全文获取类型
收费全文 | 219篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学 | 153篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 13篇 |
物理学 | 51篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2016年 | 7篇 |
2014年 | 2篇 |
2013年 | 8篇 |
2012年 | 11篇 |
2011年 | 20篇 |
2010年 | 7篇 |
2009年 | 4篇 |
2008年 | 16篇 |
2007年 | 8篇 |
2006年 | 11篇 |
2005年 | 13篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 5篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1987年 | 2篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 6篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 3篇 |
1965年 | 2篇 |
1961年 | 1篇 |
1960年 | 3篇 |
1959年 | 3篇 |
1948年 | 2篇 |
1902年 | 1篇 |
排序方式: 共有221条查询结果,搜索用时 31 毫秒
11.
Foldamer simulations: novel computational methods and applications to poly-phenylacetylene oligomers
We apply several methods to probe the ensemble kinetic and structural properties of a model system of poly-phenylacetylene (pPA) oligomer folding trajectories. The kinetic methods employed included a brute force accounting of conformations, a Markovian state matrix method, and a nonlinear least squares fit to a minimalist kinetic model used to extract the folding time. Each method gave similar measures for the folding time of the 12-mer chain, calculated to be on the order of 7 ns for the complete folding of the chain from an extended conformation. Utilizing both a linear and a nonlinear scaling relationship between the viscosity and the folding time to correct for a low simulation viscosity, we obtain an upper and a lower bound for the approximate folding time within the range 70 ns相似文献
12.
Aqueous solution of potassium persulfate converts water-insoluble carboxylic acids in ether (or dichloromethane), to peracids in a yield of 80–90% under the catalytic influence of benzyltriethylammonium chloride (BTEAC) or polyethyleneglycol (PEG-400). The reaction is further catalyzed kinetically in presence of a sulfonated polymer. 相似文献
13.
14.
15.
We propose an efficient method for the prediction of protein folding rate constants and mechanisms. We use molecular dynamics simulation data to build Markovian state models (MSMs), discrete representations of the pathways sampled. Using these MSMs, we can quickly calculate the folding probability (P(fold)) and mean first passage time of all the sampled points. In addition, we provide techniques for evaluating these values under perturbed conditions without expensive recomputations. To demonstrate this method on a challenging system, we apply these techniques to a two-dimensional model energy landscape and the folding of a tryptophan zipper beta hairpin. 相似文献
16.
By using distributed computing techniques and a supercluster of more than 20,000 processors we simulated folding of a 20-residue Trp Cage miniprotein in atomistic detail with implicit GB/SA solvent at a variety of solvent viscosities (gamma). This allowed us to analyze the dependence of folding rates on viscosity. In particular, we focused on the low-viscosity regime (values below the viscosity of water). In accordance with Kramers' theory, we observe approximately linear dependence of the folding rate on 1/gamma for values from 1-10(-1)x that of water viscosity. However, for the regime between 10(-4)-10(-1)x that of water viscosity we observe power-law dependence of the form k approximately gamma(-1/5). These results suggest that estimating folding rates from molecular simulations run at low viscosity under the assumption of linear dependence of rate on inverse viscosity may lead to erroneous results. 相似文献
17.
Defibrillation via the elimination of spiral turbulence in a model for ventricular fibrillation 总被引:6,自引:0,他引:6
Ventricular fibrillation, the major reason behind sudden cardiac death, is turbulent cardiac electrical activity in which rapid, irregular disturbances in the spatiotemporal electrical activation of the heart make it incapable of any concerted pumping action. Methods of controlling ventricular fibrillation include electrical defibrillation as well as injected medication. Electrical defibrillation, though widely used, involves subjecting the whole heart to massive, and often counterproductive, electrical shocks. We propose a defibrillation method that uses a very low-amplitude shock (of order mV) applied for a brief duration (of order 100 ms) and over a coarse mesh of lines on our model ventricle. 相似文献
18.
19.
Photoinduced charge separation in donor–acceptor conjugates plays a pivotal role in technology breakthroughs, especially in the areas of efficient conversion of solar energy into electrical energy and fuels. Extending the lifetime of the charge separated species is a necessity for their practical utilization, and this is often achieved by following the mechanism of natural photosynthesis where the process of electron/hole migration occurs distantly separating the radical ion pairs. Here, we hypothesize and demonstrate a new mechanism to stabilize the charge separated states via the process of electron exchange among the different acceptor entities in multimodular donor–acceptor conjugates. For this, star-shaped, central triphenylamine derived, dimethylamine–tetracyanobutadiene conjugates have been newly designed and characterized. Electron exchange was witnessed upon electroreduction in conjugates having multiple numbers of electron acceptors. Using ultrafast spectroscopy, the occurrence of excited state charge separation, and the effect of electron exchange in prolonging the lifetime of charge separated states in the conjugates having multiple acceptors have been successfully demonstrated. This work constitutes the first example of stabilizing charge-separated states via the process of electron exchange.The significance of electron exchange in stabilizing the charge-separated state is revealed in multi-modular donor–acceptor conjugates. 相似文献
20.
Mark S. Friedrichs Peter Eastman Vishal Vaidyanathan Mike Houston Scott Legrand Adam L. Beberg Daniel L. Ensign Christopher M. Bruns Vijay S. Pande 《Journal of computational chemistry》2009,30(6):864-872
We describe a complete implementation of all‐atom protein molecular dynamics running entirely on a graphics processing unit (GPU), including all standard force field terms, integration, constraints, and implicit solvent. We discuss the design of our algorithms and important optimizations needed to fully take advantage of a GPU. We evaluate its performance, and show that it can be more than 700 times faster than a conventional implementation running on a single CPU core. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009 相似文献