全文获取类型
收费全文 | 169篇 |
免费 | 11篇 |
国内免费 | 3篇 |
专业分类
化学 | 98篇 |
力学 | 6篇 |
数学 | 50篇 |
物理学 | 29篇 |
出版年
2023年 | 1篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 2篇 |
2014年 | 8篇 |
2013年 | 15篇 |
2012年 | 10篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 10篇 |
2008年 | 17篇 |
2007年 | 13篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1980年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有183条查询结果,搜索用时 359 毫秒
111.
Electron-transfer properties of different carbon nanotube materials,and their use in glucose biosensors 总被引:1,自引:0,他引:1
Different types of carbon nanotube material (single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs)
of different internal diameter) have been used for preparation of CNT-modified glassy-carbon electrodes. Redox reactions involving
ferricyanide and hydrogen peroxide were examined at the CNT-modified electrodes. Electrodes modified with SWCNTs usually had
better electron-transfer properties than MWCNT-modified electrodes. Glucose biosensors were also prepared with electropolymerized
polyphenylenediamine films, CNT materials, and glucose oxidase. Amperometric behavior in glucose determination was examined.
SWCNT-modified glucose biosensors usually had a wider dynamic range (from 0.1 to 5.5 mmol L−1) and greater sensitivity in glucose determination. The detection limit was estimated to be 0.05 mmol L−1. 相似文献
112.
Isotope effects in the reaction of hydroxyl radical with methane are investigated in a crossed-beam experiment. By exploiting different combinations of OH/OD + CH4/CD4/CHD3, a total of eight isotopically variant reactions are examined to decipher the dynamical consequence of both primary and secondary isotope effects. The most prominent observation is from isotopic substitution of the transferred atom (primary isotope effect), which yields more stretch-excited water product for the D atom case than H atom. The opposite is found, however, for excitations in bending and combination modes. The secondary isotope effects, from either substituted hydroxyl radical or the three H atoms that are not being abstracted, are relatively minor and manifest themselves in spreading the vibrational distribution of the water coproducts. 相似文献
113.
A general equation is derived for the shift in half wave potential, ΔE
, for ligand reduction on complexation with a metal. The formation of several complexes with differing stoichiometry and protonation states is considered explicitly. The dependence of ΔE
on metal ion concentration, holding the ligand concentration constant, can be used to determine stability constants or their ratios. The meaning of ΔE
depends on the stoichiometric changes following ligand oxidation state change, in a manner analogous to the case where the metal is the redox site. 相似文献
114.
115.
Khoshnevisan Davar Kim Kunwoo Mueller Carl Shiu Shang-Yuan 《Journal of statistical physics》2020,179(2):502-534
Journal of Statistical Physics - The study of intermittency for the parabolic Anderson problem usually focuses on the moments of the solution which can describe the high peaks in the probability... 相似文献
116.
The product pair correlation of the title reaction was measured with rotational selection for both the vibrationally ground CD3(nu = 0) and umbrella-excited CD3(nu2 = 2) products. A striking linear relationship was found between the rotational energy of the selected CD3 product and the correlated kinetic energy release (or the average vibrational energy of the DF coproduct). Such a linearly correlated (or anticorrelated) dependence appears to be stronger for CD3(nu2 = 2,N) than for CD3(nu = 0,N). The mechanistic implication of the observation is that the rotational motion N of the CD3 product tends to lie antiparallel to the orbital angular momentum l' of the two departing products. The dependency on the K quantum number--the projection of N on the top axis--is, on the other hand, less significant yet noticeable. 相似文献
117.
118.
The vertex arboricity of a graph is the minimum number of colors the vertices can be labeled so that each color class induces a forest. It was well-known that for every planar graph . In this paper, we prove that if is a planar graph without 7-cycles. This extends a result in [A. Raspaud, W. Wang, On the vertex-arboricity of planar graphs, European J. Combin. 29 (2008) 1064–1075] that for each , planar graphs without -cycles have . 相似文献
119.
The paper studies a discrete counterpart of Gerber et al. (2006). The surplus of an insurance company (before dividends) is modeled as a time-homogeneous Markov chain with possible changes of size +1,0,−1,−2,−3,…. If a barrier strategy is applied for paying dividends, it is shown that the dividends-penalty identity holds. The identity expresses the expected present value of a penalty at ruin in terms of the expected discounted dividends until ruin and the expected present value of the penalty at ruin if no dividends are paid. For the problem of maximizing the difference between the expected discounted dividends until ruin and the expected present value of the penalty at ruin, barrier strategies play a prominent role. In some cases an optimal dividend barrier exists. The paper discusses in detail the special case where the distribution of the change in surplus does not depend on the current surplus (so that in the absence of dividends the surplus process has independent increments). A closed-form result for zero initial surplus is given, and it is shown how the relevant quantities can be calculated recursively. Finally, it is shown how optimal dividend strategies can be determined; typically, they are band strategies. 相似文献
120.
The title reaction was investigated under crossed-beam conditions at three different collision energies, E(c) = 8.4, 2.76 and 1.46 kcal mol(-1). The combination of using a (2 + 1) resonance-enhanced multiphoton ionization for tagging state-specific CD(3) products and exploiting a time-sliced velocity imaging for ion detection allows us to reveal the coincident information of the two product pairs in a state-correlated manner. The pair-correlated results are reported for the two product vibrators -- (v(2) = 0, v'), (v(2) = 1, v'), (v(2) = 2, v') and (v(2) = 3, v')-and the dynamics attributes we examined include product state distributions, energy disposals and angular distributions. Together with our earlier communications, a rather complete picture of the correlated dynamics of the title reaction emerges. One of the major findings, the anti-correlated excitations of the two product vibrators at all four energies of this study, can qualitatively be understood by kinematics arguments. 相似文献