全文获取类型
收费全文 | 638793篇 |
免费 | 9471篇 |
国内免费 | 5905篇 |
专业分类
化学 | 319022篇 |
晶体学 | 8927篇 |
力学 | 34456篇 |
综合类 | 339篇 |
数学 | 92522篇 |
物理学 | 198903篇 |
出版年
2021年 | 6556篇 |
2020年 | 7131篇 |
2019年 | 7900篇 |
2018年 | 14377篇 |
2017年 | 14552篇 |
2016年 | 15851篇 |
2015年 | 8358篇 |
2014年 | 12883篇 |
2013年 | 26863篇 |
2012年 | 24334篇 |
2011年 | 32311篇 |
2010年 | 23000篇 |
2009年 | 22991篇 |
2008年 | 29277篇 |
2007年 | 30982篇 |
2006年 | 21173篇 |
2005年 | 21826篇 |
2004年 | 18880篇 |
2003年 | 17568篇 |
2002年 | 16507篇 |
2001年 | 16379篇 |
2000年 | 12832篇 |
1999年 | 9863篇 |
1998年 | 8630篇 |
1997年 | 8298篇 |
1996年 | 7922篇 |
1995年 | 7075篇 |
1994年 | 7101篇 |
1993年 | 6789篇 |
1992年 | 7060篇 |
1991年 | 7523篇 |
1990年 | 7237篇 |
1989年 | 7079篇 |
1988年 | 6838篇 |
1987年 | 6597篇 |
1986年 | 6342篇 |
1985年 | 7923篇 |
1984年 | 8256篇 |
1983年 | 6973篇 |
1982年 | 7244篇 |
1981年 | 6709篇 |
1980年 | 6381篇 |
1979年 | 6949篇 |
1978年 | 7188篇 |
1977年 | 7006篇 |
1976年 | 7063篇 |
1975年 | 6733篇 |
1974年 | 6559篇 |
1973年 | 6924篇 |
1972年 | 5108篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
A new approach to identify the independent amplitudes along with their partial wave multipole expansions, for photo-and electro-production
is suggested, which is generally applicable to mesons with arbitrary spin-parity. These amplitudes facilitate direct identification
of different resonance contributions.
相似文献
962.
963.
I. A. Anoshko V. S. Ermachenko L. E. Sandrigailo 《Journal of Applied Spectroscopy》2007,74(1):102-106
We present the results of a spectroscopic study of a nonequilibrium plasma in a Hall accelerator, in particular for such an
important parameter as the electron temperature. For the studied conditions, we used the semicoronal equilibrium model, which
relates the intensity ratios for two successive ionization steps for the same element.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 93–96, January–February, 2007. 相似文献
964.
We report on a new type of Fano effect, named as Andreev-Fano effect, in a hybrid normal-metal/supeeconductor (N/S) interferometer embedded with a quantum dot. Compared with the conventional Fano effect, AndreevFano effect has some new features related to the characteristics of Andreev reflection. In the Iinear response regime, the line shape is the square of the conventional Fano shape, while in the nonlinear transport, a sharp resonant structure is superposed on an expanded interference pattern, which is qualitatively different from the conventional Fano effect. The phase dependence of the hybrid N/S interferometer is also distinguished from those of all-N or all-S interferometers. 相似文献
965.
966.
967.
The synthesis of polyaniline via the oxidation of aniline with ammonium bisulfate in water and formic acid was monitored potentiometrically by following the yield and changes in the electric conductivity of the polymer. Three basic stages of the process were determined, including the buildup of oligomeric quinone imines, chain propagation via aniline addition of quinone imine groups, and postpolymerization. The oligomeric intermediate products, substituted quinone imines, were isolated. On the basis of IR and NMR data, the presence of tri-and tetrasubstituted aromatic groups and phenazine structural units in the polyaniline chain was revealed. 相似文献
968.
The phase transitions and phase state of hydroxypropylcellulose mixtures with ethanol and acetic acid under static conditions and in the shear field have been studied by the turbidity-point method and polarization microscopy with the use of a polarization-photoelectric setup and a modified plastoviscometer. The deformation of solutions leads to a decrease in the temperature of mesomorphic phase formation and to a change in the type of liquid crystals from cholesteric to nematic. 相似文献
969.
S. V. Valueva L. N. Borovikova V. V. Koreneva Ya. I. Nazarkina A. I. Kipper V. V. Kopeikin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(7):1170-1173
Nanostructures formed during the reduction of ionic selenium in the selenite-ascorbate redox system in an aqueous solution of bovine serum albumin (BSA) were studied using static and dynamic light scattering and flow birefringence. It was established that this process results in the formation of stable aggregates of selenium nanoparticles that adsorb BSA molecules. It was found that highly-ordered superhigh-molecular-weight spherical nanostructures with high density and unique morphology are formed. Experiments with a cell culture of promyelocytic leukemia HL-60 showed that BSA adsorbed on selenium nanoparticles can inhibit the growth of tumor cells and deactivate free radicals with an efficiency comparable with that of sodium selenite. 相似文献
970.
Jiguo Yu Qiuju Bian Guizhen Liu Na Wang 《Journal of Applied Mathematics and Computing》2007,25(1-2):283-291
A simple graphG is said to be fractionaln-factor-critical if after deleting anyn vertices the remaining subgraph still has a fractional perfect matching. For fractionaln-factor-criticality, in this paper, one necessary and sufficient condition, and three sufficient conditions related to maximum matching, complete closure are given. 相似文献