全文获取类型
收费全文 | 741篇 |
免费 | 32篇 |
国内免费 | 3篇 |
专业分类
化学 | 84篇 |
晶体学 | 15篇 |
力学 | 3篇 |
综合类 | 1篇 |
数学 | 16篇 |
物理学 | 657篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 12篇 |
2009年 | 82篇 |
2008年 | 121篇 |
2007年 | 80篇 |
2006年 | 65篇 |
2005年 | 33篇 |
2004年 | 26篇 |
2003年 | 17篇 |
2002年 | 75篇 |
2001年 | 37篇 |
2000年 | 24篇 |
1999年 | 25篇 |
1998年 | 25篇 |
1997年 | 3篇 |
1996年 | 9篇 |
1995年 | 19篇 |
1994年 | 22篇 |
1993年 | 10篇 |
1992年 | 16篇 |
1991年 | 18篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 1篇 |
排序方式: 共有776条查询结果,搜索用时 0 毫秒
91.
J. Giovinazzo B. Blank C. Borcea M. Chartier S. Czajkowski G. de France R. Grzywacz Z. Janas M. Lewitowicz F. de Oliveira Santos M. Pfützner M.S. Pravikoff J.C. Thomas 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):73-84
Decay studies of very neutron-deficient nuclei ranging from 39Ti to 49Ni have been performed during a projectile fragmentation experiment at the GANIL/LISE3 separator. For all nuclei studied in
this work, 39, 40Ti, 42, 43Cr, 46Mn, 45, 46, 47Fe and 49Ni, half-lives and decay spectra have been measured. In a few cases, γ coincidence measurements helped to successfully identify
the initial and final states of transitions. In these cases, partial decay scheme are proposed. For the most exotic isotopes,
39Ti, 42Cr, 45Fe and 49Ni, which are candidates for two-proton radioactivity from the ground state, no clear evidence of this process is seen in
our spectra and we conclude rather on a delayed particle decay.
Received: 26 July 2000 / Accepted: 20 December 2000 相似文献
92.
H. Norström K. Maex J. Vanhellemont G. Brijs W. Vandervorst U. Smith 《Applied Physics A: Materials Science & Processing》1990,51(6):459-466
The formation of (TixW1–x)Si2/(TixW1–x)N, by rapid thermal processing of TixW1–x on Si in an N2 ambient is investigated. An activation energy of 1.7 eV is obtained for silicide formation. A distinct snow-ploughing of As atoms is observed during silicide formation whereas the interfacial B concentration decreases with increasing silicide formation temperature. The diffusion barrier properties of the (TixW1–x)Si2/(TixWi1–x)N stack in contact with Al is investigated upon post-metal annealing. No interaction between the layers is found for temperatures as high as 475°C after 60 min. The improved thermal stability of the (TixW1–x)N layer in contact with Al is attributed to nitrogen blocking of the grain boundaries. 相似文献
93.
L-L. Andersson D. Rudolph J. Ekman C. Fahlander E. K. Johansson R. du Rietz C. J. Gross P. A. Hausladen D. C. Radford G. Hammond 《The European Physical Journal A - Hadrons and Nuclei》2006,30(2):381-390
The 61
30Zn31 isotope has been produced at the Oak Ridge National Laboratory in the fusion-evaporation reaction 40Ca(24Mg, 2pn)61Zn at 104MeV. The experimental set-up allowed γ-rays to be detected in the CLARION Ge detector array in coincidence with the
detection of recoiling nuclei in the focal plane at the end of the recoil mass spectrometer. This provides a unique identification
of γ-rays belonging to 61Zn. The excited states have been explored by means of recoil- γγ coincidences, and the resulting decay scheme comprises almost
70 transitions. The data reveal numerous non-yrast states and suggest a revised spin and parity assignment for a previously
observed superdeformed band. The resulting decay scheme is compared to predictions from different sets of large-scale shell
model calculations. 相似文献
94.
P. Indelicato S. Boucard E. Lindroth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,3(1):29-41
We report on a calculation of K, L and M inner-shell ionization energy in atoms with atomic numbers in the range . Many-body effects are evaluated for all n
=1, 2, and 3 hole states. Those include correlation and effects due to the auto-ionizing nature of the hole states (Auger shift). For
high Z we add recent corrected nuclear polarization, and several second-order vacuum polarization corrections. K and L ionization
energies are compared with experimental X-ray absorption edges measurements. Excellent agreement with rare gazes and metal
vapor measurements is found. We also compare our calculations with X-ray transition energies for all K and L lines that involve
K, L and M holes. Finally we use K X-ray lines to deduce an hydrogenlike 1
s Lamb shift for several heavy elements, with far better accuracy than has been obtained by direct measurements of hydrogenlike
ions.
Received: 25 February 1998 / Accepted: 31 March 1998 相似文献
95.
Hrant Yeritsyan Vachagan Harutiunian Volodia Gevorkyan Norair Grigoryan Eleonora Hakhverdyan Sergey Nikoghosyan Aram Sahakyan Rudolf Gevorgyan Hakob Sargisyan Yeghis Keheyan 《Central European Journal of Physics》2005,3(4):623-635
Infrared (IR) absorption and luminescence in chemically and radiation-modified natural Armenian Zeolite (clinoptilolite) samples
have been studied. The luminescence was studied in 390–450 nm and 620–710 nm wavelength bands, and the IR measurements were
carried out in the 400–5400 cm−1 range. It is shown that the luminescence intensity depends on the content of pure clinoptilolite in the samples and, probably
on the distribution of “passive” luminescence centers over Si and Al sites that became “active” under radiation or chemical
treatment. The samples of electron irradiated clinoptilolite have higher luminescence intensity than the chemically and thermally
treated ones. A decrease in the intensity of IR absorption bands at 3550 cm−1 and 3650 cm−1 was found after irradiation. 相似文献
96.
The electronic structure of hexagonal Gd3Co11B4 compound has been studied by X-ray photoemission spectroscopy (XPS) and ab initio self-consistent tight binding linear muffin tin orbital (TB LMTO) method. We have found a good agreement between the experimental XPS valence band spectra and theoretical LMTO calculations. Results showed that the Gd3Co11B4 compound is ferrimagnetic with the calculated total magnetic moment M=14.29 μB/f.u. The values of the magnetic moments on Co atoms strongly depend on the local environment. We have also compared the electronic structure and magnetic properties of Gd3Co11B4 compound with those of Nd3Co11B4 compound. 相似文献
97.
The effects of chemical heat treatments of a semi-anthracite char (AC) on textural properties and reactivity in air of the material are investigated. The starting char was first treated with a mixture of LiCl/KCl or LiCl/KCl/CaO at 743, 873 or 1173 K and the products obtained were then washed thoroughly with distilled water. A small fraction of these samples were treated with 10−3 M HCl solution. Valuable information on textural modifications produced in the material was derived from the adsorption isotherms for CO2 at 273 K. The reactivity tests were carried out at 808, 823 and 823 K. The microporosity developed and the reactivity in air increased in the partially demineralised products. The former effect was stronger for the LiCl/KCl/CaO-treated samples and the latter for a larger number of the LiCl/KCl-treated samples. 相似文献
98.
99.
Thin films of aluminium oxide have been deposited on glass, quartz, Si(100), steel, nickel, and aluminium by plasma-enhanced chemical vapour deposition (PECVD) using aluminium acetylacetonate (Al(acac)3) as precursor. The deposits are hard (up to 2370 HK) and show good adherence to the substrates. The influence of various experimental parameters on deposition rate, film composition and hardness has been studied. The bias turned out to be the most effective parameter.On leave from Beijing Solar Energy Research Institute, Beijing, P.R. China 相似文献
100.
D. Rudolph R. Hoischen M. Hellström S. Pietri Zs. Podolyák P. H. Regan A. B. Garnsworthy S. J. Steer F. Becker P. Bednarczyk L. Cáceres P. Doornenbal J. Gerl M. Górska J. Grebosz I. Kojouharov N. Kurz W. Prokopowicz H. Schaffner H. J. Wollersheim L. -L. Andersson L. Atanasova D. L. Balabanski M. A. Bentley A. Blazhev C. Brandau J. R. Brown C. Fahlander E. K. Johansson A. Jungclaus 《The European Physical Journal A - Hadrons and Nuclei》2008,36(2):131-138
The fragmentation of a 550MeV/u primary beam of 58Ni on a 9Be target has been used to measure time- and energy-correlated γ decays following the implantation of event-by-event discriminated
secondary fragments into a 9Be stopper plate. A new isomeric γ decay with T
1/2 = 14(
) ns and E
γ = 646.2(2) keV is observed and attributed to the decay of the yrast 3/2- state in 53
27Co26 . This short-lived isomeric state has been populated by means of nuclear reactions during the stopping process of the secondary
fragments. The experimental findings are discussed in the framework of large-scale spherical shell model calculations in conjunction
with isospin symmetry-breaking residual interactions for the A = 53 , T
z = ±1/2 mirror nuclei 53Co and 53Fe . 相似文献