全文获取类型
收费全文 | 2891篇 |
免费 | 49篇 |
国内免费 | 11篇 |
专业分类
化学 | 1857篇 |
晶体学 | 25篇 |
力学 | 59篇 |
数学 | 262篇 |
物理学 | 748篇 |
出版年
2019年 | 20篇 |
2016年 | 39篇 |
2015年 | 39篇 |
2014年 | 39篇 |
2013年 | 93篇 |
2012年 | 133篇 |
2011年 | 121篇 |
2010年 | 72篇 |
2009年 | 70篇 |
2008年 | 109篇 |
2007年 | 79篇 |
2006年 | 114篇 |
2005年 | 91篇 |
2004年 | 83篇 |
2003年 | 76篇 |
2002年 | 67篇 |
2001年 | 64篇 |
2000年 | 58篇 |
1999年 | 44篇 |
1998年 | 47篇 |
1997年 | 52篇 |
1996年 | 56篇 |
1995年 | 58篇 |
1994年 | 59篇 |
1993年 | 47篇 |
1992年 | 53篇 |
1991年 | 49篇 |
1990年 | 40篇 |
1989年 | 30篇 |
1988年 | 46篇 |
1987年 | 31篇 |
1986年 | 34篇 |
1985年 | 47篇 |
1984年 | 45篇 |
1983年 | 24篇 |
1982年 | 37篇 |
1981年 | 63篇 |
1980年 | 37篇 |
1979年 | 35篇 |
1978年 | 58篇 |
1977年 | 46篇 |
1976年 | 44篇 |
1975年 | 44篇 |
1974年 | 37篇 |
1973年 | 33篇 |
1972年 | 18篇 |
1970年 | 33篇 |
1967年 | 20篇 |
1966年 | 17篇 |
1965年 | 18篇 |
排序方式: 共有2951条查询结果,搜索用时 15 毫秒
41.
42.
The spin dynamics of muons interacting with acceptor impurity nuclei in silicon is investigated. Using values of electric field gradients obtained from ab-initio calculations, the field dependence of the longitudinal muon polarization is calculated for SiB and SiAl and compared to the contributions from paramagnetic bond-center muonium. 相似文献
43.
44.
45.
Anthony PL Arnold RG Band HR Borel H Bosted PE Breton V Cates GD Chupp TE Dietrich FS Dunne J Erbacher R Fellbaum J Fonvieille H Gearhart R Holmes R Hughes EW Johnson JR Kawall D Keppel C Kuhn SE Lombard-Nelsen RM Marroncle J Maruyama T Meyer W Meziani Z Middleton H Morgenstern J Newbury NR Petratos GG Pitthan R Prepost R Roblin Y Rock SE Rokni SH Shapiro G Smith T Souder PA Spengos M Staley F Stuart LM Szalata ZM Terrien Y Thompson AK White JL Woods M Xu J Young CC Zapalac G 《Physical review D: Particles and fields》1996,54(11):6620-6650
46.
Lung A Stuart LM Bosted PE Andivahis L Alster J Arnold RG Chang CC Dietrich FS Dodge WR Gearhart R Gomez J Griffioen KA Hicks RS Hyde-Wright CE Keppel C Kuhn SE Lichtenstadt J Miskimen RA Peterson GA Petratos GG Rock SE Rokni SH Sakumoto WK Spengos M Swartz K Szalata Z Tao LH 《Physical review letters》1993,70(6):718-721
47.
48.
U. Groß P. Dietrich G. Engler D. Prescher J. Schulze K. Lunkwitz A. Ferse 《Journal of fluorine chemistry》1982,20(1):33-52
The present work studies the changes in polymer structure and the mechanism of the decomposition of polytetrafluoroethylene resin (PTFE) exposed to high energy radiation (electron beam). Spectroscopic and kinetic observations are used to interpret the degradation process. For the first time the decomposition of PTFE has been carried out on a preparative scale and new results obtained by analysing the degradation products. The radiation-induced degradation of PTFE is accompanied by thermal degradation under certain irradiation conditions. This is due to an increase in temperature of the polymer caused by retardation of highly accelerated electrons (heat accumulation effect).The kinetics are discussed in terms of the reactions and recombination of radicals produced by high-energy radiation both in the polymer melt and the polymer surface. These are related to the overall rate of decomposition.The primary radicals formed by decomposition of PTFE in an inert atmosphere (N2, Ar) react to produce perfluorinated alkanes and alkenes. In the presence of reactive gases the decomposition fragments originated will react rapidly; e.g. if oxygen is present in the reactive area the radicals form perflourinated peroxyl and oxyl radicals which finally stabilize themselves by CC-scission to perfluorocarbon acid fluorides and carbonyldifluorides. 相似文献
49.
C. Meier M. Volkmer J. Lieschke M. Fink N. Böwering 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1994,30(2):183-187
Relative elastic differential cross sections for scattering of 1 keV electrons from CF3H, CF4, CF3Cl, CH3F and CH3Cl molecules were measured for momentum transfer from 3 Å?1 to 29 Å?1. The oscillatory residuals remaining after substraction of the atomic scattering and the molecular interference contributions calculated in the independent atom model are ascribed to the influence of intramolecular multiple scattering. The data reflect the dominant contributions of the CF3-group and show larger oscillations than obtained from triple scattering calculations according to the method of Liu and Bonham using the second Born approximation. 相似文献
50.
The quantitation of thiopental in human serum and plasma was investigated using high-performance capillary electrophoresis (HPCE) in a micellar configuration and the results were compared with reversed-phase high-performance liquid chromatography (HPLC). Thiopental and an internal standard (carbamazepine for HPCE and thiamylal for HPLC) were extracted from serum or plasma using pentane and a phosphate buffer (pH 6.4). HPCE analysis took place in a phosphate-borate buffer with 50 mM sodium dodecyl sulphate using an automated instrument and HPLC was performed with a C8 column and a mobile phase of phosphate buffer-acetonitrile (65:35, v/v). HPCE and HPLC data from 66 patient samples compared well based on linear regression analysis. However, estimates obtained with the inclusion of the internal standard were lower than those based on the sample peak only. This example allows the elucidation of the advantages of using HPCE as an assay methodology for the therapeutic monitoring of thiopental and other drugs. 相似文献