全文获取类型
收费全文 | 15646篇 |
免费 | 640篇 |
国内免费 | 62篇 |
专业分类
化学 | 10811篇 |
晶体学 | 134篇 |
力学 | 412篇 |
数学 | 2269篇 |
物理学 | 2722篇 |
出版年
2023年 | 105篇 |
2022年 | 158篇 |
2021年 | 227篇 |
2020年 | 343篇 |
2019年 | 339篇 |
2018年 | 170篇 |
2017年 | 193篇 |
2016年 | 505篇 |
2015年 | 542篇 |
2014年 | 557篇 |
2013年 | 771篇 |
2012年 | 1045篇 |
2011年 | 1095篇 |
2010年 | 674篇 |
2009年 | 598篇 |
2008年 | 870篇 |
2007年 | 823篇 |
2006年 | 783篇 |
2005年 | 741篇 |
2004年 | 608篇 |
2003年 | 507篇 |
2002年 | 482篇 |
2001年 | 254篇 |
2000年 | 240篇 |
1999年 | 196篇 |
1998年 | 197篇 |
1997年 | 194篇 |
1996年 | 180篇 |
1995年 | 145篇 |
1994年 | 133篇 |
1993年 | 154篇 |
1992年 | 123篇 |
1991年 | 113篇 |
1990年 | 103篇 |
1989年 | 124篇 |
1988年 | 110篇 |
1987年 | 91篇 |
1986年 | 90篇 |
1985年 | 100篇 |
1984年 | 76篇 |
1983年 | 95篇 |
1982年 | 85篇 |
1981年 | 117篇 |
1980年 | 86篇 |
1979年 | 100篇 |
1978年 | 104篇 |
1977年 | 87篇 |
1976年 | 94篇 |
1975年 | 70篇 |
1973年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Stevenson NR Schubank RB Shin YM Amaudruz P Delheij PP Healey DC Jennings BK Ottewell DF Sheffer G Smith GR Wait GD Brack JT Feltham A Hanna M Johnson RR Rozon FM Sossi V Vetterli D Weber P Grion N Rui R Kohler M Ristinen RA Mathie EL Tacik R Yeomans M Gossett CA Wagner GJ 《Physical review letters》1990,65(16):1987-1990
43.
H. v. Brandis F. E. Wagner J. A. Sawicki K. Marcinkowska J. H. Rolston 《Hyperfine Interactions》1990,57(1-4):2127-2131
The state of iridium on Pt?Ir catalysts prepared by impregnation of amorphous silica with H2IrCl6 and H2PtCl6 was studied by193Ir Mössbauer spectroscopy after different steps of preparation. The Ir is adsorbed in its trivalent state, presumably as [IrCl6]3?. Calcination in air at 450°C converts this to IrO2. The metallic clusters formed by subsequent reduction in H2 at 200°C show a strong tendency towards segregation of Ir and Pt and re-oxidize partially when exposed to air at ambient temperature. In both respects the behaviour is similar to that of samples prepared by co-exchange from [Ir(NH3)5Cl]Cl2 and Pt(NH3)4Cl2. H2O. 相似文献
44.
45.
Joel L. Lebowitz Christian Maes Eugene R. Speer 《Journal of statistical physics》1990,59(1-2):117-170
We investigate the behavior of discrete-time probabilistic cellular automata (PCA), which are Markov processes on spin configurations on ad-dimensional lattice, from a rigorous statistical mechanics point of view. In particular, we exploit, whenever possible, the correspondence between stationary measures on the space-time histories of PCAs on
d
and translation-invariant Gibbs states for a related Hamiltonian on (
d+1). This leads to a simple large-deviation formula for the space-time histories of the PCA and a proof that in a high-temperature regime the stationary states of the PCA are Gibbsian. We also obtain results about entropy, fluctuations, and correlation inequalities, and demonstrate uniqueness of the invariant state and exponential decay of correlations in a high-noise regime. We discuss phase transitions in the low-noise (or low-temperature) regime and review Toom's proof of nonergodicity of a certain class of PCAs. 相似文献
46.
47.
48.
49.
50.
S. Patzer N.L. Arthur P. Potzinger H.Gg. Wagner 《Journal of photochemistry and photobiology. A, Chemistry》1997,110(3):2543-227
The photolysis of Me6Si2 at 206 nm results in two main decomposition processes: simple Si---Si bond breaking with a quantum yield of Φ = 0.21 ± 0.03, and Me3SiH elimination with the concomitant formation of Me2SiCH2 with Φ = 0.18 ± 0.01. There is also a minor decomposition channel with a very small quantum yield, Φ = (5.6 ± 0.2) × 10−3, which results in the formation of Me4Si and Me2Si. The main fate of the excited Me6Si2 molecule produced during photolysis is stabilization by collisional deactivation. The end products observed indicate that the reaction pathways followed by the main intermediates, Me3Si and Me2SiCH2, are the same as those found in the photolysis of Me4Si (Ahmed et al., J. Photochem. Photobiol. A: Chem. 86 (1995) 33). 相似文献