全文获取类型
收费全文 | 50829篇 |
免费 | 1678篇 |
国内免费 | 180篇 |
专业分类
化学 | 27721篇 |
晶体学 | 281篇 |
力学 | 1350篇 |
综合类 | 6篇 |
数学 | 8662篇 |
物理学 | 14667篇 |
出版年
2023年 | 304篇 |
2021年 | 452篇 |
2020年 | 628篇 |
2019年 | 514篇 |
2018年 | 708篇 |
2017年 | 675篇 |
2016年 | 1377篇 |
2015年 | 1090篇 |
2014年 | 1237篇 |
2013年 | 2587篇 |
2012年 | 2393篇 |
2011年 | 2592篇 |
2010年 | 1720篇 |
2009年 | 1480篇 |
2008年 | 2373篇 |
2007年 | 2255篇 |
2006年 | 2188篇 |
2005年 | 1971篇 |
2004年 | 1723篇 |
2003年 | 1350篇 |
2002年 | 1223篇 |
2001年 | 1051篇 |
2000年 | 889篇 |
1999年 | 644篇 |
1998年 | 569篇 |
1997年 | 542篇 |
1996年 | 674篇 |
1995年 | 564篇 |
1994年 | 597篇 |
1993年 | 606篇 |
1992年 | 658篇 |
1991年 | 484篇 |
1990年 | 483篇 |
1989年 | 460篇 |
1988年 | 420篇 |
1987年 | 421篇 |
1986年 | 401篇 |
1985年 | 606篇 |
1984年 | 592篇 |
1983年 | 482篇 |
1982年 | 518篇 |
1981年 | 519篇 |
1980年 | 508篇 |
1979年 | 493篇 |
1978年 | 479篇 |
1977年 | 462篇 |
1976年 | 450篇 |
1975年 | 428篇 |
1974年 | 411篇 |
1973年 | 360篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
941.
The spin dynamics of muons interacting with acceptor impurity nuclei in silicon is investigated. Using values of electric field gradients obtained from ab-initio calculations, the field dependence of the longitudinal muon polarization is calculated for SiB and SiAl and compared to the contributions from paramagnetic bond-center muonium. 相似文献
942.
M. Müther E. Bill A. X. Trautwein D. Mandon R. Weiss A. Gold K. Jayaraj R. N. Austin 《Hyperfine Interactions》1994,91(1):803-808
In order to study structural influences on the interaction of Fe(IV) (S=1) and porphyrin cation radical (S=1/2) in high-valent iron porphyrin complexes of the type ¦X-(TMP)Fe=O¦+(Cl–), X=I, Br2, Br4 were generated by mCPBA oxidation of corresponding Fe(III) porphyrins. The halogen substitution at the peripheral positions of the porphyrin leads to distortion of the planar porphyrin ring of ¦(TMP)Fe=O¦+. The new species have beeen investigated by temperature-dependent EPR and field-dependent Mössbauer spectroscopy; for the evaluation of spectra, we adopted the spin-Hamiltonian formalism including exchange interaction explicitly. As in ¦(TMP)Fe=O¦+, strong ferromagnetic spin coupling was observed with|J0|D=0.9–1 and a zero-field spltting ofD32 cm–1. For consistent parametrization of EPR and Mössbauer results, anisotropic coupling had to be introduced. Compared to ¦(TMP)Fe=O¦+ [1], analysis of the spectroscopic data shows that zero-field splitting and spin coupling is only slightly affected by the halogen distortion of the porphyrin structure. 相似文献
943.
944.
945.
946.
947.
948.
949.
The present paper studies the properties of Hubbard-like models in high spatial dimensionsD. In a first par the limit of infinite dimension and its main features-i.e.i) the mapping onto a generalized atomic model with an additional auxiliary field andii) the validity of the local approximation for the self-energy-are worked out in a systematic (1/D)-expansion. Since the hopping matrix elements have to be properly scaled with the dimensionD, the (1/D)-expansion is also an expansion in the hopping amplitude. Thus for small hopping theD-limit may serve as a proper approximation for finite-dimensional systems. The second part of the paper adopts the hybridisation-perturbation theory of the single impurity Anderson model in order to construct a perturbation theory for the auxiliary field of the generalized atom which can also be interpreted as an expansion in the hopping amplitude. The non-crossing approximation (NCA) is used to study the antiferromagnetic phase transtion of theD-Hubbard model in the case of half filling: the critical temperature, the antiferromagnetic order parameter and the free energy of the lattice system are calculated. The NCA-results are in quite good agreement with recent results from the imaginary-time discretisation method. 相似文献
950.
B. D. Valnion W. Oelmaier D. Hofer E. Zanotti-Müller G. Graw U. Atzrott F. Hoyler G. Staudt 《Zeitschrift für Physik A Hadrons and Nuclei》1994,350(1):11-12
A search for the recently proposed two-phonon octupole vibrational (2-POV) 4+ or 6+ state in208Pb at an excitation energy of 5683 keV has been performed using the207Pb(d,p),208Pb (p,p) and (,) reactions at high energy resolution. No evidence for a two-phonon excitation at this energy is found.This work was supported in part by the DFG under contract nr. II C4-Gr 894/2-1 and by the DFG-Graduiertenkolleg Struktur der Hadronen und Kerne under contract nr. Mu 705/3-1. 相似文献