全文获取类型
收费全文 | 49726篇 |
免费 | 2042篇 |
国内免费 | 19篇 |
专业分类
化学 | 32181篇 |
晶体学 | 244篇 |
力学 | 1588篇 |
数学 | 7709篇 |
物理学 | 10065篇 |
出版年
2023年 | 386篇 |
2022年 | 298篇 |
2021年 | 503篇 |
2020年 | 693篇 |
2019年 | 650篇 |
2018年 | 1019篇 |
2017年 | 825篇 |
2016年 | 1582篇 |
2015年 | 1454篇 |
2014年 | 1451篇 |
2013年 | 2984篇 |
2012年 | 3456篇 |
2011年 | 3511篇 |
2010年 | 2138篇 |
2009年 | 1733篇 |
2008年 | 3031篇 |
2007年 | 3042篇 |
2006年 | 2683篇 |
2005年 | 2593篇 |
2004年 | 2209篇 |
2003年 | 1794篇 |
2002年 | 1561篇 |
2001年 | 930篇 |
2000年 | 776篇 |
1999年 | 555篇 |
1998年 | 418篇 |
1997年 | 374篇 |
1996年 | 478篇 |
1995年 | 304篇 |
1994年 | 357篇 |
1993年 | 369篇 |
1992年 | 391篇 |
1991年 | 334篇 |
1990年 | 324篇 |
1989年 | 314篇 |
1988年 | 255篇 |
1987年 | 256篇 |
1986年 | 224篇 |
1985年 | 384篇 |
1984年 | 350篇 |
1983年 | 238篇 |
1982年 | 332篇 |
1981年 | 318篇 |
1980年 | 276篇 |
1979年 | 271篇 |
1978年 | 254篇 |
1976年 | 267篇 |
1975年 | 243篇 |
1974年 | 248篇 |
1973年 | 238篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
The computation of long wave propagation through the ocean obviously depends on the initial condition. When the waves are generated by a moving bottom, a traditional approach consists in translating the ‘frozen’ sea bed deformation to the free surface and propagating it. The present study shows the differences between the classical approach (passive generation) and the active generation where the bottom motion is included. The analytical solutions presented here exhibit some of the drawbacks of passive generation. The linearized solutions seem to be sufficient to consider the generation of water waves by a moving bottom. To cite this article: D. Dutykh et al., C. R. Acad. Sci. Paris, Ser. I 343 (2006). 相似文献
152.
Alexander Semenov Aurélia Charlot Rachel Auzély-Velty Marguerite Rinaudo 《Rheologica Acta》2007,46(5):541-568
Dynamics of associating polymer solutions above the reversible gelation point are studied. Each macromolecule consists of
a soluble backbone (B) and a small fraction of specific strongly interacting groups (A or C stickers) attached to B. A mixture
of B–A and B–C associating polymers with 1:1 stoichiometric ratio is considered. As a result of AC association, the polymers
reversibly gelate above the overlap concentration. It is shown that (1) the network strands are linear complexes (double chains)
of B–A and B–C; (2) “diffusion” of the network junction points is characterized by an apparent activation energy, which can
be significantly higher than the energy of one AC bond; (3) most importantly, the randomness of sticker distribution along
the chain can significantly slow down the network relaxation leading to a markedly non-Maxwellian viscoelastic behavior. The
theory elucidates the most essential features of rheological behavior of polysaccharide associating systems (with A = adamantyl
moiety, C = β-cyclodextrin, B = either chitosan or hyaluronan) including similar behavior of G
′ and G
″ in a wide frequency range, strong temperature dependence of the characteristic frequency ω
x
, and an extremely strong effect of added free stickers (fC) on the dynamics.
This paper was presented at Annual European Rheology Conference (AERC) held in Hersonisos, Crete, Greece, April 27–29, 2006. 相似文献
153.
154.
A. Veiga N. Martínez P. Mendoza Zélis G. A. Pasquevich F. H. Sánchez 《Hyperfine Interactions》2006,167(1-3):905-909
A prototype of a programmable constant-velocity scaler is presented. This instrument allows the acquisition of partial Mössbauer spectra in selected energy regions using standard drivers and transducers. It can be fully operated by a remote application, thus data acquisition can be automated. The instrument consists of a programmable counter and a constant-velocity reference. The reference waveform generator is amplitude modulated with 13-bit resolution, and is programmable in a wide range of frequencies and waveforms in order to optimize the performance of the transducer. The counter is compatible with most standard SCA, and is configured as a rate-meter that provides counts per selectable time slice at the programmed velocity. As a demonstration of the instrument applications, a partial Mössbauer spectrum of a natural iron foil was taken. Only positive energies were studied in 512 channels, accumulating 20 s per channel. A line width of 0.20 mm/s was achieved, performing with an efficiency of 80%. 相似文献
155.
The lanthanide sulfotellurides (LS)2Te1+x (0 ≤ x < 0.50) show order-disorder phenomena. Above 450°C, they crystallize in a partially disordered structure, orthorhombic with cell parameters a, b, and c close to 4.1, 5.2, and 13.6 Å, respectively. This structure is determined from diffractometer data on a (HoS)2Te1.34 crystal (R = 0.061). It is built up along the c axis from (L4S) tetrahedra layers, separated by Te planes. Disorder and nonstoichiometry are related to the two vacant Te sites. 相似文献
156.
Nikolaií N. Nekhoroshev Dmitrií A. Sadovskií Boris I. Zhilinskií 《Annales Henri Poincare》2006,7(6):1099-1211
We introduce fractional monodromy in order to characterize certain non-isolated critical values of the energy–momentum map
of integrable Hamiltonian dynamical systems represented by nonlinear resonant two-dimensional oscillators. We give the formal
mathematical definition of fractional monodromy, which is a generalization of the definition of monodromy used by other authors
before. We prove that the 1:( − 2) resonant oscillator system has monodromy matrix with half-integer coefficients and discuss
manifestations of this monodromy in quantum systems.
Communicated by Eduard Zehnder
Submitted: February 25, 2005; Accepted: November 17, 2005 相似文献
157.
The aim of this article is to give a new dynamical proof of the Ferrand–Obata theorem when the manifold is compact. This will give us a generalisation of this theorem to transversally conformal foliations ofcodimension greater than three and constant basic functions. 相似文献
158.
159.
Bruno Després 《Comptes Rendus Mathematique》2006,342(1):73-78
We describe a Weak Rankine Hugoniot relation for constrained discontinuous solutions of conservation laws. The constraint is convex in the primitive variable. Various examples show the potential interest of this approach. To cite this article: B. Després, C. R. Acad. Sci. Paris, Ser. I 342 (2006). 相似文献
160.