全文获取类型
收费全文 | 707篇 |
免费 | 45篇 |
国内免费 | 3篇 |
专业分类
化学 | 505篇 |
晶体学 | 8篇 |
力学 | 17篇 |
数学 | 108篇 |
物理学 | 117篇 |
出版年
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 25篇 |
2019年 | 13篇 |
2018年 | 6篇 |
2017年 | 11篇 |
2016年 | 20篇 |
2015年 | 22篇 |
2014年 | 20篇 |
2013年 | 31篇 |
2012年 | 60篇 |
2011年 | 58篇 |
2010年 | 44篇 |
2009年 | 21篇 |
2008年 | 59篇 |
2007年 | 44篇 |
2006年 | 38篇 |
2005年 | 34篇 |
2004年 | 23篇 |
2003年 | 18篇 |
2002年 | 18篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 7篇 |
1939年 | 3篇 |
1924年 | 2篇 |
排序方式: 共有755条查询结果,搜索用时 156 毫秒
41.
42.
43.
Ludovic Leymarie Jérôme Dupuy Estelle Villegas Philippe Chaumont Nathalie Sintes‐Zydowicz Etienne Fleury 《Journal of polymer science. Part A, Polymer chemistry》2012,50(19):4145-4154
Novel oligodimethylsiloxane‐based polymers with alkyl side chain were synthesized in bulk by step‐growth polymerization between α,ω‐glycidyl ether oligodimethylsiloxanes and a monoalkylamine in the absence of catalyst and at temperatures ranging between 80 and 180 °C. Matrix assisted laser desorption ionization time of flight results attested for the high reactivity of the amine functions with the glycidyl groups and revealed that the main polymer structure was (A2B2)n type with alkyl moieties as dangling chains. No etherification was observed during the reaction even at high temperatures and the nature of the end groups strongly depended on the molar ratio between glycidyl and amine functions. Polymerization reactions were followed by 1H NMR and the kinetics of the glycidyl‐amine reaction pointed out the dependence of temperature, molar ratio, and the molar mass of the oligodimethylsiloxane. High conversion rates were obtained, especially with the lowest molecular weight oligodimethylsiloxane. An optimized kinetic model derived from the Horie's model was discussed and permitted to correctly fit the experimental data. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
44.
Sorin‐Claudiu Roşca Dr. Chiara Dinoi Dr. Elsa Caytan Dr. Vincent Dorcet Prof. Dr. Michel Etienne Prof. Dr. Jean‐François Carpentier Dr. Yann Sarazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6505-6509
Strontium and calcium (alkaline earth: Ae) olefin complexes stabilised by secondary Ae???F?C and β‐agostic Ae???H?Si interactions are presented. Olefin coordination onto the alkaline earths is plain in the solid state, and it is thermodynamically favoured over the coordination of THF. The existence of the Ae???olefin interactions is corroborated by solution NMR data and DFT computations. The coordination mode of the olefin varies with steric effects and, if enforced, olefin dissociation can be compensated by the other non‐covalent interactions, as supported by DFT computations. 相似文献
45.
46.
47.
Couturier M Ménard F Ragan JA Riou M Dauphin E Andresen BM Ghosh A Dupont-Gaudet K Girardin M 《Organic letters》2004,6(11):1857-1860
Lewis-base-catalyzed cycloisomerization of bis(enones) to decalins has been demonstrated as an alternative to the traditional Lewis acid catalyzed Diels-Alder cycloaddition. In this process, a trialkylphosphine mediates both bond formation steps in two distinct catalytic cycles. The single-pot operation generates two carbon-carbon bonds and up to five contiguous stereocenters in one step, starting from achiral, aliphatic substrates; eight examples are provided. [reaction: see text] 相似文献
48.
Alain Tressaud Etienne Durand Christine Labrugère 《Journal of fluorine chemistry》2004,125(11):1639-1648
Due to their extreme reactivity, fluorine and fluorinated gases may be used to modify the surface properties of numerous materials. In the following, the surface fluorination of some carbon-based compounds (graphite, graphitised carbon fibres, carbon blacks and elastomers) using CF4 rf plasma technique and direct F2-gas fluorination is proposed. From XPS studies, the different types of CF bonding obtained in the materials after treatment have been correlated either to the physico-chemical characteristics of the pristine material or to the experimental parameters of the fluorination. Reaction mechanisms are proposed. 相似文献
49.
Menard E Bilhaut L Zaumseil J Rogers JA 《Langmuir : the ACS journal of surfaces and colloids》2004,20(16):6871-6878
Nanotransfer printing represents an additive approach for patterning thin layers of solid materials with nanometer resolution. The surface chemistries, thin film deposition techniques, and stamp designs are all important for the proper operation of this method. This paper presents some details concerning processing procedures and other considerations needed for patterning two- and three-dimensional nanostructures with low density of defects and minimal distortions. 相似文献
50.
Hawthorn DG Hill RW Proust C Ronning F Sutherland M Boaknin E Lupien C Tanatar MA Paglione J Wakimoto S Zhang H Taillefer L Kimura T Nohara M Takagi H Hussey NE 《Physical review letters》2003,90(19):197004
The transport of heat and charge in cuprates was measured in single crystals of La(2-x)Sr(x)CuO(4+delta) (LSCO) across the doping phase diagram at low temperatures. In underdoped LSCO, the thermal conductivity is found to decrease with increasing magnetic field in the T-->0 limit, in striking contrast to the increase observed in all superconductors, including cuprates at higher doping. In heavily underdoped LSCO, where superconductivity can be entirely suppressed with an applied magnetic field, we show that a novel thermal metal-to-insulator transition takes place upon going from the superconducting state to the field-induced normal state. 相似文献