全文获取类型
收费全文 | 105篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
化学 | 46篇 |
数学 | 40篇 |
物理学 | 26篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 10篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 1篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 8篇 |
1971年 | 3篇 |
1968年 | 1篇 |
排序方式: 共有112条查询结果,搜索用时 15 毫秒
101.
The first syntheses of chiral 3- and 2-vinylindoles bearing sulfoxide or (-)-menthyloxy functional groups at the β-vinyl positions by way of procedures based on the Horner-Wadsworth-Emmons and Wittig reactions, respectively, are described. Some Diels-Alder reactions demonstrating the 4π-reactivity of these compounds are reported. 相似文献
102.
Let Xn, n
, be i.i.d. with mean 0, variance 1, and E(¦Xn¦r) < ∞ for some r 3. Assume that Cramér's condition is fulfilled. We prove that the conditional probabilities P(1/√n Σi = 1n Xi t¦B) can be approximated by a modified Edgeworth expansion up to order o(1/n(r − 2)/2)), if the distances of the set B from the σ-fields σ(X1, …, Xn) are of order O(1/n(r − 2)/2)(lg n)β), where β < −(r − 2)/2 for r
and β < −r/2 for r
. An example shows that if we replace β < −(r − 2)/2 by β = −(r − 2)/2 for r
(β < −r/2 by β = −r/2 for r
) we can only obtain the approximation order O(1/n(r − 2)/2)) for r
(O(lg lgn/n(r − 2)/2)) for r
). 相似文献
103.
We prove for random variables with values in the space of cadlag functions - endowed with the supremum metric - that convergence in law is equivalent to nonstandard constructions of internal -cadlag processes, which represent up to an infinitesimal error the limit process. It is not required that the limit process is concentrated on the space , so that the theory is applicable to a wider class of limit processes as e.g. to Poisson processes or Gaussian processes. If we consider in the Skorokhod metric - instead of the supremum metric - we obtain a corresponding equivalence to constructions of internal processes with -separated jumps. We apply these results to functional central limit theorems.
104.
1,1-Bis(dimethylamino)-1,3-butadiene ( 1 ) as a strong donor diene (E1/2 = 0.03 V vs. SCE, 1st IPv = 6.94 eV) is treated with acrylonitrile, dimethyl dicyanofumarate, and tetracyanoethylene. Cycloaddition with acrylonitrile is slow and requires elevated temperatures at which elimination of dimethylamine with formation of 1-cyano-2-(dimethylamino)-1,3-cyclohexadiene occurs. The reaction of 1 with TCNE at −40°C in acetonitrile is very fast and leads to the zwitterion 5 . At T ⩾ −20°C, 5 eliminates hydrogen cyanide to give a highly colored (λmax = 489 nm, lgϵ = 4.716) merocyanine. A zwitterion 9 generated from 1 and dimethyl dicyanofumarate can be isolated in crystalline form. The structural analysis shows that the zwitterions are produced by attack of the olefin at the antiperiplanar conformation of 1 . Both zwitterions which can be trapped as crystalline picrates cannot be converted to cycloadducts. These results suggest that cycloaddition is observed if zwitterion formation becomes energetically unfavorable. 相似文献
105.
In this paper we investigate the connection between the range of nearest point projections in Lp -spaces and monotony properties of the projection operator. We show e.g. that a nearest point projection onto a closed convex subset of an Lp -space (1
相似文献
106.
L Cherchye W Moesen N Rogge T Van Puyenbroeck M Saisana A Saltelli R Liska S Tarantola 《The Journal of the Operational Research Society》2008,59(2):239-251
Composite indicators (CIs) are often used for benchmarking countries' performance, but they frequently stir controversies about the unavoidable subjectivity in their construction. Data Envelopment Analysis helps to overcome some key limitations, as it does not need any prior information on either the normalization of sub-indicators or on an agreed unique set of weights. Still, subjective decisions remain, and such modelling uncertainty propagates onto countries' CI scores and rankings. Uncertainty and sensitivity analysis are therefore needed to assess the robustness of the final outcome and to analyse how much each source of uncertainty contributes to the output variance. The current paper reports on these issues, using the Technology Achievement Index as an illustration. 相似文献
107.
Lothar Rogge 《manuscripta mathematica》1972,7(3):299-306
It is well known that each dominated family of probability measures is compact in the sense of Pitcher. In this paper the converse direction is investigated. It is shown that a family of probability measures on a-field is dominated if it is compact with respect to each sub- -field. If is only compact with respect to the basic-field settheoretical assumptions are needed to obtain domination. 相似文献
108.
R. Sprickmann K. T. Knöpfle D. Ingham M. Rogge C. Mayer-Böricke H. V. Geramb 《Zeitschrift für Physik A Hadrons and Nuclei》1975,274(4):339-342
The differential cross-sections for the elastic scattering of protons from12C with incident energies ranging in approximately 2 MeV steps between 20 and 50 MeV, are analyzed using a standard optical model. 相似文献
109.
A. Budzanowski G. Baur R. Shyam J. Bojowald W. Oelert G. Riepe M. Rogge P. Turek F. Rösel D. Trautmann 《Zeitschrift für Physik A Hadrons and Nuclei》1979,293(4):293-299
The triton-proton angular correlation function has been measured for the58Ni(α, t p)58Ni reaction leading to the ground state of the target nucleus. The obtained experimental data have been interpreted in terms of the direct break-up (fragmentation) of the alpha particle on the target nucleus potential. It is shown that the main features of the measured double differential cross section are well predicted by the DWBA theory of the break-up. The dependence of the elastic and inclusive break-up cross sections upon the fragment-target interaction potentials is discussed. 相似文献
110.
In the future, global energy balance of a Smart Grid system can be achieved by its agents deciding on their own power demand and production (locally) and the exchange of these decisions. In this paper, we develop a network model that describes how the information of power imbalance of individual agents can be exchanged in the system. Compared to existing network models with hierarchical structures, our developed model, together with a market mechanism, achieve the power balance in the system in a completely distributed way. Additionally, dynamics, constraints and forecasts of each agent can be conveniently involved. 相似文献