全文获取类型
收费全文 | 195篇 |
免费 | 10篇 |
专业分类
化学 | 126篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 23篇 |
物理学 | 52篇 |
出版年
2023年 | 2篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 16篇 |
2012年 | 9篇 |
2011年 | 18篇 |
2010年 | 12篇 |
2009年 | 2篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 3篇 |
1969年 | 1篇 |
1937年 | 1篇 |
1934年 | 1篇 |
1913年 | 1篇 |
1912年 | 1篇 |
1911年 | 1篇 |
排序方式: 共有205条查询结果,搜索用时 234 毫秒
41.
F. Bečvář I. Novotný I. Procházka D. Rafaja J. Kern 《Applied Physics A: Materials Science & Processing》1995,61(3):335-337
The neutron-irradiation effects on C60 fullerite powder were studied by positron lifetime spectroscopy. Below 0.5 ns, a single lifetime of 382±1 ps was found for the unirradiated annealed sample and two components were resolved after neutron irradiation with a dose of 2×1016 n/cm2. Possible origins of these components are briefly discussed.Paper presented at the 132nd WE-Heraeus-Seminar on Positron Studies of Semiconductor Defects, Halle, Germany, 29 August to 2 September 1994 相似文献
42.
V. Cojocaru C. Be§liu C. A. Manea 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(3):897-908
By means of nuclear analyses the concentrations of Au, Ag, Cu, Ir, Os, Pt, Co and Hg were measured in the 12 artifacts of the gold hoard discovered in 1837 at Pietroasa, Buzäu county in Romania. The concentrations of the first four elements were used to compare different stylistic groups assumed by historians. Comparisons with gold nuggets from the old Dacian territory and gold Roman imperial coins were also made. A good agreement was found with the oldest hypothesis which considers that the hoard is represented by three styles appropriated mainly by the Goths. 相似文献
43.
Maria Be?towska-Brzezinska Teresa ?uczakB?a?ej Gierczyk Krystian EitnerBogumil Brzezinski Rados?aw PankiewiczGrzegorz Schroeder 《Journal of Molecular Structure》2002,607(1):77-86
The complex formation of lithium and sodium ions with silicon podand solvents: phenyl-tris(1,4-dioxapentyl) silane (PhSi23) and ethyl-tris(1,4-dioxapentyl) silane (EtSi23) has been studied by FTIR, 1H-, 13C-, 7Li- and 23Na NMR. The far FTIR spectra show that the Li+ cations fluctuate very fast whereas Na+ cations are still localised between the oxygen atoms of the oxaalkyl chains. The 7Li NMR spectra prove that one Li+ cation can be coordinated not only by one but also two silicon podand molecules. The concentration dependence of the molar conductivity of LiClO4 in the podand solvents indicates charge transfer between ion clusters. 相似文献
44.
The complexation of p-tert-butylphenyl p-tert-butylbenzoate and N-(p-tert-butylphenyl)-p-tert-butylbenzamide with a β-cyclodextrin derivative formed by two cyclodextrin units linked by a disulfide bridge on one of the
C6 atoms has been studied by computational methods. The better amide solubility and the better internal interactions of the
ester complex explain the experimentally observed better association constant for the ester. The free-energy perturbation
methodology and molecular mechanics/Poisson–Boltzmann surface area analysis have been used to explain the problem and to compare
the results.
Received: 14 April 2002 / Accepted: 11 August 2002 / Published online: 4 November 2002
Acknowledgements. The Kollman group at the University of California San Francisco is gratefully acknowledged for support and encouragement
throughout all this study. The authors thank UAB for inland and outland fellowships to I.B.. Financial support was obtained
from grant no. PPQ2000-0369 from the “Ministerio de Ciencia y Tecnologia” (Spain). Intensive computations were performed either
with the computers of the Kollman group or with those of CESCA-C4 (Catalonia, Spain).
Correspondence to: C. Jaime e-mail: carlos.jaime@uab.es 相似文献
45.
Conductivity data of sodium chloride in binary mixtures of water and 1,4-dioxanefrom 5 to 35°C were measured, covering an electrolyte concentration range upto the limit of solubility in the solvent mixtures and up to 5 mol-dm–3 inpure water. Data analysis is based on the mean spherical approximation (MSA).Comparison is made with the data representation by the empirical Casteel-Amisequation. The association constants of the MSA are compared with those fromchemical model calculations at low concentrations (lcCM). 相似文献
46.
47.
In this study we consider a model of wet pressing of paper. We use the techniques and results from the first part of this
paper, where a simplified model is studied in details. The model is, using suitable transformation, rewritten in the standard
parabolic-hyperbolic form. Numerical solution for typical example is given and the effects of plastic deformations of paper
are investigated. Finally, the model is employed to adres the problem of choosing an optimal pressing regime. 相似文献
48.
49.
50.
Corrigendum: Composite Aromatic Boxes for Enzymatic Transformations of Quaternary Ammonium Substrates 下载免费PDF全文