全文获取类型
收费全文 | 210篇 |
免费 | 11篇 |
专业分类
化学 | 109篇 |
力学 | 3篇 |
数学 | 55篇 |
物理学 | 54篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2012年 | 10篇 |
2011年 | 9篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 9篇 |
2007年 | 14篇 |
2006年 | 12篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 8篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1958年 | 2篇 |
1943年 | 3篇 |
1942年 | 1篇 |
1868年 | 1篇 |
1863年 | 3篇 |
排序方式: 共有221条查询结果,搜索用时 546 毫秒
1.
M. Benassi R. D. M. Garcia C. E. Siewert 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1984,35(3):308-320
Several representations of the dispersion matrix (z) basic to analytical solutions for a theory of radiative transfer that includes the effects of polarization are reported, and a method for computing the zeros of det (z) is discussed. Numerical results are given for several specific models.
Zusammenfassung Verschiedene Darstellungen der Dispersionsmatrix (z), welche grundlegende Bedeutung für die analytischen Lösungen der Theorie der Strahlungsübertragung mit Polarisation hat, werden angegeben. Eine Methode zur Berechnung der Nullstellen von det (z) wird diskutiert. Es werden numerische Ergebnisse für verschiedene Modelle angegeben.相似文献
2.
Molecular dynamics simulations have been used to study the spontaneous aggregation of a concentrated solution of dipalmitoylphosphatidylcholine (DPPC) molecules in water into a small vesicle. The molecules were represented in atomistic detail. Starting from a DPPC solution in water, an oblong vesicle with a long axis of 15 nm and short axes of 10 nm was formed spontaneously. After 90 ns of simulation, the vesicle contained a number of water pores. Water pores were shown to facilitate exchange of lipids between inner and outer leaflets. Lipid tails were shown to be less ordered in the inner leaflet of the vesicle, as compared to those in the outer leaflet of the vesicle and an equilibrated lamellar bilayer. 相似文献
3.
Riccardo Baron Daniel Trzesniak Alex H de Vries Andreas Elsener Siewert J Marrink Wilfred F van Gunsteren 《Chemphyschem》2007,8(3):452-461
Thermodynamic data are often used to calibrate or test amomic-level (AL) force fields for molecular dynamics (MD) simulations. In contrast, the majority of coarse-grained (CG) force fields do not rely extensively on thermodynamic quantities. Recently, a CG force field for lipids, hydrocarbons, ions, and water, in which approximately four non-hydrogen atoms are mapped onto one interaction site, has been proposed and applied to study various aspects of lipid systems. To date, no extensive investigation of its capability to describe salvation thermodynamics has been undertaken. In the present study, a detailed picture of vaporization, solvation, and phase-partitioning thermodynamics for liquid hydrocarbons and water was obtained at CG and AL resolutions, in order to compare the two types or models and evaluate their ability to describe thermodynamic properties in the temperature range between 263 and 343 K. Both CG and AL models capture the experimental dependence of the thermodynamic properties on the temperature, albeit a systematically weaker dependence is found for the CG model. Moreover, deviations are found for solvation thermodynamics and for the corresponding enthalpy-entropy compensation for the CG model. Particularly water/oil repulsion seems to be overestimated. However, the results suggest that the thermodynamic properties considered should be reproducible by a CG model provided it is reparametrized on the basis of these liquid-phase properties. 相似文献
4.
5.
Improved Synthesis of Cyclic Tertiary Allylic Alcohols by Asymmetric 1,2‐Addition of AlMe3 to Enones
Dipl.‐Chem. Andreas Kolb Wei Zuo Dr. Jürgen Siewert Dr. Klaus Harms Prof. Dr. Paultheo von Zezschwitz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(48):16366-16373
The development of an improved protocol for the enantioselective RhI/binap‐catalysed 1,2‐addition of AlMe3 to cyclic enones is reported. 31P NMR analysis of the reaction revealed that the catalyst in its resting state is a chloride‐bridged dimer. This insight led to the use of AgBF4 as an additive for in situ activation of the dimeric precatalyst. Thus, the catalyst loading can now be reduced to only 1 mol % with respect to rhodium. Various 5–7‐membered cyclic enones can be transformed into tertiary allylic alcohols with excellent levels of enantioselectivity and high yields. The obtained products are versatile synthetic building blocks, shown by a highly enantioselective formal total synthesis of the pheromone (?)‐frontalin as well as formation of a bicyclic lactone that has the core structure of the natural flavour component “wine lactone”. 相似文献
6.
C. E. Siewert 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1979,30(3):522-525
The inverse problem for a linearly anisotropically scattering model in the theory of radiative transfer or neutron transport is solved, in terms only of surface quantities, for a finite slab.
Zusammenfassung Das inverse Problem für ein linear anisotropes Streumodell in der Theorie der Strahlungsübertragung oder der Neutronen-Transporttheorie wird gelöst; für eine endliche Schicht wird die Lösung mit Hilfe von Oberflächengrössen ausgedrückt.相似文献
7.
8.
Using a coarse-grained molecular model we study the spatial distribution of lipid domains on a 20-nm-sized vesicle. The lipid mixture laterally phase separates into a raftlike, liquid-ordered (l(o)) phase and a liquid-disordered phase. As we uniaxially compress the mixed vesicle keeping the enclosed volume constant, we impart tension onto the membrane. The vesicle adopts a barrel shape, which is composed of two flat contact zones and a curved edge. The l(o) domain, which exhibits a higher bending rigidity, segregates to the highly curved edge. This inverted domain sorting switches to normal domain sorting, where the l(o) domain prefers the flat contact zone, when we release the contents of the vesicle. We rationalize this domain sorting by a pronounced reduction of the bending rigidity and area compressibility of the l(o) phase upon bending. 相似文献
9.
10.