全文获取类型
收费全文 | 796篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
化学 | 544篇 |
晶体学 | 7篇 |
力学 | 14篇 |
数学 | 143篇 |
物理学 | 105篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 12篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 16篇 |
2015年 | 21篇 |
2014年 | 17篇 |
2013年 | 44篇 |
2012年 | 52篇 |
2011年 | 36篇 |
2010年 | 24篇 |
2009年 | 30篇 |
2008年 | 32篇 |
2007年 | 47篇 |
2006年 | 45篇 |
2005年 | 31篇 |
2004年 | 29篇 |
2003年 | 35篇 |
2002年 | 30篇 |
2001年 | 12篇 |
2000年 | 21篇 |
1999年 | 14篇 |
1998年 | 13篇 |
1997年 | 14篇 |
1996年 | 11篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 13篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 9篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 11篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1973年 | 5篇 |
1966年 | 3篇 |
1947年 | 5篇 |
排序方式: 共有813条查询结果,搜索用时 15 毫秒
51.
52.
53.
E.?Tomasi-GustafssonEmail author F.?Lacroix C.?Duterte G.?I.?Gakh 《The European Physical Journal A - Hadrons and Nuclei》2005,24(3):419-430
We perform a global analysis of the experimental data of the electromagnetic nucleon form factors, in space-like and time-like regions. We give the expressions of the observables in annihilation processes, such as p + ¯↦ℓ+ + ℓ-, ℓ = e or μ, in terms of form factors. We discuss some of the phenomenological models proposed in the literature for the space-like region, and consider their analytical continuation to the time-like region. After determining the parameters through a fit on the available data, we give predictions for the observables which will be experimentally accessible with large statistics, polarized annihilation reactions 相似文献
54.
Shevchenko A Carter J Fearick RW Förtsch SV Fujita H Fujita Y Kalmykov Y Lacroix D Lawrie JJ von Neumann-Cosel P Neveling R Ponomarev VY Richter A Sideras-Haddad E Smit FD Wambach J 《Physical review letters》2004,93(12):122501
Fine structure in the energy region of the isoscalar giant quadrupole resonance in nuclei is observed in high-resolution proton scattering experiments at iThemba LABS over a wide mass range. A novel method based on wavelet transforms is introduced for the extraction of scales characterizing the fine structure. A comparison with microscopic model calculations including two-particle two-hole (2p2h) degrees of freedom identifies the coupling to surface vibrations as the main source of the observed scales. A generic pattern is also found for the stochastic coupling to the background of the more complex states. 相似文献
55.
We discuss the ground state of a pyrochlore lattice of threefold orbitally degenerate S=1/2 magnetic ions. We derive an effective spin-orbital Hamiltonian and show that the orbital degrees of freedom can modulate the spin exchange, removing the infinite spin-degeneracy characteristic of pyrochlore structures. The resulting state is a collection of spin-singlet dimers, with a residual degeneracy due to their relative orientation. This latter is lifted by a magnetoelastic interaction, induced in the spin-singlet phase space, that forces a tetragonal distortion. Such a theory provides an explanation for the helical spin-singlet pattern observed in the B spinel MgTi2O4. 相似文献
56.
Kastelein RA Hagedoorn M Au WW de Haan D 《The Journal of the Acoustical Society of America》2003,113(2):1130-1137
The underwater hearing sensitivity of a striped dolphin was measured in a pool using standard psycho-acoustic techniques. The go/no-go response paradigm and up-down staircase psychometric method were used. Auditory sensitivity was measured by using 12 narrow-band frequency-modulated signals having center frequencies between 0.5 and 160 kHz. The 50% detection threshold was determined for each frequency. The resulting audiogram for this animal was U-shaped, with hearing capabilities from 0.5 to 160 kHz (8 1/3 oct). Maximum sensitivity (42 dB re 1 microPa) occurred at 64 kHz. The range of most sensitive hearing (defined as the frequency range with sensitivities within 10 dB of maximum sensitivity) was from 29 to 123 kHz (approximately 2 oct). The animal's hearing became less sensitive below 32 kHz and above 120 kHz. Sensitivity decreased by about 8 dB per octave below 1 kHz and fell sharply at a rate of about 390 dB per octave above 140 kHz. 相似文献
57.
Thanh Nam Nguyen Monique Thual Laurent Provino Nick Traynor 《Optics Communications》2007,278(1):60-65
We present a novel and simple method to measure both the value of the second-order dispersion coefficient and the nonlinear coefficient in optical fibers. This method is based on the higher-order soliton-effect pulse compression phenomenon and is valid for dispersion values greater than 0.5 ps/km/nm. A non-zero dispersion-shifted fiber, a standard single-mode fiber and a highly-dispersive highly-nonlinear fiber have been measured using this method. 相似文献
58.
1. INTRODUCTION Streptococcus pneumoniae remains an important cause of infections in this end of the 20th century and is responsible for invasive diseases - pneumonia, meningitis, bacteremia, septicemia - as well as for noninvasive diseases such as pharyngitis, conjunctivitis, otitis media.1,2 相似文献
59.
60.
C. Lacroix 《Journal of magnetism and magnetic materials》1986,60(2-3):145-152
A simple approach to the coherence effects in the Kondo lattice is presented, using the functional integral method. We show the existence of a coherence temperature Tc smaller than TK, below which coherence between impurities appears. The density of states is calculated in an approximation which takes into account coherent and incoherent scattering. We also show how the thermodynamic properties reflect the coherence effects. 相似文献