全文获取类型
收费全文 | 720篇 |
免费 | 12篇 |
专业分类
化学 | 396篇 |
晶体学 | 8篇 |
力学 | 13篇 |
数学 | 95篇 |
物理学 | 220篇 |
出版年
2021年 | 5篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 10篇 |
2013年 | 21篇 |
2012年 | 29篇 |
2011年 | 27篇 |
2010年 | 15篇 |
2009年 | 18篇 |
2008年 | 32篇 |
2007年 | 29篇 |
2006年 | 21篇 |
2005年 | 35篇 |
2004年 | 16篇 |
2003年 | 16篇 |
2002年 | 15篇 |
2001年 | 14篇 |
2000年 | 21篇 |
1999年 | 15篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 19篇 |
1986年 | 7篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 12篇 |
1981年 | 13篇 |
1979年 | 16篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1976年 | 13篇 |
1975年 | 9篇 |
1973年 | 7篇 |
1972年 | 4篇 |
1970年 | 7篇 |
1969年 | 5篇 |
1967年 | 8篇 |
1943年 | 4篇 |
1889年 | 4篇 |
1888年 | 4篇 |
排序方式: 共有732条查询结果,搜索用时 31 毫秒
121.
J. Kehrle V.I. Zdravkov G. Obermeier J. Garcia‐Garcia A. Ullrich C. Müller R. Morari A.S. Sidorenko S. Horn L.R. Tagirov R. Tidecks 《Annalen der Physik》2012,524(1):37-47
Ferromagnet/Superconductor/Ferromagnet (F/S/F) trilayers, in which the establishing of a Fulde‐Ferrell Larkin‐Ovchinnikov (FFLO) like state leads to interference effects of the superconducting pairing wave function, form the core of the superconducting spin valve. The realization of strong critical temperature oscillations in such trilayers, as a function of the ferromagnetic layer thicknesses or, even more efficient, reentrant superconductivity, are the key condition to obtain a large spin valve effect, i.e. a large shift in the critical temperature. Both phenomena have been realized experimentally in the Cu41Ni59/Nb/Cu41Ni59 trilayers investigated in the present work. 相似文献
122.
123.
124.
Bilge Eren Erdal Eren Murat Guney Yan-Ching Jean J. David Van Horn 《Journal of polymer science. Part A, Polymer chemistry》2020,58(4):589-598
Polyvinylidene fluoride (PVDF) membranes were prepared via the phase inversion method from casting solutions containing PVDF, dimethylformamide (DMF), and polyvinylpyrrolidone (PVP) as pore former. PVP was used in the casting solution in a range of 0–5 wt % and extracted. The effect on membranes of using PVP in the casting process was analyzed by X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, viscosity, and water permeability techniques. With an increase of PVP from 0 to 5 wt %, the PVDF casting solution viscosities increased from 858 to 1148 cP; the resulting PVDF membrane thickness increased; and the crystallinity of PVDF membranes decreased from 40.0 to 33.3%, which indicates that the addition of PVP inhibits the degree of crystallization in the PVDF membranes. SEM results revealed the shape and size of macropores in the membranes; these macropores changed after PVP addition to the casting solutions. The impact of structural changes on free-volume properties was evaluated using positron annihilation lifetime spectroscopy (PALS) studies. PALS analysis indicated no effect on the average radius (~3.4 Å) of membrane free-volume holes from the addition of PVP to the casting solution. However, the percentage of o-Ps pick-off annihilation intensity, I3, increased from 1.7 to 5.1% with increased PVP content. Further, increasing the PVP content from 0.5 to 5% resulted in an increased final pure water permeability flux. For instance, the 210 min flux for a 14% PVDF + 0.5% PVP membrane was found to be 3.3 times greater than a control membrane having the same PVDF concentration. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 589–598 相似文献
125.
126.
127.
128.
129.
130.