全文获取类型
收费全文 | 630095篇 |
免费 | 5065篇 |
国内免费 | 1634篇 |
专业分类
化学 | 319310篇 |
晶体学 | 9241篇 |
力学 | 32044篇 |
综合类 | 27篇 |
数学 | 83027篇 |
物理学 | 193145篇 |
出版年
2021年 | 5833篇 |
2020年 | 6288篇 |
2019年 | 7175篇 |
2018年 | 9687篇 |
2017年 | 9817篇 |
2016年 | 13578篇 |
2015年 | 7286篇 |
2014年 | 12338篇 |
2013年 | 27945篇 |
2012年 | 21635篇 |
2011年 | 25755篇 |
2010年 | 19420篇 |
2009年 | 19377篇 |
2008年 | 24373篇 |
2007年 | 24129篇 |
2006年 | 21906篇 |
2005年 | 19566篇 |
2004年 | 18340篇 |
2003年 | 16520篇 |
2002年 | 16344篇 |
2001年 | 17519篇 |
2000年 | 13473篇 |
1999年 | 10444篇 |
1998年 | 8980篇 |
1997年 | 8902篇 |
1996年 | 8336篇 |
1995年 | 7471篇 |
1994年 | 7550篇 |
1993年 | 7273篇 |
1992年 | 7835篇 |
1991年 | 8230篇 |
1990年 | 7948篇 |
1989年 | 7860篇 |
1988年 | 7651篇 |
1987年 | 7388篇 |
1986年 | 7112篇 |
1985年 | 9115篇 |
1984年 | 9526篇 |
1983年 | 7963篇 |
1982年 | 8191篇 |
1981年 | 7751篇 |
1980年 | 7325篇 |
1979年 | 7960篇 |
1978年 | 8191篇 |
1977年 | 8166篇 |
1976年 | 8145篇 |
1975年 | 7778篇 |
1974年 | 7573篇 |
1973年 | 7932篇 |
1972年 | 5836篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
161.
V. A. Alekseev 《Optics and Spectroscopy》2004,96(4):492-496
The absorption spectra of Xe + CF4 and Kr + CF4 mixtures in the vacuum ultraviolet region are presented. A considerable broadening of the short-wavelength wings of the atomic absorption lines is explained by a repulsive character of the Rg*-CF4 interaction potential. This repulsive character is also considered to be the most probable reason for the anomalously small cross sections of the quenching of electronically excited atoms of rare gases by CF4 molecules. The influence of CF4 on the emission rate of the trapped resonance radiation of Xe from the cell is discussed. 相似文献
162.
M. A. Nikitina 《Russian Physics Journal》2003,46(3):296-304
The h
2-persistent multiple-access communication networks with discrete and continuous strategy of control of conflict messages are investigated. 相似文献
163.
164.
X-ray diffraction patterns of nanocrystalline Fe-Cu-Nb-Si-B (FINEMET) alloys reveal that bcc α-Fe/α-FeSi crystallites with
the average grain size of 20(5) nm are dispersed in amorphous matrix. Enhanced electron—electron interaction (EEI) and quantum
interference (QI) effects as well as electron-magnon (and/or electron-spin fluctuation) scattering turn out to be the main
mechanisms that govern the temperature dependence of resistivity. Of all the inelastic scattering processes, inelastic electron-phonon
scattering is the most effective mechanism to destroy phase coherence of electron wave functions. The diffusion constant,
density of states at the Fermi level and the inelastic scattering time have been estimated, for the first time, for the alloys
in question
Article presented at the International Symposium on Advances in Superconductivity and Magnetism: Materials, Mechanisms and
Devices, ASMM2D-2001, 25–28 September 2001, Mangalore, India. 相似文献
165.
Jeroen J. L. M. Cornelissen W. Sander Graswinckel Alan E. Rowan Nico A. J. M. Sommerdijk Roeland J. M. Nolte 《Journal of polymer science. Part A, Polymer chemistry》2003,41(11):1725-1736
The conformational properties of polymers derived from isocyanodipeptides have been investigated with a combination of model calculations, X‐ray diffraction, and circular dichroism spectroscopy. Depending on the configuration of the side chains, defined arrays of hydrogen bonds along the polymeric backbone are formed. This leads to a well‐defined conformation as, for example, expressed in the formation of lyotropic liquid‐crystalline phases and increased helical stability. Upon the disruption of the hydrogen bonds by a strong acid, a less well‐defined macromolecular conformation is observed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1725–1736, 2003 相似文献
166.
A. Khrennikov 《Annalen der Physik》2003,12(10):575-585
We study the probabilistic consequences of the choice of the basic number field in the quantum formalism. We demonstrate that by choosing a number field for a linear space representation of quantum model it is possible to describe various interference phenomena. We analyse interference of probabilistic alternatives induced by real, complex, hyperbolic (Clifford) and p‐adic representations. 相似文献
167.
Hellweg T. Schemmel S. Rother G. Brlet A. Eckerlebe H. Findenegg G.H. 《The European physical journal. E, Soft matter》2003,12(1):1-4
The European Physical Journal E - The temperature-induced microphase separation of the binary liquid system iso-butyric acid+heavy water (iBA + D2O) in a mesoporous silica glass (CPG-10-75) of... 相似文献
168.
169.
M Lepère R Gobeille V.Malathy Devi M.A.H Smith B Aoaeh A.W Mantz 《Journal of Molecular Spectroscopy》2004,224(1):7-12
We have analyzed the methyl fluoride RQ(J,0)Q branch lines located near 1475 cm−1 using a simultaneous multi-spectrum fitting technique. In this analysis we have used previously recorded diode-laser data in which we collected many data points covering only one or two Q branch lines in a particular run. The analysis consists of simultaneously fitting 57 spectra collected with numerous pressure and path length conditions for all absorption lines. The data are concatenated to create one continuous spectrum of the Q branch. We have determined the intensity and self-broadened widths at 296 K for 23 RQ(J,0) lines. 相似文献
170.
We investigate the dynamics of the Λ system driven by two resonant laser fields in presence of dissipation for coupling strengths where the rotating‐wave approximation starts to break down. This regime is characterised by Rabi frequencies being approximately equal or smaller than the field frequencies. A systematic procedure to obtain an expansion for the solution of the Bloch evolution equations of the system is presented. The lowest contribution results to be the well‐known rotating‐wave approximation. The method is based on a semi‐classical treatment of the problem, and its predictions are interpreted fully quantum mechanically. The theory is illustrated by a detailed study of the disappearance of coherent population trapping as the intensities of the fields increase. 相似文献