全文获取类型
收费全文 | 292篇 |
免费 | 7篇 |
专业分类
化学 | 123篇 |
晶体学 | 9篇 |
力学 | 8篇 |
数学 | 8篇 |
物理学 | 151篇 |
出版年
2024年 | 1篇 |
2022年 | 10篇 |
2021年 | 17篇 |
2020年 | 12篇 |
2019年 | 9篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 17篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 14篇 |
2012年 | 18篇 |
2011年 | 24篇 |
2010年 | 12篇 |
2009年 | 10篇 |
2008年 | 18篇 |
2007年 | 10篇 |
2006年 | 9篇 |
2005年 | 8篇 |
2004年 | 12篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有299条查询结果,搜索用时 15 毫秒
1.
S. F. Dubinin V. E. Arkhipov S. G. Teploukhov V. D. Parkhomenko 《Physics of the Solid State》2003,45(11):2147-2151
The {1/2, 0, 1/2} nuclear superstructure in an La0.93Sr0.07MnO3 manganite orthorhombic crystal is revealed using thermal-neutron diffraction. It is demonstrated that this superlattice belongs to the class of distortion-type structures and is directly associated with a 1/16-type ordering of Mn4+ and Mn3+ ions in a collinear ferromagnetic phase of the La0.93Sr0.07MnO3 manganite. 相似文献
2.
3.
S. F. Dubinin V. E. Arkhipov Yu. G. Chukalkin S. G. Teploukhov V. D. Parkhomenko Ya. M. Mukovskiĭ 《Physics of the Solid State》2007,49(2):308-314
The magnetic structure and transport properties of partially disordered crystals of two-dimensional manganites La2?2x Sr1+2x Mn2O7 (x = 0.3, 0.4) are studied over a wide range of temperatures. The crystals are transformed into an atomically disordered state under irradiation with fast neutrons at a dose of 2 × 1019 cm?2. The average concentration of substitutional defects in the crystal is ≈4%. It is found that substitutional defects are responsible for the transition of these manganites from the ferromagnetic metal state to the insulator state with a spin glass structure. The results obtained are discussed in terms of the ratio between the kinetic energy of charge carriers and the exchange energy of localized spins. 相似文献
4.
Ksenia Pumpor Elisabeth Windeisen Klaus Burger 《Journal of heterocyclic chemistry》2003,40(3):435-442
The synthesis of heterocyclic α‐mercapto acids starting from (RS)‐thiomalic acid using hexafluoroacetone as protecting and activating agent is described. The new compounds are useful building blocks for peptide and depsipeptide modification as well as for drug design. 相似文献
5.
S.E. Parkhomenko 《Nuclear Physics B》1998,510(3):1116-639
Poisson-Lie T-duality in N = 2 superconformal WZNW models on the real Lie groups is considered. It is shown that Poisson-Lie T-duality is governed by the complexifications of the corresponding real groups endowed with Semenov-Tian-Shansky symplectic forms, i.e. Heisenberg doubles. Complex Heisenberg doubles are used to define on the group manifolds of the N = 2 superconformal WZNW models the natural actions of the isotropic complex subgroups forming the doubles. It is proved that with respect to these actions N = 2 superconformal WZNW models admit Poisson-Lie symmetries. The Poisson-Lie T-duality transformation maps each model onto itself but acts non-trivially on the space of classical solutions. 相似文献
6.
V. M. Pinchuk E. S. Kotlyarova N. V. Parkhomenko P. N. Tsybulev 《Journal of Structural Chemistry》1996,37(4):544-556
The studies concerned with the oxidation of carbon monoxide on the nickel surface are reviewed. The Eley-Rideal (ER) collision
and Langmuir-Hinshelwood (LH) adsorption mechanisms of the oxidation are analyzed. Calculations of the activation barriers
of the oxidation of carbon monoxide on the Ni (111), (100), and (110) faces were performed for the first time and involved
optimization of the reaction paths by the collision and adsorption mechanisms. It is shown that on the Ni (111) and (110)
faces the ER collision mechanism of the reaction is preferable with the activation barriers ΔE
dis
O
2=62 kJ/mole and ΔE
trans
O
A21F50012x=25 kJ/mole for Ni (111) and ΔE
dis
O
2=72 kJ/mole and ΔE
trans
O
2=20 kJ/mole for Ni (110); on the Ni (100) face, the LH adsorption mechanism with the activation barriers ΔE
dis
O
2=75 kJ/mole and ΔE
trans
O
2=42 kJ/mole is favored. Analysis of the potential barriers for the catalytic oxidation of carbon monoxide on the Ni surfaces
suggests the LH mechanism to be preferential, although insignificant differences in the activation barries can lead to the
oscillatory reaction mechanism, which is confirmed experimentally. The calculations were performed by the LCAO MO SCF method
in the MINDO/3 approximation.
Kiev Polytechnical Institute. Translated fromZhurnal Struktumoi Khimii, Vol. 37, No. 4, pp. 628–645, July–August, 1996.
Translated by I. Izvekova 相似文献
7.
Ksenia Shilyaeva Nils Elander Evgeny Yarevsky 《International journal of quantum chemistry》2007,107(6):1301-1315
Peaks in collision cross sections are often interpreted as resonances. The complex dilation method, as well as other methods relying on analytic continuation of the scattering formalism, can be used to clarify whether these structures are true resonances in the sense that they are poles of the S‐matrix and the associated Green function. The performance of the Mittag–Leffler expansion and T‐matrix Green function expansion methods are formally and computationally compared. The two methods are applied to two model potentials. Eigenenergies, s‐wave residues, and cross sections are computed with both methods. The resonance contributions to the cross sections are further analyzed by removing the residue contributions from the Mittag–Leffler and Green function expansion sums, respectively. It is suggested that the contribution of a resonance to a cross section should be defined through its S‐matrix residue. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 相似文献
8.
Electron ionization (EI) mass spectra of 46 compounds from several different compound classes were measured. Their molecular ion abundances were compared as obtained with 70‐eV EI, with low eV EI (such as 14 eV), and with EI mass spectra of vibrationally cold molecules in supersonic molecular beams (Cold EI). We further compared these mass spectra in their National Institute of Standards and Technology (NIST) library identification probabilities. We found that
- Low eV EI is not a soft ionization method, and it has little or no influence on the molecular ion relative abundances for large molecules and those with weak or no molecular ions.
- Low eV EI for compounds with abundant or dominant molecular ions in their 70 eV mass spectra results in the reduction of low mass fragment ions abundances thereby reducing their NIST library identification probabilities thus rarely justifies its use in real‐world applications.
- Cold EI significantly enhances the relative abundance of the molecular ions particularly for large compounds; yet, it retains the low mass fragment ions; hence, Cold EI mass spectra can be effectively identified by the NIST library.
- Different standard EI ion sources provide different 70 eV EI mass spectra. Among the Agilent technologies ion sources, the “Extractor” exhibits relatively abundant molecular ions compared with the “Inert” ion source, while the “High efficiency source” (HES) provides mass spectra with depleted molecular ions compared with the “Inert” ion source or NIST library mass spectra.
9.
10.