全文获取类型
收费全文 | 291篇 |
免费 | 2篇 |
专业分类
化学 | 95篇 |
晶体学 | 4篇 |
力学 | 4篇 |
数学 | 2篇 |
物理学 | 188篇 |
出版年
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 4篇 |
2013年 | 10篇 |
2012年 | 14篇 |
2011年 | 19篇 |
2010年 | 12篇 |
2009年 | 13篇 |
2008年 | 7篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 13篇 |
2003年 | 12篇 |
2002年 | 7篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1976年 | 2篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1966年 | 2篇 |
1963年 | 2篇 |
1961年 | 4篇 |
1960年 | 3篇 |
排序方式: 共有293条查询结果,搜索用时 15 毫秒
51.
Aad G Abbott B Abdallah J Abdelalim AA Abdesselam A Abdinov O Abi B Abolins M Abramowicz H Abreu H Acerbi E Acharya BS Ackers M Adams DL Addy TN Adelman J Aderholz M Adomeit S Adragna P Adye T Aefsky S Aguilar-Saavedra JA Aharrouche M Ahlen SP Ahles F Ahmad A Ahsan M Aielli G Akdogan T Akesson TP Akimoto G Akimov AV Alam MS Alam MA Albrand S Aleksa M Aleksandrov IN Aleppo M Alessandria F Alexa C Alexander G Alexandre G Alexopoulos T Alhroob M Aliev M Alimonti G Alison J Aliyev M Allport PP 《Physical review letters》2010,105(25):252303
By using the ATLAS detector, observations have been made of a centrality-dependent dijet asymmetry in the collisions of lead ions at the Large Hadron Collider. In a sample of lead-lead events with a per-nucleon center of mass energy of 2.76 TeV, selected with a minimum bias trigger, jets are reconstructed in fine-grained, longitudinally segmented electromagnetic and hadronic calorimeters. The transverse energies of dijets in opposite hemispheres are observed to become systematically more unbalanced with increasing event centrality leading to a large number of events which contain highly asymmetric dijets. This is the first observation of an enhancement of events with such large dijet asymmetries, not observed in proton-proton collisions, which may point to an interpretation in terms of strong jet energy loss in a hot, dense medium. 相似文献
52.
Using the trion as an optical probe, we uncover novel electron spin dynamics in CdSe/ZnSe Stranski-Krastanov quantum dots. The longitudinal spin lifetime obeys an inverse power law associated with recharging processes in the dot ensemble. No hint at spin-orbit mediated spin relaxation is found. At very weak magnetic fields (< 50 mT), electron spin dynamics related to the hyperfine interaction with the lattice nuclei is uncovered. A strong Knight field gives rise to nuclear ordering and formation of dynamical polarization on a 100-micros time scale under continuous electron spin pumping. The associated spin transients are temperature robust and can be observed up to 100 K. 相似文献
53.
A simple technique for the study of the spatial distribution of the damage produced by ion implantation of silicon has been developed. The damage depth distribution for 40 keV boron ions in silicon has been studied at irradiation doses from 7 × 1011 to 3.9 × 1014 ions/cm2 and the relative defect peak depth R d/R p = 0.85 determined. An increase of layer conductivity as the surface part of the implanted layer is removed has been revealed. This effect is caused by the presence of radiation defects in the surface region of the layer. The “electrical” cluster diameter is about 28 A and the overlapping cluster dose is close to 1 × 1013 ions/cm2. 相似文献
54.
A. N. Matveev A. V. Sokolov A. V. Akimov V. N. Sorokin A. Yu. Samokotin N. N. Kolachevsky 《Bulletin of the Lebedev Physics Institute》2008,35(5):148-155
We consider the effect of the noise difference phase of a bichromatic field upon coherent population trapping resonances in the simplest three-level system in Λ configuration. The quasi-stationary solution of Bloch optical equations, which was found with some assumptions, shows that the presence of exciting short-correlated fluctuations of the phase of radiation reduces the contrast of the resonance line without affecting its spectral width. For the Gaussian phase noise the contrast suppression factor is χ = exp[?? rms 2 ], where ? rms 2 is phase dispersion. The experimental results obtained earlier by our group are analyzed. 相似文献
55.
S. I. Gubarev I. V. Kukushkin S. V. Tovstonog M. Yu. Akimov J. Smet K. von Klitzing W. Wegscheider 《JETP Letters》2000,72(6):324-328
Screening of excitonic states by a system of 2D electrons (or holes) in GaAs/AlGaAs single quantum wells is studied. With increasing concentration of 2D charge carriers, a threshold-type disappearance of excitonic states is observed in both luminescence and reflectance spectra. The higher the quality of the 2D system, the lower the corresponding threshold concentration. In the best systems, the collapse of excitonic states occurs at unexpectedly low electron densities n e =5×109 cm?2, which correspond to the mean dimensionless distance between the particles r s =8. This value far exceeds the threshold values observed for 3D systems (r s ≈2), as well as the values obtained for quantum wells in previous studies. The problem of measuring the concentration of low-density 2D charge carriers in photoexcitation conditions is solved by applying the method of optical detection of the dimensional magnetoplasma resonance. This method provides reliable measurements of the density of a 2D system to the values about 109 cm?2. 相似文献
56.
I. S. Kozhokaru E. T. Davletov A. V. Akimov 《Bulletin of the Lebedev Physics Institute》2017,44(9):249-253
The numerical solution to optical Bloch equations for the transition F g = 4 ? F e = 5 with a wavelength of 410.6 nmin the thulium atom is presented. The absorption spectrum saturation and narrowing effects due to optical pumping are considered in detail. 相似文献
57.
V. M. Akimov L. I. Kolesnikova L. Yu. Rusin M. B. Sevryuk J. P. Toennies 《Russian Journal of Physical Chemistry B, Focus on Physics》2009,3(5):743-752
Using the quantum mechanical path integral Monte Carlo method, we simulated parahydrogen clusters (j = 0) and clusters doped with several (up to 6) orthohydrogen molecules (j = 1), with the total number of molecules ranging from 4 to 40 at temperatures of 1.5, 3, and 4.5 K. Some energy parameters
(including the chemical potentials) and spatial characteristics of the clusters are found. At a temperature of 1.5 K, as the
total number N of molecules in the cluster increases, the chemical potential and the rotational energy of the clusters attain local minima
at the same geometrically determined values of N (the magic numbers). The ortho-molecules exhibit a larger probability (compared to the para-molecules) to reside in the central
region of the cluster and a smaller probability to be located near its surface. This effect is enhanced as the number of orthohydrogen
molecules in the cluster increases, the total number N of molecules grows, or the temperature is lowered. 相似文献
58.
A. A. Burenkov D. Yu. Akimov Yu. L. Grishkin A. G. Kovalenko V. N. Lebedenko V. N. Solovov V. N. Stekhanov F. Neves T. J. Sumner 《Physics of Atomic Nuclei》2009,72(4):653-661
It is experimentally shown that a single ionization electron can be detected by various xenon-based electroluminescent detectors with optical readout, such as a high-pressure cylindrical gas counter, a two-phase detector with gas amplification, and a two-phase detector with a plane-parallel and uniform electric field. The sensitivity of the detectors was 7, 18, and 15 photoelectrons respectively. The coordinate resolution of the two-phase detector for electrons resulting from field emission at the cathode was σ X,Y = 5.2 mm. 相似文献
59.
S. V. Akimov V. M. Duda E. F. Dudnik A. I. Kushnerev A. N. Tomchakov 《Physics of the Solid State》2006,48(6):1073-1076
Nineteen types of phase transitions in nonmagnetic crystals that exhibit only partial mixed ferroelectric-ferroelastic properties in the low-temperature phase are analyzed. A crystal-physical method is used to establish that all partial mixed ferroelectric ferroelastics are full ferroelastoelectrics and partial ferrobielastics except for the crystals undergoing the $\overline 4 3m \to 3$ phase transition, which results in the appearance of both full ferroelastoelectric and full ferrobielastic properties. The possible appearance of partial mixed ferroelectric-ferroelastic properties in perovskite-like crystals is discussed. 相似文献
60.
Aad G Abbott B Abdallah J Abdel Khalek S Abdelalim AA Abdesselam A Abdinov O Abi B Abolins M Abouzeid OS Abramowicz H Abreu H Acerbi E Acharya BS Adamczyk L Adams DL Addy TN Adelman J Aderholz M Adomeit S Adragna P Adye T Aefsky S Aguilar-Saavedra JA Aharrouche M Ahlen SP Ahles F Ahmad A Ahsan M Aielli G Akdogan T Akesson TP Akimoto G Akimov AV Akiyama A Alam MS Alam MA Albert J Albrand S Aleksa M Aleksandrov IN Alessandria F Alexa C Alexander G Alexandre G Alexopoulos T Alhroob M Aliev M 《Physical review letters》2012,108(11):111803
A search for the standard model Higgs boson is performed in the diphoton decay channel. The data used correspond to an integrated luminosity of 4.9 fb(-1) collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of √s=7 TeV. In the diphoton mass range 110-150 GeV, the largest excess with respect to the background-only hypothesis is observed at 126.5 GeV, with a local significance of 2.8 standard deviations. Taking the look-elsewhere effect into account in the range 110-150 GeV, this significance becomes 1.5 standard deviations. The standard model Higgs boson is excluded at 95% confidence level in the mass ranges of 113-115 GeV and 134.5-136 GeV. 相似文献