全文获取类型
收费全文 | 631篇 |
免费 | 15篇 |
国内免费 | 6篇 |
专业分类
化学 | 374篇 |
晶体学 | 6篇 |
力学 | 19篇 |
数学 | 73篇 |
物理学 | 180篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2019年 | 5篇 |
2017年 | 8篇 |
2016年 | 16篇 |
2015年 | 7篇 |
2014年 | 15篇 |
2013年 | 38篇 |
2012年 | 39篇 |
2011年 | 40篇 |
2010年 | 14篇 |
2009年 | 17篇 |
2008年 | 41篇 |
2007年 | 28篇 |
2006年 | 31篇 |
2005年 | 27篇 |
2004年 | 24篇 |
2003年 | 23篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 13篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 12篇 |
1979年 | 3篇 |
1978年 | 9篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 8篇 |
1970年 | 4篇 |
1969年 | 4篇 |
排序方式: 共有652条查询结果,搜索用时 562 毫秒
81.
Abstract High—pressure crystal structure studies have been performed on Sm up to 100 GPa using synchrotron x-radiation and a diamond anvil cell. The structural sequence Sm-dhcp-fcc-dist.fcc has been confirmed. There is no evidence of any volume collapse. The bulk modulus and its pressure derivative have been determined (B0 = 30.7 GPa, B0’ = 2.5). 相似文献
82.
The VF3-type compounds MF3 with M = Fe and Ga have been studied by high-pressure energy-dispersive X-ray diffraction. The compression mechanism was found to be highly anisotropic for both compounds, with the c-axis showing little pressure dependence. The volume reduction is mainly achieved through coupled rotations of the MF6 octahedra around the c-axis, which reduces the length of the a-axis. The compression mechanism of both compounds is reasonably well described in terms of deformation of an 8/3/c2 sphere-packing model up to the pressures where the fluorine atoms become hexagonally close-packed. It is proposed that both compounds enter a phase with the fluorine atom arranged in a “super-dense” sphere packing at higher pressures. The zero pressure bulk modulus of FeF3 and GaF3 was determined as 12(2) and 37(3) GPa, respectively, and a scaling relation between the zero pressure bulk modulus and unit cell volumes was found for TiF3, CrF3, FeF3 and GaF3. 相似文献
83.
Abstract The high-pressure crystal structures of the compounds UX, where X = N, P, As and Sb, have been studied using X-ray diffraction in the pressure range up to about 60 GPa Rhornbohedral distortions are observed for UN and Up above 29 GPa and lO GPa, respectively. In Up a further transformation to an orthorhombic phase occurs at 28 GPa. UAs and USb transform to the CsCl structure at 20 GPa and 9 GPa, respectively. The latter transformations show a considerable hysteresis when the pressure is released. The scaling behaviour of the bulk modulus has been studied. It is confirmed that a log-log plot of bulk modulus versus specific volume for the cubic phases gives a straight line with a slope near ? 5/3. 相似文献
84.
This is a survey on geometric constructions in multifractal analysis of measures. We show that the multifractal formalism introduced by Olsen [Ol11] and Peyriére [Pey] leads to a multifractal geometry for product measures, for slices of measures (i.e. intersections of measures with lower dimensional subspaces), and for general intersections of measures, which is analogous to the fractal geometry for product sets, for slices of sets (i.e. intersections of sets with lower dimensional subspaces), and for general intersections of sets, respectively. 相似文献
85.
R. Baur A. Breskin R. Chechik A. Drees C. Jacob U. Faschingbauer P. Fischer Z. Fraenkel E. Gatti P. Glässel Th. Günzel C. P. de los Heros F. Hess D. Irmscher B. Lenkeit L. H. Olsen Y. Panebrattsev A. Pfeiffer I. Ravinovich P. Rehak A. Schön J. Schukraft J. Schukraft M. Sampietro A. Shor H. J. Specht V. Steiner S. Tapprogge G. Tel-Zur I. Tserruya Th. Ullrich J. P. Wurm 《Zeitschrift fur Physik C Particles and Fields》1997,74(4):593-594
86.
Four equidistant peaks are observed below the Kα1,2 line in the X-ray spectra of Na, Al, Si, SiO2, Ca, Sc and Ti, produced by oxygen bombardment. With much weaker intensity, these lines are also seen in proton excitation. The lines are interpreted to be due to the excitation of one or more volume plasmons in the target material by the Kα1,2 X-ray decay. 相似文献
87.
Recently gas jet targets have been used for the study of small momentum transfer p-p and p-d elastic and inelastic scattering. In these experiments, which were performed at Serpukhov in the USSR and at the Fermilab in the USA, the gas jet is introduced in the main ring of the accelerator. We review the techniques associated with these measurements and summarize the published results which cover 4-momentum transfers 0.001< |t|< 0.12 (GeV/c)?2 and incident energies 8<E< 400 GeV. Elastic scattering data have yielded precise values for the slope of the nuclear scattering amplitude and for the ratio of the real to imaginary part as a function of energy. The implications of these data on the understanding of high energy hadronic interactions are discussed in some detail. We also present and discuss information on the diffractive dissociation of the proton to low mass states, obtained from inelastic scattering using the gas jet target. 相似文献
88.
Douglas A. Olsen A. Jean Osteraas 《Journal of polymer science. Part A, Polymer chemistry》1969,7(7):1921-1926
Previous work has shown that atomic sulfur irreversibility modifies polyethylene, presumably through an insertion reaction into carbon—hydrogen bonds with formation of surface thiol groups. The thiol groups were then oxidized to sulfonic acid surface groups, which were further reacted chemically as shown by wettability measurements. In this work the thiol group was bypassed and the surface sulfonic acid groups were obtained by exposing the polyethylene surface directly to fuming sulfuric acid. The sulfonic acid groups were reacted further. Critical surface tension values identical with those in the previous work with atomic sulfur were obtained, thus substantiating the previous work. 相似文献
89.
J. L. Olsen 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1958,9(3):293-294
Ohne Zusammenfassung 相似文献
90.