全文获取类型
收费全文 | 358篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 123篇 |
晶体学 | 3篇 |
力学 | 58篇 |
数学 | 90篇 |
物理学 | 88篇 |
出版年
2021年 | 3篇 |
2020年 | 5篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 17篇 |
2014年 | 4篇 |
2013年 | 23篇 |
2012年 | 14篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 9篇 |
2008年 | 20篇 |
2007年 | 9篇 |
2006年 | 14篇 |
2005年 | 14篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1996年 | 6篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1980年 | 3篇 |
1977年 | 3篇 |
1975年 | 7篇 |
1974年 | 10篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1969年 | 4篇 |
1964年 | 3篇 |
1963年 | 2篇 |
1925年 | 2篇 |
1924年 | 2篇 |
1905年 | 3篇 |
1880年 | 2篇 |
排序方式: 共有362条查询结果,搜索用时 15 毫秒
91.
92.
Eliot AC Griffin BM Thomas PM Johannes TW Kelleher NL Zhao H Metcalf WW 《Chemistry & biology》2008,15(8):765-770
The antibiotics fosmidomycin and FR900098 are members of a unique class of phosphonic acid natural products that inhibit the nonmevalonate pathway for isoprenoid biosynthesis. Both are potent antibacterial and antimalarial compounds, but despite their efficacy, little is known regarding their biosynthesis. Here we report the identification of the Streptomyces rubellomurinus genes required for the biosynthesis of FR900098. Expression of these genes in Streptomyces lividans results in production of FR900098, demonstrating their role in synthesis of the antibiotic. Analysis of the putative gene products suggests that FR900098 is synthesized by metabolic reactions analogous to portions of the tricarboxylic acid cycle. These data greatly expand our knowledge of phosphonate biosynthesis and enable efforts to overproduce this highly useful therapeutic agent. 相似文献
93.
94.
95.
96.
Eliot P. Botosoa Virginie Silvestre Richard J. Robins Jose Manuel Moreno Rojas Claude Guillou Gérald S. Remaud 《Journal of chromatography. A》2009,1216(42):7043-7048
Quantitative isotopic 13C NMR at natural abundance has been used to determine the site-by-site 13C/12C ratios in vanillin and a number of related compounds eluted from silica gel chromatography columns under similar conditions. Head-to-tail isotope fractionation is observed in all compounds at the majority of carbon positions. Furthermore, the site-specific isotope deviations show signatures characteristic of the position and functionality of the substituents present. The observed effects are more complex than would be obtained by simply summing the individual effects. Such detail is hidden when only the global 13C content is measured by mass spectrometry. In particular, carbon positions within the aromatic ring are found to show site-specific isotope fractionation between the solute and the stationary phase. These interactions, defined as non-covalent isotope effects, can be normal or inverse and vary with the substitution pattern present. 相似文献
97.
We report an improved implementation of the Wood–Kirkwood kinetic detonation model based on a multi-species Buckingham exponential-6
equation of state (EOS) and multiple reaction rate laws. The exp-6 EOS allows for treatment of chemical systems at a statistical
mechanics level, instead of an atomistic level. Finite global rate laws are used for the slowest chemical reactions. Other
reactions are given infinite rates and are kept in constant thermodynamic equilibrium. The global rates do not necessarily
correspond to a specific physical process, but rather to the sum total of slow physical processes. We model ideal and non-ideal
composite energetic materials. We find that using the exp-6 non-ideal model improves the accuracy. The detonation velocity
as a function of charge radius is also correctly reproduced.
Contribution to the Mark S. Gordon on 65th Birthday Festschrift Issue. 相似文献
98.
99.
The calculation of thermochemical data requires accurate molecular energies and heat capacities. Traditional methods rely upon the standard harmonic normal-mode analysis to calculate the vibrational and rotational contributions. We utilize path-integral Monte Carlo for going beyond the harmonic analysis and to calculate the vibrational and rotational contributions to ab initio energies. This is an application and an extension of a method previously developed in our group [J. Chem. Phys. 118, 1596 (2003)]. 相似文献
100.