全文获取类型
收费全文 | 2474篇 |
免费 | 80篇 |
国内免费 | 9篇 |
专业分类
化学 | 1538篇 |
晶体学 | 13篇 |
力学 | 120篇 |
数学 | 363篇 |
物理学 | 529篇 |
出版年
2024年 | 3篇 |
2023年 | 19篇 |
2022年 | 57篇 |
2021年 | 67篇 |
2020年 | 70篇 |
2019年 | 57篇 |
2018年 | 58篇 |
2017年 | 52篇 |
2016年 | 103篇 |
2015年 | 91篇 |
2014年 | 90篇 |
2013年 | 175篇 |
2012年 | 179篇 |
2011年 | 208篇 |
2010年 | 140篇 |
2009年 | 134篇 |
2008年 | 182篇 |
2007年 | 140篇 |
2006年 | 121篇 |
2005年 | 109篇 |
2004年 | 81篇 |
2003年 | 91篇 |
2002年 | 76篇 |
2001年 | 30篇 |
2000年 | 27篇 |
1999年 | 23篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 22篇 |
1995年 | 8篇 |
1994年 | 11篇 |
1993年 | 13篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 6篇 |
排序方式: 共有2563条查询结果,搜索用时 9 毫秒
11.
J. C. Fabris S. V. B. Gonçalves P. E. de Souza 《General Relativity and Gravitation》2002,34(12):2111-2126
The mass power spectrum for a Universe dominated by the Chaplygin gas is evaluated numerically from scales of the order of the Hubble horizon to 100 Mpc. The results are compared with a pure baryonic Universe and a cosmological constant model. In all three cases, the spectrum increases with k, the wavenumber of the perturbations. The slope of the spectrum is higher for the baryonic model and smaller for the cosmological constant model, the Chaplygin gas interpolating these two models. The results are analyzed in terms of the sound velocity of the Chaplygin gas and the moment the Universe begins to accelerate. 相似文献
12.
Steatite mineral rocks, soapstone, have been studied by X-ray diffraction, optical microscopic analysis (modal analysis), electron probe micro analysis and Mössbauer spectroscopy for characterization, mineral percentages and chemical composition. Mössbauer spectra show both, magnetic interactions corresponding to magnetite and doublets corresponding to talc. chlorite, dolomite and tremolite. The temperature dependence of the quadrupole splitting in dolomite has been explained in terms of crystal field interaction. 相似文献
13.
Rafael Dias do Espírito Santo Rosineide Costa Simas Alviclér Magalhães Vanessa Gonçalves dos Santos Thais Regiani Ana Cristina Isler Natiza Graziele Martins Marcos Nogueira Eberlin Eduardo René Pérez González 《Journal of Physical Organic Chemistry》2013,26(4):315-321
Molecules containing the guanidinic nuclei possess several pharmacological applications, and knowing the preferred isomers of a potential drug is important to understand the way it operates pharmacologically. Benzoylguanidines were synthesized in satisfactory to good yields and characterized by NMR, Electrospray Ionization Mass Spectrometry (ESI‐MS) and Fourrier Transform InfraRed Spectroscopy techniques (FTIR). E/Z isomerism of the guanidines was studied and confirmed by NMR analysis in solution (1H‐13C Heteronuclear Single Quantum Coherence (HSQC) and Heteronuclear Multiple‐Bond Correlation (HMBC), 1H‐15N HMBC, 1H‐1H Correlation Spectroscopy (COSY) and Nuclear Overhauser Effect Spectroscopy (NOESY) experiments) at low temperatures. Compounds with p‐Cl and p‐Br aniline moiety exist mainly as Z isomer with a small proportion of E isomer, whereas compounds with p‐NO2 moiety showed a decrease in proportion of isomer Z. The results are important for the application of these molecules as enzymatic inhibitors. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
14.
M.H.P. Corrêa A. Vasquez M.I. da Costa P.J. Viccaro C.E.T. Gonçalves da Silva 《Solid State Communications》1981,40(3):211-213
Ordered alloys of Pd3Fe are shown to readily absorbe hydrogen through electrolytic loading. The resultant ternary hydride phase is observed to retain the fcc structure of Pd3Fe with approximately the same lattice constant. The 57Fe hyperfine field determined by Mössbauer spectroscopy is found to be 30% smaller in the hydride compared to Pd3Fe. The reduction appears to be associated with a perturbation of the Pd moment by hydrogen. The results suggest the occupation of one type of interstitial site in the structure. The absence of the site in disordered Pd3Fe would explain the much smaller hydrogen capacity observed for this alloy. 相似文献
15.
16.
17.
The global formulation of the higher-order Poincaré-Cartan form for Lagrangian field theories in the calculus of variations is re-examined in terms of the theory of lifts of tensor fields on a manifold to its higher-order prolongated jet bundles.Partially supported by CNPq, Brazil, Proc. MA 30.1115/79. 相似文献
18.
C.E.T. Gonçalves da Silva 《Solid State Communications》1979,30(5):283-287
The magnetic properties of an intermediate valence compound are discussed within a single-ion framework. The effects of configuration mixing, crystalline electric fields, and external magnetic fields are included in the hamiltonian. The method incorporates in one single consistent approach both coherent (quantum) and incoherent (thermal) fluctuations. Numerical evaluation of the susceptibility and field dependent magnetization with parameters appropriate for TmSe yields results in good agreement with experiment. 相似文献
19.
Anisha Gokarna Yong Hwan Kim Yong-Hoon Cho Min Su Lee In Cheol Kang Hyun Kyu Park Min Gon Kim Bong Hyun Chung 《Optical Review》2006,13(4):288-291
We demonstrate the fluorescence mapping of protein microarrays by the technique of scanning near-field optical microscopy
(SNOM) and confocal microscopy. Micron sized spots (300 μm) of human Immunoglobulin G (hIgG) protein with and without a Cy3
dye labeling have been fabricated on glass substrates by an immobilization method which makes use of calixcrown derivatives
termed Prolinker. We have also tried to probe into the well-known “doughnut effect” observed in fluorescence images of proteins
using the SNOM technique. The topographic and fluorescence SNOM images revealed that the number of proteins at the boundary
of the spot were more than at the center in the case of the microarray spot which showed brighter luminescence at the edge
than at the center in the confocal image. 相似文献