crystal Al2O3 suggests that the slow luminescence of nanopowders at 3.5 eV is due to radiative annihilation of excitons localized near structural defects. 相似文献
83.
We describe how correlations between electrons can be used to trace the dynamics of correlated two-electron ionization with attosecond precision, without using attosecond pulses. The approach is illustrated using the example of Auger or Coster-Kronig decay triggered by photoionization with an extreme ultraviolet pulse. It requires correlated measurements of angle-resolved energy spectra of both the photo- and Auger electrons in the presence of a laser pulse. To reconstruct the dynamics, we use not only classical time and energy correlation, but also entanglement between the two electrons. 相似文献
84.
Fuji T Rauschenberger J Apolonski A Yakovlev VS Tempea G Udem T Gohle C Hänsch TW Lehnert W Scherer M Krausz F 《Optics letters》2005,30(3):332-334
A new scheme for stabilizing the carrier-envelope (CE) phase of a few-cycle laser pulse train is demonstrated. Self-phase modulation and difference-frequency generation in a single periodically poled lithium niobate crystal that transmits the main laser beam allows CE phase locking directly in the usable output. The monolithic scheme obviates the need for splitting off a fraction of the laser output for CE phase control, coupling into microstructured fiber, and separation and recombination of spectral components. As a consequence, the output yields 6-fs, 800-nm pulses with an unprecedented degree of short- and long-term reproducibility of the electric field waveform. 相似文献
85.
In this work the distribution of interoccurrence times between earthquakes in aftershock sequences is analyzed and a model based on a nonhomogeneous Poisson (NHP) process is proposed to quantify the observed scaling. In this model the generalized Omori's law for the decay of aftershocks is used as a time-dependent rate in the NHP process. The analytically derived distribution of interoccurrence times is applied to several major aftershock sequences in California to confirm the validity of the proposed hypothesis. 相似文献
86.
Yu. A. Kucheryaev V. G. Pal’chikov Yu. A. Pchelin Yu. L. Sokolov V. P. Yakovlev 《JETP Letters》2005,81(12):644-646
The interference of the 2P state of the hydrogen atom due to unknown long-range interaction with the metal surface (Sokolov effect) has been studied by an atomic interferometer. In contrast to previous experiments, where an atomic beam passed through slits in metal plates, a beam in the presented experiments passes at a given distance from the edges of the plates. It has been found that the interference is clearly observed if two plates are located on the same side of the beam. However, this interference disappears if one plate is displaced to the opposite side. This result cannot be explained in the framework of the available hypotheses on the nature of the effect under investigation. 相似文献
87.
Kimel AV Astakhov GV Schott GM Kirilyuk A Yakovlev DR Karczewski G Ossau W Schmidt G Molenkamp LW Rasing T 《Physical review letters》2004,92(23):237203
Static and time-resolved magneto-optical spectra of the ferromagnetic semiconductor (Ga,Mn)As show that a pulsed photoexcitation with a fluence of 10 microJ/cm(2) is equivalent to the application of an external magnetic field of about 1 mT, which relaxes with a decay time of 30 ps. This relaxation is attributed to the spin relaxation of electrons in the conduction band and is found to be not affected by interactions with Mn ions. 相似文献
88.
S. Civiš P. Kubát Z. Zelinger V. Horká A.N. Imenkov N.M. Kolchanova Y.P. Yakovlev 《Applied physics. B, Lasers and optics》2003,76(6):633-637
The article describes the manufacture and testing of a new type of semiconductor laser working at low temperatures (12–100 K)
in the wavelength range 3200–3300 cm-1. This kind of laser can be tuned in the modal range up to 6 cm-1 and is characterized by a narrow spectral line width (about 7 MHz).
Received: 12 September 2002 / Final version: 29 January 2003 / Published online: 22 May 2003
RID="*"
ID="*"Corresponding author. Fax: +420-286/591-766, E-mail: civis@jh-inst.cas.cz 相似文献
89.
J. Magyar C. Aita M. Gajdardziska-Josifovska A. Sklyarov K. Mikhaylichenko V.V. Yakovlev 《Applied Physics A: Materials Science & Processing》2003,77(2):285-291
We use short-pulse high-power lasers to selectively modify the structure of nanolaminates and nanocrystals. It is demonstrated
that femtosecond pulses can achieve excellent results for microscopic thin film removal. Laser pulses can also be used to
modify the crystal structure of thin films. It is also demonstrated that coherent laser excitation promotes a selective modification
of nanocrystals, resulting in changes of size, shape, and crystal structure.
Received: 7 October 2002 / Accepted: 20 January 2003 / Published online: 28 May 2003
RID="*"
ID="*"Corresponding author. Fax: +1-414/229-5589, E-mail: yakovlev@uwm.edu 相似文献
90.
V. E. Neuvazhaev V. G. Yakovlev 《Journal of Applied Mechanics and Technical Physics》2001,42(4):572-580
Based on the (l—v) and (k—) models, the present paper examines, both numerically and analytically, the turbulent mixing of two liquids of different densities at the interface between them for various laws of their acceleration, namely, constant, decreasing, increasing, and pulsed ones. The numerical results obtained by these models agree well with each other and with experimental data. 相似文献