全文获取类型
收费全文 | 196篇 |
免费 | 12篇 |
专业分类
化学 | 150篇 |
力学 | 1篇 |
数学 | 42篇 |
物理学 | 15篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 7篇 |
2018年 | 1篇 |
2017年 | 6篇 |
2016年 | 4篇 |
2015年 | 9篇 |
2014年 | 4篇 |
2013年 | 8篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 13篇 |
2007年 | 17篇 |
2006年 | 15篇 |
2005年 | 17篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 1篇 |
2001年 | 5篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1964年 | 1篇 |
1955年 | 1篇 |
1948年 | 3篇 |
排序方式: 共有208条查询结果,搜索用时 17 毫秒
61.
Fast-atom-bombardment mass spectra of ten phloroglucinol derivatives containing two to six ring units were recorded. The mass spectral behavior of the compounds was quite similar under these conditions. Molecular-weight information was readily available as well as sequential structural data due to extensive fragmentation. Sequential alterations due to the rottlerone change or other analogous decomposition reactions proved to be almost lacking in fast-atom-bombardment mass spectrometry. The negative-ion spectra in general showed better signal-to-noise ratios and more distinct fragment ions. 相似文献
62.
Marina Dudkina Vladimir Aseev Andrey Tenkovtsev Heikki Tenhu 《Journal of Polymer Science.Polymer Physics》2005,43(4):398-404
Interactions of phenolic and carboxylic groups containing chromophores (hydroxyarylidene alkanones) with polyamidines were investigated with ultraviolet–visible spectroscopy and dynamic light scattering experiments. Because of the strong basicity of the polyamidines, deprotonation of the chromophores was observed. The ionic network formation process depended on the method of the complex preparation. The step‐by‐step addition of the chromophore to an excess of polyamidine led to the incorporation of the dye molecules inside the polymer coil, and only after this did the interaction of surface functional groups with an additional amount of the low‐molecular‐weight compound lead to network formation. The interaction of the polymer with an excess of the dye initially led to the saturation of amidine groups by chromophore molecules and network formation without the complete destruction of the dye packs. The molecular structure proposed for these complexes was examined with experimental data. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 398–404, 2005 相似文献
63.
We introduce a Cooper pair "sluice" for the implementation of a frequency-locked current source. The device consists of two mesoscopic SQUIDs and of a single superconducting island with a gate. We demonstrate theoretically that it is possible to obtain a current as high as 0.1 nA at better than ppm accuracy via periodically modulating both the gate charge and the effective Josephson coupling. We find that the device is tolerant against background charge noise and operates well even in a dissipative environment. The effect of the imperfect suppression of the Josephson coupling and the finite operating frequency are also investigated. 相似文献
64.
65.
Heikki Joela 《Theoretical chemistry accounts》1975,39(3):241-246
A model of new submolecules is presented. As an application some absorptions of aromatic radicals are interpreted in UV and visible spectra. Extension of the model to biological systems is prejudged. 相似文献
66.
67.
In this paper we study the solutions of the equation $$\Delta w- \frac{\alpha}{y}\partial_{y}w = 0,$$ where w is a complex valued function. This equation is related to the generalized axially symmetric potential theory which has been studied notably by Weinstein, see [12]. We have researched this equation earlier in higher dimensions in connection with the hyperbolic function theory. In this paper will see how this equation is related to the generalized analytic functions in the hyperbolic upper half-plane. We also study harmonic differential forms in the hyperbolic plane and using these we obtain special type of solutions for the preceding equation. 相似文献
68.
We study a hyperbolic version of holomorphic functions to higher dimensions. In this frame work, a generalization of holomorphic functions are called \(k\)-hypermonogenic functions. These functions are depending on several real variables and their values are in a Clifford algebra. They are defined in terms of hyperbolic Dirac operators. They are connected to harmonic functions with respect to the Riemannian metric \(ds^{2}_k=x_{n}^{2k/\left( 1-n\right) }\left( dx_{0}^{2}+\cdots +dx_{n}^{2}\right) \) in the same way as the usual harmonic function to holomorphic functions. We present the mean value property for \(k\)-hypermonogenic functions and related results. Earlier the mean value properties has been proved for hypermonogenic functions. The key tools are the invariance properties of the hyperbolic metric. 相似文献
69.
70.