全文获取类型
收费全文 | 459篇 |
免费 | 22篇 |
国内免费 | 1篇 |
专业分类
化学 | 338篇 |
晶体学 | 1篇 |
力学 | 6篇 |
数学 | 26篇 |
物理学 | 111篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 5篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 7篇 |
2017年 | 9篇 |
2016年 | 13篇 |
2015年 | 10篇 |
2014年 | 12篇 |
2013年 | 33篇 |
2012年 | 23篇 |
2011年 | 38篇 |
2010年 | 22篇 |
2009年 | 19篇 |
2008年 | 29篇 |
2007年 | 32篇 |
2006年 | 24篇 |
2005年 | 32篇 |
2004年 | 18篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 2篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1971年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有482条查询结果,搜索用时 31 毫秒
71.
Michael F. Barnsley Jacques G. Aguilar 《International journal of quantum chemistry》1978,13(5):641-677
Let E(R) be a potential-energy function for a neutral or ionic diatom in the Born-Oppenheimer approximation. Then the approximation of E(R) for 0 < R < ∞ starting from finite and typically small sets of given information is considered. The approach is based on the fact that the scaled potential curves F(R) = R2E(R) derive from an eigenvalue problem which depends linearly on R. The nature of the curves F(R) is examined in detail. The results include the discovery of various approximants, some of which display rigorous bounding properties and others, closely related, whose behavior with respect to the approximated function appears to be predictable. 相似文献
72.
Hodacová J Chadim M Závada J Aguilar J García-España E Luis SV Miravet JF 《The Journal of organic chemistry》2005,70(6):2042-2047
[structure: see text] The interaction of a macrocycle containing three trans-(1R,2R)-diaminocyclohexane units connected by p-xylene spacers with the isomers 1,3,5-benzenetricarboxylic (1,3,5-BTC), 1,2,4-benzenetricarboxylic (1,2,4-BTC), and 1,2,3-benzenetricarboxylic (1,2,3-BTC) acids and their relevant anions is studied by means of potentiometric and NMR analysis. The interaction is highest for the isomer 1,3,5-BTC, which perfectly fits within the macrocyclic cavity of the host species. The studies have been extended to the triacid 1,3,5-benzenetriacetic observing in this case the effect of a size mismatch between host and guest species. 相似文献
73.
Classic simulations are used to study interlayer structure, swelling curves, and stability of Ca-montmorillonite hydrates. For this purpose, NP(zz)T and muP(zz)T ensembles are sampled for ground level and given burial conditions. For ground level conditions, a double layer hydrate having 15.0 A of basal spacing is the predominant state for relative vapor pressures (p/p0) ranging 0.6-1.0. A triple hydrate counting on 17.9 A of interlaminar distance was also found stable for p/p0 = 1.0. For low vapor pressures, the system may produce a less hydrated but still double layer state with 13.5 A or even a single layer hydrate with 12.2 A of interlaminar distance. This depends on the established initial conditions. On the other hand, the effect of burial conditions is two sided. It was found that it enhances dehydration for all vapor pressures except for saturation, where swelling is promoted. 相似文献
74.
An effective hamiltonian method based on a one-electron potential is proposed. The potential is represented by a sum of two coulombic interactions with effective nuclear charges depending upon the internuclear distance. This potential preserves the separability of Schrödinger equation. The method can be usefully applied to various atom (ion)-atom collision problems. Calculations are carried out for some states of HeH+ and HeH using one configuration built up from a minimal basis set chosen to ensure correct dissociation. 相似文献
75.
M. Aguilar G. J. Rubio O. F.J. López J. Garciá-Solé H.S. Murrieta 《Solid State Communications》1982,44(2):141-144
Europium precipitation in monocrystalline KBR has been studied using optical absorption and photoluminescence techniques. The annealing of quenched samples at temperatures below 100°C produces the growth of an emission band peaking at 433 nm which appears to be related with the presence of Suzuki-type precipitates in the crystals. The aging at higher temperatures, however, produces the appearence in the emission spectrum of two other bands peaking at 427 and 459 nm. The data presented in this paper strongly suggest that the former band is associated with the stable dihalide phase EuBr2 in the host KBr, while the latter is due to a metastable precipitate whose structure appears to be quite similar to that of europium bromide. Some of the characteristics of the second phase precipitates were obtained by measuring the crystal field splitting (10 Dq) of the 4f65d configuration of the Eu2+ ions in each one of them. 相似文献
76.
M. Vlasova P.A. Márquez Aguilar M. Kakazey V. Stetsenko A. Ragulya 《Optics & Laser Technology》2010,42(1):8-17
The laser treatment of two-layer Si-Al2O3 target at λ=1064 nm and P=170 W in a N2+O2 atmosphere by electron microscopy, atomic force microscopy, X-ray microanalysis, and IR-spectroscopy was investigated. It is established that in the stage of fracture of a silicon plate, the ablation products were silicon clusters into which, when passing over, oxygen and nitrogen diffused. On collective plate, a SiOxN composite film formed. In the stage of fracture of an alumina plate, the oxidation of silicon in the channel zone and the interaction of Al and Si oxides, accompanied by their nitration, occurred. In this stage, evolved oxide vapors and ejected mullite drops deposit on the SiOxN film. On collective plate, mullite nanowhiskers grew from mullite drops by the vapor-liquid-solid body mechanism. 相似文献
77.
P.A. Márquez Aguilar M. Vlasova D. Mayorga Cruz V. Stetsenko A. Ragulya 《Optics & Laser Technology》2010,42(1):172-179
Using electron microscopy and X-ray microanalysis, the formation of tracks by laser processing of AlN:Y2O3 ceramic surfaces was investigated. The main process of channel formation is the decomposition of aluminum nitride (AlN). Due to aluminothermic reduction of Y2O3, the metallization of channel surfaces occurs. The main products of ablation are Al2O3, AlN, and AlON. 相似文献
78.
Kilcoyne AL Aguilar A Müller A Schippers S Cisneros C Alna'washi G Aryal NB Baral KK Esteves DA Thomas CM Phaneuf RA 《Physical review letters》2010,105(21):213001
Experimental evidence is presented for confinement resonances associated with photoabsorption by a Xe atom in a C60 cage. The giant 4d resonance in photoionization of Xe is predicted to be redistributed into four components due to multipath interference of photoelectron waves reflected by the cage. The measurements were made in the photon energy range 60-150 eV by merging a beam of synchrotron radiation with a mass/charge selected Xe@C??+ ion beam. The phenomenon was observed in the Xe@C(58)(3+) product ion channel. [corrected] 相似文献
79.
Aamodt K Abelev B Quintana AA Adamová D Adare AM Aggarwal MM Rinella GA Agocs AG Salazar SA Ahammed Z Masoodi AA Ahmad N Ahn SU Akindinov A Aleksandrov D Alessandro B Molina RA Alici A Alkin A Aviña EA Alt T Altini V Altinpinar S Altsybeev I Andrei C Andronic A Anguelov V Anson C Antičić T Antinori F Antonioli P Aphecetche L Appelshäuser H Arbor N Arcelli S Arend A Armesto N Arnaldi R Aronsson T Arsene IC Asryan A Augustinus A Averbeck R Awes TC Aystö J Azmi MD Bach M Badalà A Baek YW 《Physical review letters》2010,105(25):252301
The first measurement of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair √ S NN = 2.76 TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section, the pseudorapidity density of primary charged particles at midrapidity is 1584 ± 4(stat) ± 76(syst), which corresponds to 8.3 ± 0.4(syst) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at √ S NN = 2.76 TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies. 相似文献
80.
Aamodt K Abelev B Quintana AA Adamová D Adare AM Aggarwal MM Rinella GA Agocs AG Salazar SA Ahammed Z Masoodi AA Ahmad N Ahn SU Akindinov A Aleksandrov D Alessandro B Molina RA Alici A Alkin A Aviña EA Alt T Altini V Altinpinar S Altsybeev I Andrei C Andronic A Anguelov V Anson C Antičić T Antinori F Antonioli P Aphecetche L Appelshäuser H Arbor N Arcelli S Arend A Armesto N Arnaldi R Aronsson T Arsene IC Asryan A Augustinus A Averbeck R Awes TC Aystö J Azmi MD Bach M Badalà A Baek YW 《Physical review letters》2010,105(25):252302
We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at sqrt[S(NN)] =2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η|<0.8) and transverse momentum range 0.2
相似文献