全文获取类型
收费全文 | 390204篇 |
免费 | 3767篇 |
国内免费 | 1094篇 |
专业分类
化学 | 213930篇 |
晶体学 | 6417篇 |
力学 | 15623篇 |
综合类 | 17篇 |
数学 | 41451篇 |
物理学 | 117627篇 |
出版年
2020年 | 3430篇 |
2019年 | 3853篇 |
2018年 | 5011篇 |
2017年 | 5032篇 |
2016年 | 7177篇 |
2015年 | 4282篇 |
2014年 | 6862篇 |
2013年 | 17387篇 |
2012年 | 12588篇 |
2011年 | 15333篇 |
2010年 | 11018篇 |
2009年 | 10891篇 |
2008年 | 14287篇 |
2007年 | 14248篇 |
2006年 | 13277篇 |
2005年 | 12051篇 |
2004年 | 10845篇 |
2003年 | 9976篇 |
2002年 | 9640篇 |
2001年 | 11126篇 |
2000年 | 8587篇 |
1999年 | 6550篇 |
1998年 | 5390篇 |
1997年 | 5408篇 |
1996年 | 5073篇 |
1995年 | 4471篇 |
1994年 | 4447篇 |
1993年 | 4325篇 |
1992年 | 5056篇 |
1991年 | 5030篇 |
1990年 | 4880篇 |
1989年 | 4914篇 |
1988年 | 4851篇 |
1987年 | 4835篇 |
1986年 | 4613篇 |
1985年 | 5965篇 |
1984年 | 6126篇 |
1983年 | 4855篇 |
1982年 | 5191篇 |
1981年 | 5129篇 |
1980年 | 4757篇 |
1979年 | 5267篇 |
1978年 | 5376篇 |
1977年 | 5477篇 |
1976年 | 5341篇 |
1975年 | 4931篇 |
1974年 | 4872篇 |
1973年 | 4952篇 |
1972年 | 3369篇 |
1967年 | 3278篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
A. E. Dorokhov 《Czechoslovak Journal of Physics》2002,52(3):C79-C90
Nonperturbative nolocal structure of QCD vacuum is well described by instanton model. Specific helicity and flavor structure of zero modes of quarks, in instanton field allows simultaneously to explain some important features of low-and high-energy hadron phenomemology. The basic characteristics of hadron spectrum, partonic sum rules, heavyquark potential etc within the instanton liquid model are briefly discussed. 相似文献
92.
The dependence of the beam propagation factor (M
2 parameter) with the absorbed pump power in the case of monolithic microchip laser under face-cooled configuration is extensively
studied. Our investigations show that the M
2 parameter is related to the absorbed pump power through two parameters (α and β) whose values depend on the laser material properties and laser configuration. We have shown that one parameter arises due
to the oscillation of higher order modes in the microchip cavity and the other parameter accounts for the spherical aberration
associated with the thermal lens induced by the pump beam. Such dependency of M
2 parameter with the absorbed pump power is experimentally verified for a face-cooled monolithic microchip laser based on Nd3+ -doped GdVO4 crystal and the values of α and β parameters were estimated from the experimentally measured data points. 相似文献
93.
The microhardness and content of carbon in electroplated gold coatings were studied as influenced by the operation time of citrate and citrate-phosphate gold-plating electrolytes. Such physicomechanical properties as porosity, microhardness, internal stress, plasticity, and microstructure of electroless-plated and electroplated nickel coatings were studied and analyzed. 相似文献
94.
D. V. Vyalykh A. M. Shikin G. V. Prudnikova A. Yu. Grigor’ev A. G. Starodubov V. K. Adamchuk 《Physics of the Solid State》2002,44(1):164-170
This paper reports on the first experimental observation of quantum-well states and sp-type resonances in thin single-crystal gold, silver, and copper layers formed on single-crystal W(110) surfaces, which result from spatial localization of Bloch-type electronic wave functions in a quantum well with potential barriers at the vacuum/metal and metal/W(110) interfaces. The quantization of the valence-band electronic structure in Au/W(110), Ag/W(110), and Cu/W(110) systems was studied experimentally using angle-resolved photoelectron spectroscopy. 相似文献
95.
The problem of the vector and axial-vector dominance of weak interactions within the framework of the quark model of superconductivity type is discussed. 相似文献
96.
97.
98.
99.
100.
A convenient method is proposed for the synthesis of all the individual methyl ethers of methyl 2-acetamido-2-deoxy-α-D-glucopyranoside based on the partial methylation of 2-acetamido-2-deoxy-α-D-glucopyranoside with dimethyl sulfate in an alkaline medium followed by preparative liquid column chromatography on silica gel of the resulting mixture of methyl ethers. 相似文献