全文获取类型
收费全文 | 226篇 |
免费 | 2篇 |
专业分类
化学 | 183篇 |
数学 | 5篇 |
物理学 | 40篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 11篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 14篇 |
2007年 | 22篇 |
2006年 | 22篇 |
2005年 | 15篇 |
2004年 | 16篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1972年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有228条查询结果,搜索用时 15 毫秒
1.
Eitan Altman Konstantin Avrachenkov Richard Marquez Gregory Miller 《Mathematical Methods of Operations Research》2005,62(3):375-386
We consider a zero-sum stochastic game with side constraints for both players with a special structure. There are two independent
controlled Markov chains, one for each player. The transition probabilities of the chain associated with a player as well
as the related side constraints depend only on the actions of the corresponding player; the side constraints also depend on
the player’s controlled chain. The global cost that player 1 wishes to minimize and that player 2 wishes to maximize, depend
however on the actions and Markov chains of both players. We obtain a linear programming formulations that allows to compute
the value and saddle point policies for this problem. We illustrate the theoretical results through a zero-sum stochastic
game in wireless networks in which each player has power constraints 相似文献
2.
[reaction: see text] The fluorescence quenching of 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) by nucleotides has been studied. The quenching mechanism was analyzed on the basis of deuterium isotope effects, tendencies for exciplex formation, and the quenching efficiency in the presence of a molecular container (cucurbit[7]uril). Exciplex-induced quenching appears to prevail for adenosine, cytidine, and uridine, while hydrogen abstraction becomes competitive for thymidine and guanosine. Compared to other fluorescent probes, DBO responds very selectively to the type of nucleotide. 相似文献
3.
4.
5.
6.
7.
8.
9.
We describe the purification of a single-strand nuclease from Aspergillus oryzae using the first commercial prototype of an instrument (RF3TM) designed by Milan Bier et al. for preparative-scale isoelectric focusing. Protein separation takes place entirely in solution, with shear-stabilized laminar flow counteracting convective disturbances generated by the electric field. Conditions for isoelectric focusing were determined by focusing fractions with nuclease activity, following chromatography on DEAE-Sepharose, in analytical gels containing carrier ampholytes. The separation was then scaled up to process larger quantities of protein in the RF3. When partially-purified protein (250 mg, 6700 U/mg) was focused in pH 3-4 carrier ampholytes. 67% of the activity was recovered in pooled peak fractions with a specific activity of 54,000 U/mg protein. Overall, 82% of the activity loaded on the RF3 was recovered. Eliminating two steps prior to isoelectric focusing, and increasing the protein load from 250 mg to 1.2 g, produced an enzyme with a nearly four-fold increase in specific activity (from 4000 U/mg protein to 15,000 U/mg protein) but with unacceptable color. Our results indicate that a high quality enzyme can be prepared in quantity when heat denaturation and ammonium sulfate precipitation are included prior to isoelectric focusing. 相似文献
10.
The reaction of Δ2 -oxazolin-5-ones 1a and 1b with nickel peroxide in benzene produces the corresponding 4,4-dehydrodimers 5a and 5b as the main products in yields over 75%. Under the same conditions, the 2-aryl -4-methyl - Δ2-oxazolin-5-ones 1c, 1d and 1e yield five products. In the case of 1c, the constituents of the product mixture were separated and identified as two 4,4-dehydrodimers ( meso and d] pair isomers) 5c and 5c', (40.7%), 2,4-dehydrodimer 6c (34.9%), acetylanisoylimide 8c (8.5%) and anisamide (15.9%). Adequate mechanistic schemes are discussed to account for the products formed. 相似文献