全文获取类型
收费全文 | 327篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
化学 | 224篇 |
晶体学 | 1篇 |
力学 | 7篇 |
数学 | 40篇 |
物理学 | 67篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 9篇 |
2013年 | 10篇 |
2012年 | 12篇 |
2011年 | 16篇 |
2010年 | 6篇 |
2009年 | 11篇 |
2008年 | 19篇 |
2007年 | 17篇 |
2006年 | 13篇 |
2005年 | 12篇 |
2004年 | 16篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 9篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1968年 | 2篇 |
1907年 | 5篇 |
1902年 | 1篇 |
1894年 | 2篇 |
排序方式: 共有339条查询结果,搜索用时 281 毫秒
41.
Moody JD Williams EA Glenzer SH Young PE Hawreliak J Gouveia A Wark JS 《Physical review letters》2003,90(24):245001
We investigate the distortion of a spatial intensity modulation imposed on a 527 nm f/10 probe beam as it transmits through an underdense plasma characterized with Thomson scattering. Combining the measurements with full wave simulations of beam propagation through the entire plasma show that the key features of the data can be reproduced using the Kaiser thermal transport model. 相似文献
42.
43.
Abstract. There is a growing body of results in the theory of discrete point sets and tiling systems giving conditions under which
such systems are pure point diffractive. Here we look at the opposite direction: what can we infer about a discrete point
set or tiling, defined through a primitive substitution system, given that it is pure point diffractive? Our basic objects
are Delone multisets and tilings, which are self-replicating under a primitive substitution system of affine mappings with
a common expansive map Q . Our first result gives a partial answer to a question of Lagarias and Wang: we characterize repetitive substitution Delone
multisets that can be represented by substitution tilings using a concept of ``legal cluster.' This allows us to move freely
between both types of objects. Our main result is that for lattice substitution multiset systems (in arbitrary dimensions),
being a regular model set is not only sufficient for having pure point spectrum—a known fact—but is also necessary.
This completes a circle of equivalences relating pure point dynamical and diffraction spectra, modular coincidence, and model
sets for lattice substitution systems begun by the first two authors of this paper. 相似文献
44.
The total synthesis of the unusual 4-pyridone marine metabolite lodopyridone has been achieved by late stage manipulation of the related 4-pyrone. Key reactions include a Suzuki–Miyaura coupling to form the tetracyclic core and a modified Corey–Ganem–Gilman reaction to install the ethanolamide side-chain. 相似文献
45.
A tri-enzyme electrode has been developed for determining starch in a flowing stream based on amperometric monitoring of hydrogen peroxide at a potential of +600 mV versus a silver--silver chloride reference electrode. The nylon-based starch-sensing membranes (over a platinum electrode) were prepared from an enzyme cocktail containing various ratios of amyloglucosidase (AMG), mutarotase (MUT) and glucose oxidase (GO). The best starch-sensing membrane (to give the type A electrode) was made from an enzyme cocktail of AMG--MUT--GO (2000 + 100 + 100 U; where 1 U = 16.67 nanokatals), i.e., containing a high level of AMG. In this system, starch samples were first incubated with soluble alpha-amylase (alpha-AMY) (1000 U) for 1 h at room temperature prior to analysis with the tri-enzyme electrode. Attempts were also made to immobilize alpha-AMY on to nylon net, either alone or as a component of a four-membrane starch-enzyme electrode but starch signals were weak compared with those generated by starch pre-treated with soluble alpha-AMY. This system, associated with the type A starch electrode, not only exhibited a calibration of wide linear range (1 x 10(-4)-0.1% m/v starch) but also showed promising operational properties. It has excellent thermal stability over the range 30-70 degrees C. 相似文献
46.
R. V. Moody L. Motlochová J. Patera 《Journal of Fourier Analysis and Applications》2014,20(6):1257-1290
Lie groups with two different root lengths allow two ‘mixed sign’ homomorphisms on their corresponding Weyl groups, which in turn give rise to two families of hybrid Weyl group orbit functions and characters. In this paper we extend the ideas leading to the Gaussian cubature formulas for families of polynomials arising from the characters of irreducible representations of any simple Lie group, to new cubature formulas based on the corresponding hybrid characters. These formulas are new forms of Gaussian cubature in the short root length case and new forms of Radau cubature in the long root case. The nodes for the cubature arise quite naturally from the (computationally efficient) elements of finite order of the Lie group. 相似文献
47.
Gautam Mitra Cormac Lucas Shirley Moody Bjarni Kristjansson 《Computational Optimization and Applications》1995,4(3):263-283
LP models are usually constructed using index sets and data tables which are closely related to the attributes and relations of relational database (RDB) systems. We extend the syntax of MPL, an existing LP modelling language, in order to connect it to a given RDB system. This approach reuses existing modelling and database software, provides a rich modelling environment and achieves model and data independence. This integrated software enables Mathematical Programming to be widely used as a decision support tool by unlocking the data residing in corporate databases. 相似文献
48.
Synthesis and Intracellular Redox Cycling of Natural Quinones and Their Analogues and Identification of Indoleamine‐2,3‐dioxygenase (IDO) as Potential Target for Anticancer Activity
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Christopher E. Blunt Dr. Canan Torcuk Dr. Yang Liu Dr. William Lewis Dr. David Siegel Prof. Dr. David Ross Prof. Dr. Christopher J. Moody 《Angewandte Chemie (International ed. in English)》2015,54(30):8740-8745
Natural quinones, often linked with cellular oxidation processes, exhibit pronounced biological activity. In particular, the structurally unique isothiazolonaphthoquinone aulosirazole, isolated from blue‐green alga, possesses selective antitumor cytotoxicity, although its mechanism of action is unknown. The first synthesis of aulosirazole uses a route centered upon a late‐stage regioselective Diels–Alder reaction. The structurally related natural product pronqodine A, an inhibitor of prostaglandin release, and analogues thereof, were also prepared for comparison. Biological evaluation of the compounds identified one potential target as the immunoregulatory enzyme indoleamine‐2,3‐dioxygenase (IDO). The isothiazoloquinones are also efficient substrates for the human quinone reductase NQO1, and undergo intracellular NQO1‐dependent redox cycling resulting in the generation of reactive oxygen species, and at lower doses have the potential to alter the ratio of intracellular oxidized to reduced pyridine nucleotides. 相似文献
49.
Experimental Techniques - 相似文献
50.
Lucas CL Lygo B Blake AJ Lewis W Moody CJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(6):1972-1978
A study of the regioselectivity of the Claisen rearrangement of meta-allyloxy aryl ketones showed that the electron-withdrawing carbonyl group has a major influence and strongly directs rearrangement to the more hindered ortho position. However, when the ketone is part of a ring structure, its electronic effect can be negated by conversion into its triisopropylsilyl enol ether, which dramatically reverses the regiochemistry of the Claisen rearrangement. DFT calculations suggest that the effect is electronic although there is also a steric effect of the bulky silyl group. This strategy for influencing the regiochemical outcome of the Claisen rearrangement was then employed in a short synthesis of the furo[2,3-g]chromene, (-)-pestalotheol D, that confirms the absolute stereochemistry of the natural product. 相似文献