全文获取类型
收费全文 | 1064篇 |
免费 | 17篇 |
专业分类
化学 | 807篇 |
晶体学 | 11篇 |
力学 | 9篇 |
数学 | 56篇 |
物理学 | 198篇 |
出版年
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 33篇 |
2020年 | 25篇 |
2019年 | 33篇 |
2018年 | 47篇 |
2017年 | 45篇 |
2016年 | 25篇 |
2015年 | 28篇 |
2014年 | 32篇 |
2013年 | 74篇 |
2012年 | 35篇 |
2011年 | 58篇 |
2010年 | 49篇 |
2009年 | 45篇 |
2008年 | 51篇 |
2007年 | 62篇 |
2006年 | 50篇 |
2005年 | 42篇 |
2004年 | 43篇 |
2003年 | 29篇 |
2002年 | 33篇 |
2001年 | 22篇 |
2000年 | 10篇 |
1999年 | 14篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1981年 | 4篇 |
1980年 | 10篇 |
1979年 | 5篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1972年 | 6篇 |
1970年 | 5篇 |
1969年 | 4篇 |
1967年 | 4篇 |
1962年 | 4篇 |
排序方式: 共有1081条查询结果,搜索用时 296 毫秒
991.
We investigate the temperature dependence of the spin-spin dynamical autocorrelation function of the Ising spin glass Fe0.05TiS2 through field dependent muon-spin lattice relaxation measurements. We successfully analyze the results using the Ogielski function, namely, t(-x)exp((-[t/tau](y)) as employed in numerical simulations. The experimental estimates of x, y, and tau are compared with those from simulations. Our major finding is that in this system the correlation function changes its nature from Ogielski to a form indistinguishable from pure stretched exponential upon cooling close to T(g), indicating a dynamical crossover. 相似文献
992.
993.
994.
995.
S. N. Shurov L. I. Livantsova E. Yu. Pavlova G. S. Zaitseva Yu. S. Andreichikov O. N. Kolesnikova V. G. Baklykov 《Chemistry of Heterocyclic Compounds》1991,27(11):1267-1267
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, p. 1567, November, 1991. 相似文献
996.
997.
Pavlova S. N. Sazonova N. N. Sadykov V. A. Snegurenko O. I. Rogov V. A. Moroz E. M. Zolotarskii I. A. Simakov A. V. Parmon V. N. 《Kinetics and Catalysis》2004,45(4):589-597
The activity of Ni, Pt, and LaNiO3 supported on -Al2O3 is studied in the selective catalytic oxidation of methane to syngas at 900°C and a contact time of 0.002 s using dilute mixtures (1000 ppm CH4 + 500 ppm O2 in He). The grain size was 100 m. The method of X-ray phase analysis shows that supported LaNiO3, both pure and containing Pt, has a perovskite hexagonal structure with altered lattice parameters. Using temperature-programmed reduction by hydrogen, it was found that the reduction of supported LaNiO3 is simplified in the presence of Pt and/or Ce0.2Zr0.8O2. The activity and selectivity of the catalysts in the reaction of selective catalytic oxidation of methane depends on their composition and oxidative-reductive treatment. It was found that, in the presence of catalysts based on LaNiO3 and containing Pt and/or Ce0.2Zr0.8O2, the reaction occurs with an induction period. It was assumed that the value of the induction period depends both on the dynamics of phase LaNiO3 reduction to Ni, which is associated with the accumulation of carbonate complexes and surface hydroxylation, and on slow changes in the defect structure of Ce0.2Zr0.8O2, which are associated with oxidation-reduction. 相似文献
998.
Reaction of [Mn6(O)2Piv10(Thf)4].Thf with 2,4,4,5,5-pentamethyl-4,5-dihydro-1H-imidazolyl-3-oxide-1-oxyl (NIT-Me) produces different heterospin compounds depending of the solvent used in the synthesis. Among the latter a new molecular magnet [Mn6(O)2Piv10(Thf)2(NIT-Me)Mn6(O)2Piv10(Thf)(CH2Cl2)(NIT-Me)] with Tc = 3.5 K has been found. 相似文献
999.
1000.
Galina Perelman 《Communications in Mathematical Physics》2003,234(2):359-381
The stability of the absolutely continuous spectrum of the one-dimensional Stark operator
under perturbations of the potential is discussed. The focus is on proving this stability under minimal assumptions on smoothness
of the perturbation. A general criterion is presented together with some applications. These include the case of periodic
perturbations where we show that any perturbation vL
1
(𝕋)∩H
−1/2
(𝕋) preserves the a.c. spectrum.
Received: 26 June 2002 / Accepted: 30 September 2002 Published online: 20 January 2003
Communicated by B. Simon 相似文献