全文获取类型
收费全文 | 2913篇 |
免费 | 112篇 |
国内免费 | 10篇 |
专业分类
化学 | 1545篇 |
晶体学 | 9篇 |
力学 | 128篇 |
数学 | 681篇 |
物理学 | 672篇 |
出版年
2023年 | 34篇 |
2022年 | 43篇 |
2021年 | 39篇 |
2020年 | 58篇 |
2019年 | 51篇 |
2018年 | 40篇 |
2017年 | 41篇 |
2016年 | 114篇 |
2015年 | 105篇 |
2014年 | 101篇 |
2013年 | 151篇 |
2012年 | 171篇 |
2011年 | 236篇 |
2010年 | 130篇 |
2009年 | 84篇 |
2008年 | 162篇 |
2007年 | 145篇 |
2006年 | 147篇 |
2005年 | 129篇 |
2004年 | 102篇 |
2003年 | 92篇 |
2002年 | 65篇 |
2001年 | 50篇 |
2000年 | 42篇 |
1999年 | 18篇 |
1998年 | 29篇 |
1997年 | 21篇 |
1996年 | 31篇 |
1995年 | 40篇 |
1994年 | 27篇 |
1993年 | 20篇 |
1992年 | 35篇 |
1991年 | 16篇 |
1990年 | 25篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 19篇 |
1985年 | 26篇 |
1984年 | 17篇 |
1983年 | 20篇 |
1982年 | 25篇 |
1981年 | 19篇 |
1980年 | 16篇 |
1979年 | 16篇 |
1978年 | 15篇 |
1977年 | 20篇 |
1976年 | 17篇 |
1975年 | 13篇 |
1974年 | 14篇 |
1973年 | 16篇 |
排序方式: 共有3035条查询结果,搜索用时 31 毫秒
2.
Lagrangian and Eulerian modelling approaches are compared for simulating turbulent dispersion and coalescence of droplets within a spray. Both models predict similar droplet dispersion rates and shifts in droplet size distribution due to coalescence within the spray, over a wide range of droplet and gas flows, and for sprays with different droplet-size distributions at the nozzle exit. The computer time required for simulating coalescence within a steady axisymmetric spray is of a similar order of magnitude regardless of which formulation, Eulerian or Lagrangian, is adopted. However, the Lagrangian formulation is more practical in terms of the range of applicability and ease of implementation. 相似文献
3.
4.
5.
Laura Bader Nicola Durante Maska Law Guglielmo Lunardon Tim Penttila 《Designs, Codes and Cryptography》2003,29(1-3):41-50
We do the tentative beginnings of a study of BLT-sets of generalised quadrangles via their symmetries. In particular, the study of whorls about a line leads us to hyperbolic reflections preserving a BLT-set of Q(4, q). 相似文献
6.
7.
R. Klein R. Grieser L. Hoog G. Huber I. Klaft P. Merz T. Kühl S. Schröder M. Grieser D. Habs W. Petrich D. Schwalm 《Zeitschrift für Physik A Hadrons and Nuclei》1992,342(4):455-461
We have performed for the first time precision spectroscopy on a coasting fast7Li+ ion beam in a storage ring. The ion beam moving with 6.4% speed of light was first electron cooled and then merged with two counterpropagating laser beams acting on two different hyperfine transitions sharing a common upper level (λ-system). One laser was frequency locked to thea 3 127J2 hfs frequency component established as a secondary frequency standard at 514 nm. The second laser was tuned over theλ-resonance, which was recorded relative to127J2 hfs components. This experiment is sensitive to the time dilation in fast moving frames and will lead to new limits for the verification of special relatively. The present status of the experiment and perspectives in accuracy are discussed. 相似文献
8.
9.
Tim R. Dargaville Julie M. Elliott Mathew Celina 《Journal of Polymer Science.Polymer Physics》2006,44(22):3253-3264
Films of piezoelectric PVDF and P(VDF‐TrFE) were exposed to vacuum UV (115–300 nm VUV) and γ‐radiation to investigate how these two forms of radiation affect the chemical, morphological, and piezoelectric properties of the polymers. The extent of crosslinking was almost identical in both polymers after γ‐irradiation, but surprisingly, was significantly higher for the TrFE copolymer after VUV‐irradiation. Changes in the melting behavior were also more significant in the TrFE copolymer after VUV‐irradiation due to both surface and bulk crosslinking, compared with only surface crosslinking for the PVDF films. The piezoelectric properties (measured using d33 piezoelectric coefficients and D‐E hysteresis loops) were unchanged in the PVDF homopolymer, while the TrFE copolymer exhibited more narrow D‐E loops after exposure to either γ‐ or VUV‐radiation. The more severe damage to the TrFE copolymer in comparison with the PVDF homopolymer after VUV‐irradiation is explained by different energy deposition characteristics. The short wavelength, highly energetic photons are undoubtedly absorbed in the surface layers of both polymers, and we propose that while the longer wavelength components of the VUV‐radiation are absorbed by the bulk of the TrFE copolymer causing crosslinking, they are transmitted harmlessly in the PVDF homopolymer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3253–3264, 2006 相似文献
10.
R. Lacaze A. Morel B. Petersson J. Schröper 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,2(4):509-523
We present an investigation of the 2D attractive Hubbard model, considered as an effective model relevant to superconductivity
in strongly interacting electron systems. We use both hybrid Monte-Carlo simulations and existing hopping parameter expansions
to explore the low temperature domain. The increase of the static S-wave pair correlation with decreasing temperature, which depends weakly on the band filling in the explored temperature range,
is analyzed in terms of an expected Kosterlitz-Thouless superconducting transition. Using both our data and previously published
results, we show that the evidence for this transition is weak: If it exists, its temperature is very low. The number of unpaired
electrons remains nearly constant with temperature at fixed attractive potential strength. In contrast, the static magnetic
susceptibility decreases fast with temperature, and cannot be related only to pair formation. We introduce a method by which
the Padé approximants of the existing series for the susceptibility give sensible results down to rather low temperature region,
as shown by comparison with our numerical data.
Received: 30 October 1996 / Revised: 23 October 1997 / Accepted: 29 January 1998 相似文献