全文获取类型
收费全文 | 1199篇 |
免费 | 53篇 |
国内免费 | 2篇 |
专业分类
化学 | 703篇 |
晶体学 | 2篇 |
力学 | 65篇 |
数学 | 207篇 |
物理学 | 277篇 |
出版年
2024年 | 1篇 |
2023年 | 15篇 |
2022年 | 62篇 |
2021年 | 59篇 |
2020年 | 42篇 |
2019年 | 52篇 |
2018年 | 41篇 |
2017年 | 28篇 |
2016年 | 66篇 |
2015年 | 58篇 |
2014年 | 36篇 |
2013年 | 78篇 |
2012年 | 101篇 |
2011年 | 112篇 |
2010年 | 50篇 |
2009年 | 34篇 |
2008年 | 66篇 |
2007年 | 66篇 |
2006年 | 72篇 |
2005年 | 47篇 |
2004年 | 45篇 |
2003年 | 44篇 |
2002年 | 19篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1932年 | 1篇 |
1912年 | 1篇 |
1903年 | 1篇 |
1877年 | 1篇 |
排序方式: 共有1254条查询结果,搜索用时 0 毫秒
91.
Benati L Leardini R Minozzi M Nanni D Spagnolo P Strazzari S Zanardi G 《Organic letters》2002,4(18):3079-3081
[reaction: see text] Aryl- and alkyl-derived azidoacyl radicals, generated from thiolesters by intramolecular homolytic substitution at the sulfur, can undergo five- and six-membered cyclization onto the azido moiety to give cyclized lactams. 相似文献
92.
A series of cyano-bridged binuclear mixed valence complexes of the general formula M-Ru(III)(NH(3))(4)pyCOOH [pyCOOH = isonicotinic acid; M = cis-Ru(bpy)(2)(CN)(2), 1 (bpy = 2,2' bipyridine); trans-Ru(py)(4)(CN)(2), 2 (py = pyridine); [Ru(CN)(6)](4)(-), 3; [Fe(CN)(6)](4)(-), 4] have been prepared and anchored through the carboxylic function to nanocrystalline TiO(2) or SnO(2) electrodes. The complexes display a reversible electrochromic behavior in the range of applied potential from -0.5 to +0.5 V, versus SCE. Tuning of the electronic transitions in the visible and near-infrared spectral regions is achieved through changes of the solvent and of the cyano-bridged metal moiety M. 相似文献
93.
94.
95.
Antonio Degasperis Matteo Conforti Fabio Baronio Stefan Wabnitz Sara Lombardo 《Letters in Mathematical Physics》2011,96(1-3):367-403
The spectral theory of the integrable partial differential equations which model the resonant interaction of three waves is considered with the purpose of numerically solving the direct spectral problem for both vanishing and non vanishing boundary values. Methods of computing both the continuum spectrum data and the discrete spectrum eigenvalues are given together with examples of such computations. The explicit spectral representation of the Manley-Rowe invariants is also displayed. 相似文献
96.
Barbara Bianconi Matteo Focardi Elvira Mascolo 《Annali di Matematica Pura ed Applicata》2002,180(4):493-510
We study the lower semicontinuity properties of non-autonomous variational integrals whose energy densities satisfy general
growth conditions. We apply these results to solve Dirichlet’s boundary value problems for such functionals.
Received: June 14, 2000; in final form: November 25, 2000 Published online: December 19, 2001 相似文献
97.
The effect of the angular momentum density of a gravitational source on the times of flight of light rays in an interferometer is analyzed. The calculation is made imagining that the interferometer is at the equator of an axisymmetric steadily rotating gravity source. In order to evaluate the size of the effect in the case of the Earth a weak field approximation for the metric elements is introduced. For laboratory scales and non-geodesic paths the correction due to the angular momentum turns out to be comparable with the sensitivity expected in gravitational waves interferometric detectors, whereas it drops under the threshold of detectability when using free (geodesic) light rays. 相似文献
98.
99.
Selective reagent ionisation‐time of flight‐mass spectrometry: a rapid technology for the novel analysis of blends of new psychoactive substances 下载免费PDF全文
Matteo Lanza W. Joe Acton Philipp Sulzer Kostiantyn Breiev Simone Jürschik Alfons Jordan Eugen Hartungen Gernot Hanel Lukas Märk Tilmann D. Märk Chris A. Mayhew 《Journal of mass spectrometry : JMS》2015,50(2):427-431
In this study we demonstrate the potential of selective reagent ionisation‐time of flight‐mass spectrometry for the rapid and selective identification of a popular new psychoactive substance blend called ‘synthacaine’, a mixture that is supposed to imitate the sensory and intoxicating effects of cocaine. Reactions with H3O+ result in protonated parent molecules which can be tentatively assigned to benzocaine and methiopropamine. However, by comparing the product ion branching ratios obtained at two reduced electric field values (90 and 170 Td) for two reagent ions (H3O+ and NO+) to those of the pure chemicals, we show that identification is possible with a much higher level of confidence then when relying solely on the m/z of protonated parent molecules. A rapid and highly selective analytical identification of the constituents of a recreational drug is particularly crucial to medical personnel for the prompt medical treatment of overdoses, toxic effects or allergic reactions. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
100.
Bibienne Thomas Maillaud Laurent Rousselot Steeve Taylor Lauren W. Pasquali Matteo Dollé Mickaël 《Journal of Solid State Electrochemistry》2017,21(5):1407-1416
Journal of Solid State Electrochemistry - The preparation of collector- and binder-free, high-energy density cathodes made from carbon-coated LiFePO4 (C-LFP) and single-walled carbon nanotubes... 相似文献