全文获取类型
收费全文 | 96篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
化学 | 57篇 |
力学 | 2篇 |
数学 | 32篇 |
物理学 | 6篇 |
出版年
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 7篇 |
2006年 | 3篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1958年 | 1篇 |
1905年 | 1篇 |
排序方式: 共有97条查询结果,搜索用时 15 毫秒
31.
32.
Katia Liburdi Raffaello Straniero Ilaria Benucci Anna Maria Vittoria Garzillo Marco Esti 《Applied biochemistry and biotechnology》2012,166(7):1736-1746
In order to use lysozyme as an anti-microbial agent during the winemaking process, hen egg-white lysozyme (LYZ) was covalently
immobilized on two different micro-size magnetic particles (tosyl-activated and carboxylated, TSA and CA, respectively). A
cell suspension of Oenococcus oeni, an oenological strain involved in the winemaking process, was utilized as LYZ substrate. Both a kinetic study and a study
of the stability of free and immobilized LYZ were performed in McIlvane buffer at pH 3.2, that is the average minimum pH value
in wine. The activity and kinetic parameters measured for the free LYZ at pH 3.2 are lower than those reported at the optimum
pH (4.5); however the residual activity at pH 3.2 is sufficient to be of interest for further immobilization and applications
in winemaking. All kinetic parameters of both biocatalysts (LYZ-CA and LYZ-TSA) are altered after immobilization, probably
due to the structural modifications in the active site caused by covalent attachment to the supports. The half-life calculated
at 25 °C was 39 h for free LYZ, while it increased to 280 and 134 h for LYZ-TSA and LYZ-CA, respectively. This result indicates
that immobilization improves the enzyme stability and that LYZ can be utilized in wine applications in its immobilized forms.
In addition, LYZ-TSA seems to be the best biocatalyst for further applications in winemaking. 相似文献
33.
34.
A recent comparison result ([3]) allows to get pointwise estimates for the solution of the Dirichlet problem for linear second–order elliptic equations in terms of the solution of a suitable "symmetrized" problem. In this paper we prove that equality is achieved only in the spherically symmetric situation. 相似文献
35.
Quantifying uniformity of a configuration of points on the sphere is an interesting topic that is receiving growing attention in numerical analysis. An elegant solution has been provided by Cui and Freeden [J. Cui, W. Freeden, Equidistribution on the sphere, SIAM J. Sci. Comput. 18 (2) (1997) 595–609], where a class of discrepancies, called generalized discrepancies and originally associated with pseudodifferential operators on the unit sphere in R3, has been introduced. The objective of this paper is to extend to the sphere of arbitrary dimension this class of discrepancies and to study their numerical properties. First we show that generalized discrepancies are diaphonies on the hypersphere. This allows us to completely characterize the sequences of points for which convergence to zero of these discrepancies takes place. Then we discuss the worst-case error of quadrature rules and we derive a result on tractability of multivariate integration on the hypersphere. At last we provide several versions of Koksma–Hlawka type inequalities for integration of functions defined on the sphere. 相似文献
36.
We investigate the use of the Hurst exponent, dynamically computed over a weighted moving time-window, to evaluate the level of stability/instability of financial firms. Financial firms bailed-out as a consequence of the 2007–2008 credit crisis show a neat increase with time of the generalized Hurst exponent in the period preceding the unfolding of the crisis. Conversely, firms belonging to other market sectors, which suffered the least throughout the crisis, show opposite behaviors. We find that the multifractality of the bailed-out firms increase at the crisis suggesting that the multi fractal properties of the time series are changing. These findings suggest the possibility of using the scaling behavior as a tool to track the level of stability of a firm. In this paper, we introduce a method to compute the generalized Hurst exponent which assigns larger weights to more recent events with respect to older ones. In this way large fluctuations in the remote past are less likely to influence the recent past. We also investigate the scaling associated with the tails of the log-returns distributions and compare this scaling with the scaling associated with the Hurst exponent, observing that the processes underlying the price dynamics of these firms are truly multi-scaling. 相似文献
37.
It is known that, if u is a real valued function on ?N of bounded variation, then its total variation decreases under polarization. In this paper we identify the difference between the total variation of u and that one of its polar uΠ (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
38.
Raffaello Fusco Alessandro Marchesini Franco Sannicol 《Journal of heterocyclic chemistry》1986,23(6):1795-1799
Arylazoanils carrying aromatic methyl or ethyl groups in the position ortho to the imine function thermally cyclize to give 1H-4,5-dihydro-1,3,4-benzotriazepine derivatives in fairly good yields. A study of the effect of the substituents on both the aryl rings is reported. The reaction is interpreted as an internal oxo-reduction process. 相似文献
39.
Moser-type estimates for functions whose gradient is in the Lorentz space L(n, q), 1q, are given. Similar results are obtained for solutions uH
inf0
sup1
of Au=(f
i
)
x
i
, where A is a linear elliptic second order differential operator and |f|L(n, q), 2q.Work partially supported by MURST (40%). 相似文献
40.
Paolo Pertici Giovanni Vitulli Clara Bigelli Raffaello Lazzaroni 《Journal of organometallic chemistry》1984,275(1):113-117
Ru(η6-arene)(η4-COD) complexes (COD = cycloocta-1,5-diene) have been found to be catalytic precursors for the homogeneous hydrogenation of α-olefins and cycloolefins under mild conditions (room temperature, P(H2) 1–20 atm). 相似文献