全文获取类型
收费全文 | 745篇 |
免费 | 0篇 |
专业分类
化学 | 442篇 |
晶体学 | 64篇 |
力学 | 19篇 |
数学 | 48篇 |
物理学 | 172篇 |
出版年
2021年 | 12篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2014年 | 5篇 |
2013年 | 20篇 |
2012年 | 10篇 |
2011年 | 25篇 |
2010年 | 23篇 |
2009年 | 44篇 |
2008年 | 22篇 |
2007年 | 23篇 |
2006年 | 29篇 |
2005年 | 32篇 |
2004年 | 21篇 |
2003年 | 24篇 |
2002年 | 14篇 |
2001年 | 28篇 |
2000年 | 20篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1996年 | 5篇 |
1994年 | 5篇 |
1993年 | 13篇 |
1992年 | 11篇 |
1991年 | 14篇 |
1990年 | 13篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 7篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1976年 | 16篇 |
1975年 | 15篇 |
1974年 | 12篇 |
1973年 | 13篇 |
1972年 | 10篇 |
1971年 | 16篇 |
1970年 | 26篇 |
1969年 | 12篇 |
1967年 | 9篇 |
1966年 | 5篇 |
排序方式: 共有745条查询结果,搜索用时 15 毫秒
741.
T. Volk B. Maximov T. Chernaya N. Rubinina M. Wöhlecke V. Simonov 《Applied physics. B, Lasers and optics》2001,72(6):647-652
LiNbO3:Zn single crystals and powders were studied by precise X-ray diffraction methods. Structural refinement yielded new models
of the intrinsic defect structure valid for different Zn concentration ranges. For concentrations up to 7 at. % in the crystal,
Zn ions incorporate onto Li sites; at higher concentrations Zn ions are found on both Li and Nb sites. Photorefractive properties
of LiNbO3:Zn are discussed in the context of the deduced defect models. A smooth increase in the photoconductivity up to 7 at. % Zn
is accounted for by a decrease of Nb antisites. Steeper growth of the photoconductivity at higher Zn concentrations is related
to vanishing Li vacancies.
Received: 17 November 2000 / Revised version: 23 January 2001 / Published online: 20 April 2001 相似文献
742.
743.
Liu Wen V. I. Voronkova V. K. Yanovskii N. I. Sorokina I. A. Verin V. I. Simonov 《Crystallography Reports》2000,45(3):380-385
The subsolidus region of the phase diagram of the RbTiOPO4-CsTiPO5 system has been studied in the temperature range 700–1000°C, and the boundaries between the stability fields of the orthorhombic phase with the KTiOPO4-type structure and the cubic phase with the pyrochlore-type structure have been determined. Single crystals of the RbTiOPO4 and CsTiPO5 based solid solutions were synthesized by crystallization from flux. The crystal structure and the physical properties of the first members of the series were studied. 相似文献
744.
T. Yu. Losevskaya O. A. Alekseeva V. K. Yanovskii V. I. Voronkova N. I. Sorokina V. I. Simonov S. Yu. Stefanovich S. A. Ivanov S. Eriksson S. A. Zverkov 《Crystallography Reports》2000,45(5):739-743
A series of potassium titanyl phosphate crystals, KTiOPO4, with various concentrations of niobium dopant has been grown, and some of their physical properties and structural characteristics have been studied. The incorporation of a small amount of niobium results in considerable changes in the electrical conductivity of KTP: Nb crystals and the temperature of the ferroelectric phase transition. Thus, the presence of 3–4 at. % of niobium results in an increase of conductivity by more than an order of magnitude, whereas T C decreases from 930 to 620°C. The X-ray diffraction study of the crystals has been performed at room temperature; the neutron diffraction analysis was made at temperatures of 20, 330, and 730°C. It was revealed that two crystallographically independent positions are statistically (by 90%) occupied by potassium cations, which results in the concentration of potassium atoms in the structure higher than it was expected from the condition of preservation of crystal electroneutrality. At high niobium concentrations, the monoclinic compound of the composition K2TiNb2P2O3 is formed. 相似文献
745.
Tamara A. Bazhenova Vyacheslav A. Kopotkov Denis V. Korchagin Yuriy V. Manakin Leokadiya V. Zorina Sergey V. Simonov Ilya A. Yakushev Vladimir S. Mironov Alexander N. Vasiliev Olga V. Maximova Eduard B. Yagubskii 《Molecules (Basel, Switzerland)》2021,26(22)
A series of six seven-coordinate pentagonal-bipyramidal (PBP) erbium complexes, with acyclic pentadentate [N3O2] Schiff-base ligands, 2,6-diacetylpyridine bis-(4-methoxybenzoylhydrazone) [H2DAPMBH], or 2,6-diacethylpyridine bis(salicylhydrazone) [H4DAPS], and various apical ligands in different charge states were synthesized: [Er(DAPMBH)(C2H5OH)Cl] (1); [Er(DAPMBH)(H2O)Cl]·2C2H5OH (2); [Er(DAPMBH)(CH3OH)Cl] (3); [Er(DAPMBH)(CH3OH)(N3)] (4); [(Et3H)N]+[Er(H2DAPS)Cl2]− (5); and [(Et3H)N]+[Y0.95Er0.05(H2DAPS)Cl2]− (6). The physicochemical properties, crystal structures, and the DC and AC magnetic properties of 1–6 were studied. The AC magnetic measurements revealed that most of Compounds 1–6 are field-induced single-molecule magnets, with estimated magnetization energy barriers, Ueff ≈ 16–28 K. The experimental study of the magnetic properties was complemented by theoretical analysis based on ab initio and crystal field calculations. An experimental and theoretical study of the magnetism of 1–6 shows the subtle impact of the type and charge state of the axial ligands on the SMM properties of these complexes. 相似文献