全文获取类型
收费全文 | 89篇 |
免费 | 1篇 |
专业分类
化学 | 44篇 |
力学 | 1篇 |
数学 | 15篇 |
物理学 | 30篇 |
出版年
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 1篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 4篇 |
2012年 | 2篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 9篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1979年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有90条查询结果,搜索用时 31 毫秒
21.
Geraldine A. Torín-Ollarves José J. Segovia M. Carmen Martín Miguel A. Villamañán 《The Journal of chemical thermodynamics》2012,44(1):75-83
The densities at high pressures of 1-butanol and iso-octane were measured in the range (0.1 to 140) MPa at seven different temperatures, from (273.15 to 333.15) K, and their mixtures were measured in the range (0.1 to 50) MPa at four different temperatures, from (273.15 to 333.15) K. The measurements were performed in a high-pressure vibrating tube densimeter. The pressure–volume–temperature behavior of these compounds and their mixtures was evaluated accurately over a wide range of temperatures and pressures. The data were successfully correlated with the empirical Tamman–Tait equation. The experimental data and the correlations were used to study the behavior and the influence of temperature and pressure on the isothermal compressibility and the isobaric thermal expansivity.Also, the isobaric heat capacities were measured over the range (0.1 to 25) MPa at two different temperatures (293.15 and 313.15) K for the pure compounds and their mixtures. The measurements were performed in a high-pressure automated flow calorimeter. The excess molar heat capacities were assessed for the mixture and a positive deviation from the ideality was obtained. 相似文献
22.
23.
In this article we develop the theory of one-sided versions of the g function of Littlewood and Paley, the area function S of Lusin and the\(g_\lambda ^* \) that admit weighted norm estimates with weights belonging to the classes A p + of Sawyer. In Sections 1 and 2 we give definitions and some lemmas that shall be needed. Section 3 is devoted to the study of the one-sided version of the functions g and S. In Section 4 we obtain a good λ estimate for the one-sided\(g_\lambda ^* \) function, and in Sections 5 and 6 we apply the results already obtained to fractional integrals and multiplier operators. 相似文献
24.
I. Abu-Falahah R. A. Macías C. Segovia J. L. Torrea 《Proceedings Mathematical Sciences》2009,119(2):203-220
Given the family of Laguerre polynomials, it is known that several orthonormal systems of Laguerre functions can be considered.
In this paper we prove that an exhaustive knowledge of the boundedness in weighted L
p
of the heat and Poisson semigroups, Riesz transforms and g-functions associated to a particular Laguerre orthonormal system of functions, implies a complete knowledge of the boundedness
of the corresponding operators on the other Laguerre orthonormal system of functions. As a byproduct, new weighted L
p
boundedness are obtained. The method also allows us to get new weighted estimates for operators related with Laguerre polynomials.
Carlos Segovia passed away on April 3, 2007. 相似文献
25.
James D. Grayson Matthew P. Baumgartner Cleide Dos Santos Souza Samuel J. Dawes Imane Ghafir El Idrissi Jennifer C. Louth Sasha Stimpson Emma Mead Charlotte Dunbar Joanna Wolak Gary Sharman David Evans Anastasia Zhuravleva Margarita Segovia Roldan Nicola Antonio Colabufo Ke Ning Claire Garwood James A. Thomas Benjamin M. Partridge Antonio de la Vega de Leon Valerie J. Gillet Amlia P. Rauter Beining Chen 《Chemical science》2021,12(10):3768
Amyloid β oligomers (Aβo) are the main toxic species in Alzheimer''s disease, which have been targeted for single drug treatment with very little success. In this work we report a new approach for identifying functional Aβo binding compounds. A tailored library of 971 fluorine containing compounds was selected by a computational method, developed to generate molecular diversity. These compounds were screened for Aβo binding by a combined 19F and STD NMR technique. Six hits were evaluated in three parallel biochemical and functional assays. Two compounds disrupted Aβo binding to its receptor PrPC in HEK293 cells. They reduced the pFyn levels triggered by Aβo treatment in neuroprogenitor cells derived from human induced pluripotent stem cells (hiPSC). Inhibitory effects on pTau production in cortical neurons derived from hiPSC were also observed. These drug-like compounds connect three of the pillars in Alzheimer''s disease pathology, i.e. prion, Aβ and Tau, affecting three different pathways through specific binding to Aβo and are, indeed, promising candidates for further development.A new approach combining virtual screening, 19F and STD NMR, and biochemical assays using hiPSC and targetting multiple pathways involving Aβ, PrPC and Tau provides a more effective strategy for Alzheimer''s disease drug discovery than Aβ only approach. 相似文献
26.
27.
Soil radon behavior related to the volcanic eruptive period 1997–1999 of Popocatepetl volcano has been studied as a function of the volcanic activity. Since the volcano is located 60 km from Mexico City, the risk associated with an explosive eruptive phase is high and an intense surveillance program has been implemented. Previous studies in this particular volcano showed soil radon pulses preceding the initial phase of the eruption. The radon survey was performed with LR-115 track detectors at a shallow depth and the effect of the soil moisture during the rainy season has been observed on the detectors response. In the present state of the volcanic activity the soil radon behavior has shown more stability than in previous eruptive stages. 相似文献
28.
Cecilio Mar-Molinero Diego Prior Maria-Manuela Segovia Fabiola Portillo 《Annals of Operations Research》2014,221(1):273-283
The standard DEA model allows different DMU units to set their own priorities for the inputs and outputs that form part of the efficiency assessment. In the case of a centralized organization with many outlets, such as an education authority that is responsible for many schools, it may be more sensible to operate in the most efficient way, but under a common set of priorities for all DMUs. The algorithm that is used to do this, the centralized resource allocation model, does just this. We show that the centralized resource allocation model can be substantially simplified and we interpret the simplifications and show how the model works using real data of Spanish public schools. Apart from finding the best way to reallocate resource among the schools, it is shown that the most desirable operating unit is found to be a by-product of the estimation. This is useful information when planning new schools. 相似文献
29.
In this work, we study the competence between the reactions of hydrogen and methyl scission during thermal cracking and combustion of propane, the emergence of the two isomers of the propyl radical, n-propyl and i-propyl, and their subsequent ??-scission reaction to ethene and methyl radical. The purpose of the study was to analyze the accuracy of density functional (DFT) methods as applied on this relatively well-known subset of the reactions implied in the production of propylene oxide from propane and propene. Conventional (B3LYP, B3PW91) and state-of-the-art (PBE0, M06, BMK) DFT methods were employed, and their accuracy checked against experimental data and calculations performed using model chemistries (complete basis set CBS-4M, QB3, and APNO, and G4 methods) and ab initio methods (MP2, CCSD(T) with a large 6-311 ++G(3df,2pd) basis set). The results obtained at the BMK level for the thermodynamics of the reactions are closer to experimental data than those afforded by any other DFT method and very similar actually to CBS or CCSD(T) results, even if a medium size basis set is used. Activation energies determined using two- and three-parameter Arrhenius equations are also very good, but the preexponential factors are incorrect. Tunneling and internal rotation corrections must be applied to obtain semiquantitative results. 相似文献
30.