全文获取类型
收费全文 | 513篇 |
免费 | 20篇 |
国内免费 | 2篇 |
专业分类
化学 | 314篇 |
晶体学 | 3篇 |
力学 | 6篇 |
数学 | 69篇 |
物理学 | 143篇 |
出版年
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 14篇 |
2014年 | 9篇 |
2013年 | 28篇 |
2012年 | 12篇 |
2011年 | 17篇 |
2010年 | 13篇 |
2009年 | 14篇 |
2008年 | 18篇 |
2007年 | 16篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1993年 | 12篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 5篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1969年 | 7篇 |
1968年 | 7篇 |
1967年 | 4篇 |
1966年 | 5篇 |
1960年 | 4篇 |
排序方式: 共有535条查询结果,搜索用时 62 毫秒
441.
Turba S Walter O Schindler S Nielsen LP Hazell A J McKenzie C Lloret F Cano J Julve M 《Inorganic chemistry》2008,47(20):9612-9623
Copper(II) complexes of the ligand 1,n-bis[bis(2-pyridylmethyl)amino]benzene with n = 2-4 (1,n-tpbd) and its mononuclear derivative bis(2-pyridylmethyl)aniline (phbpa) were synthesized and structurally characterized. Magnetic measurements and DFT calculations were performed on [CuCl2(phbpa)], [Cu2Cl4(1,3-tpbd)], [(Cu2Cl2(ClO4)(1,3-tpbd))Cl(Cu2Cl2(OH2)(1,3-tpbd))](ClO4)2, and [Cu2(OH2)2(S2O6)(1,3-tpbd)]S2O6, and the exchange-polarization mechanism was successfully demonstrated. 相似文献
442.
443.
Masoud Amirkhani Nicola Berger Mohamed Abdelmohsen Frank Zocholl Manuel Rodrigues Gonçalves Othmar Marti 《Journal of Polymer Science.Polymer Physics》2011,49(20):1430-1436
The Breath‐Figure technique was employed to imprint honeycomb structures in the polymer films via the condensation of water vapor on the surface of an evaporating polymer solution. Generally, the condensed water droplets can be stabilized by an end‐functional polymer or by particles added to the polymer solution. In this study, we carried out a systematic experiment on the effect of different stabilizers on the porous honeycomb structure under identical physical conditions. The end‐functional polymer produced a large area of regular spherical bubbles, whereas adding particles to the polymer solution leads to smaller arrays of the flattened bottom bubbles. The separation length between pores was larger for polymer/particle sample than that of the end‐functional polymer films. In the regular area of polymer/particle film many bubbles were not decorated by particles. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1430–1436, 2011 相似文献
444.
Es wird über Methoden der Entwicklung und Herstellung von radioaktiven Referenzpräparaten berichtet, eine Reihe dieser Präparate schwer punktmäβig dargestellt und ihre Anwendung erläutert. 相似文献
445.
Diana Schindler Marika Felsmann Edwin Weber 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(7):o361-o363
Crystallization of 5,5′‐diphenyl‐2,2′‐(p‐phenylene)di‐1,3‐oxazole (POPOP), C24H16N2O2, from chloroform or 1,4‐dioxane yielded crystals in pure and solvated forms, respectively. The solvated crystals of POPOP were found to contain 1,4‐dioxane in a strict 1:2 compound–solvent stoichiometry, C24H16N2O2·C4H8O2, thus being a defined solvent‐inclusion compound. The crystal system is monoclinic in both cases and the asymmetric unit of the cell contains only half of the molecule (plus one dioxane molecule in the case of the solvated structure), owing to the centrosymmetry of the di‐1,3‐oxazole molecule. 相似文献
446.
Schindler A Heindl C Balázs G Gröger C Virovets AV Peresypkina EV Scheer M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(3):829-835
Treatment of the pentaphosphaferrocene [Cp*Fe(η5‐P5)] with CuI halides in the presence of different templates leads to novel fullerene‐like spherical molecules that serve as hosts for the templates. If ferrocene is used as the template the 80‐vertex ball [Cp2Fe]@[{Cp*Fe(η5‐P5)}12{CuCl}20] ( 4 ), with an overall icosahedral C80 topological symmetry, is obtained. This result shows the ability of ferrocene to compete successfully with the internal template of the reaction system [Cp*Fe(η5‐P5)], although the 90‐vertex ball [{Cp*Fe(η5:η1:η1:η1:η1:η1‐P5)}12(CuCl)10(Cu2Cl3)5{Cu(CH3CN)2}5] ( 2 a ) containing pentaphosphaferrocene as a guest is also formed as a byproduct. With use of the triple‐decker sandwich complex [(CpCr)2(μ,η5‐As5)] as a template the reaction between [Cp*Fe(η5‐P5)] and CuBr leads to the 90‐vertex ball [(CpCr)2(μ,η5‐As5)]@[{Cp*Fe(η5‐P5)}12{CuBr}10{Cu2Br3}5{Cu(CH3CN)2}5] ( 6 ), in which the complete molecule acts as a template. However, if the corresponding reaction is instead carried out with CuCl, cleavage of the triple‐decker complex is found and the 80‐vertex ball [CpCr(η5‐As5)]@[{Cp*Fe(η5‐P5)}12{CuCl}20] ( 5 ) is obtained. This accommodates as its guest [CpCr(η5‐As5)], which has only 16 valence electrons in a triplet ground state and is not known as a free molecule. The triple‐decker sandwich complex [(CpCr)2(μ,η5‐As5)] requires 53.1 kcal mol?1 to undergo cleavage (as calculated by DFT methods) and therefore this reaction is clearly endothermic. All new products have been characterized by single‐crystal X‐ray crystallography. A favoured orientation of the guest molecules inside the host cages has been identified, which shows π???π stacking of the five‐membered rings (Cp and cyclo‐As5) of the guests and the cyclo‐P5 rings of the nanoballs of the hosts. 相似文献
447.
The Drude oscillator model is applied to the molecular ionic liquid 1-ethyl-3-methyl-imidazolium triflate. The range of manageable Drude charges is tested. The strength of the polarizability is systematically varied from 0% to 100%. The influence on the structure, single particle dynamics, and collective dielectric properties is investigated. The generalized dielectric constant can be decomposed into a dielectric permittivity, a dielectric conductivity, and an optical dielectric constant ?(∞). The major part of the static generalized dielectric constant comes from the collective rotation of the ions, i.e., the dielectric permittivity. The translational contribution from the dielectric conductivity is about 58% of the dielectric permittivity. For the evaluation of the optical dielectric contribution, the computational dielectric theory was adapted to the case of heterogeneous polarizabilities. In case of 100% polarizability, it reaches a value of approximately 2. 相似文献
448.
Twerdowski E von Buttlar M Razek N Wannemacher R Schindler A Grill W 《Ultrasonics》2006,44(Z1):e1301-e1305
Employment of ultrasound techniques in nondestructive testing may require identification of the acoustic modes contributing to imaging. Such identification can be achieved, with some restrictions, by time-of-flight analysis. Another approach is acoustic holography that reveals the propagation properties of any selected mode. In anisotropic media, the propagation features are distinct and allow for a reliable classification of the selected mode. Both techniques were applied for classification of bonded, disbonded, and weakly bonded areas in directly bonded semiconductor wafers. 相似文献
449.
Application of a line-shaped point spread function (PSF) to imaging of void defects in directly bonded wafers is considered. Two non-confocally adjusted spherical transducers are employed to implement an acoustic microscope operating in transmission with a time dependent point spread function, whose shape is optimized by both temporal apodization of the received signal and spatial apodization of the transducer aperture. Strong imaging artifacts resulting from the generation and detection of edge waves are eliminated in this way. It is shown by several examples that only a broadband system can be utilized in order to obtain a line-shaped PSF suitable for imaging. 相似文献
450.