全文获取类型
收费全文 | 150篇 |
免费 | 1篇 |
专业分类
化学 | 39篇 |
力学 | 3篇 |
数学 | 9篇 |
物理学 | 100篇 |
出版年
2023年 | 1篇 |
2019年 | 1篇 |
2016年 | 3篇 |
2014年 | 4篇 |
2013年 | 2篇 |
2012年 | 7篇 |
2011年 | 11篇 |
2010年 | 8篇 |
2009年 | 4篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 5篇 |
1998年 | 1篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1973年 | 3篇 |
1930年 | 1篇 |
排序方式: 共有151条查询结果,搜索用时 0 毫秒
1.
2.
Wijkens P Jastrzebski JT van Der Schaaf PA Kolly R Hafner A van Koten G 《Organic letters》2000,2(11):1621-1624
A general method for the functionalization of Si-Cl terminated carbosilane dendritic molecules via organolithium or organomagnesium reagents is described. Quantitative exchange of the bromine atoms of 4-bromophenyl-functionalized dendrimers affords polylithiated species that are valuable starting materials for further functionalization, e.g., into pyridyl alcohols. The latter were successfully applied as catalyst precursors in a ruthenium-mediated ring-closure metathesis reaction. 相似文献
3.
4.
Spiroplasma bacteria propel through viscous fluids by sending kinks or domain walls between regions of opposite handedness down their helical body. A simple elastic model for the domain-wall propagation is formulated and studied using hydrodynamic simulations and scaling arguments, giving good agreement with recent video-microscopy observations. It is shown that the observed helical bacterial pitch angle psi approximately 35 degrees is optimized for maximal speed and efficiency. 相似文献
5.
A single flexible polymer in strong sedimentation fields is investigated using hydrodynamic simulations and scaling arguments. For short chains and small fields compaction is observed. For elevated fields or long chains the chain stretches and the sedimentation coefficient decreases, in agreement with ultracentrifuge experiments on linear as well as circular DNA. For very large fields a tadpole forms consisting of a compact leading head and a trailing stretched tail. 相似文献
6.
The study of network formation during the curing of an epoxy-resin with anhydride and tertiary amine has been carried out by the Monte Carlo method. Both dynamical and structural properties are studied. The model resembles the well known cluster-cluster aggregation: the reaction is modelled as a “geometrical” phenomenon and neglects attractive and repulsive energies except for an excluded volume condition. A reaction occurs always when two active sites are in the vicinity to each other, meaning that the “chemical” processes are taken to be much faster than diffusion (as in diffusion-limited aggregation). Results are presented of two-dimensional square lattice simulations with periodic boundary conditions and are discussed with respect to the proposed mechanism of the curing reaction and to the assumptions of the diffusion-limited nature of the processes. The scope and limitations of such two-dimensional simulations are discussed. 相似文献
7.
A review of atomistic simulation approaches including explicit water for the study of hydration forces between polar surfaces is presented. In particular, we discuss different methods for keeping the chemical potential of water constant and compare advantages and limitations of each method. It turns out that modifications of hydration forces due to surface softness can be accounted for by a convolution over the surface shape profile. Universal aspects of the hydration interaction observed in simulations of different surface chemistries are highlighted, while special attention is given to hydration forces between self-assembled phospholipid membranes. 相似文献
8.
Experimental single-molecule stretching curves for three backbone architectures (single-stranded DNA, various types of peptides, polyvinylamine) are quantitatively compared with corresponding quantum-chemical (zero-temperature) ab-initio calculations in the high-force range of up to two nanonewtons. For high forces, quantitative agreement is obtained with the contour length of the polymers as the only fitting parameter. For smaller forces, the effects of chain fluctuations are accounted for by using recent theoretical results for the stretching response of a freely-rotating-chain model. 相似文献
9.
We reconsider the electrostatic contribution to the persistence length,
, of a single, infinitely long-charged polymer in the presence of screening. A Gaussian variational method is employed, taking
as the only variational parameter. For weakly charged and flexible chains, crumpling occurs at small length scales because conformational fluctuations overcome electrostatic repulsion. The electrostatic persistence length depends on the square of the screening length,
, as first argued by Khokhlov and Khachaturian by applying the Odijk-Skolnick-Fixman (OSF) theory to a string of crumpled blobs. We compare our approach to previous theoretical works (including variational formulations) and show that the result
found by several authors comes from the improper use of a cutoff at small length scales. For highly charged and stiff chains, crumpling does not occur; here we recover the OSF result and validate the perturbative calculation for slightly bent rods.PACS:
36.20.-r Macromolecules and polymer molecules - 82.70.-y Disperse systems; complex fluids - 87.15.-v Biomolecules: structure and physical properties 相似文献
10.
G. Stobrawa M. Hacker R. Netz M. Bischoff R. Sauerbrey 《Applied physics. B, Lasers and optics》2003,76(3):333-336
We present a novel method for measuring the linear and nonlinear dispersion properties of conventional and micro-structured
fibers. It is based on the automated compensation of phase modulations using a high-resolution pulse-shaping device. No tunable
laser source is required.
Received: 20 December 2002 / Published online: 19 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-3641/947202, E-mail: stobrawa@ioq.uni-jena.de
RID="**"
ID="**"Present address: Carl Zeiss Meditec AG, G?schwitzer Strasse 51–52, 07745 Jena, Germany 相似文献