全文获取类型
收费全文 | 158篇 |
免费 | 4篇 |
专业分类
化学 | 65篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 27篇 |
物理学 | 66篇 |
出版年
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 8篇 |
2012年 | 11篇 |
2011年 | 14篇 |
2010年 | 10篇 |
2009年 | 13篇 |
2008年 | 9篇 |
2007年 | 21篇 |
2006年 | 14篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1976年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有162条查询结果,搜索用时 500 毫秒
71.
Kimmo Eriksson 《Journal of Algebraic Combinatorics》1995,4(3):233-252
We explore the connection between polygon posets, which is a class of ranked posets with an edge-labeling which satisfies certain polygon properties, and the weak order of Coxeter groups. We show that every polygon poset is isomorphic to a join ideal in the weak order, and for Coxeter groups where no pair of generators have infinite order the converse is also true.The class of polygon posets is seen to include the class of generalized quotients defined by Björner and Wachs, while itself being included in the class of alternative generalized quotients also considered by these authors. By studying polygon posets we are then able to answer an open question about common properties of these two classes. 相似文献
72.
Kimmo Peltonen Antti Zitting Heimo Koskinen Ahti Itkonen 《Photochemistry and photobiology》1986,43(5):481-484
Abstract— Irradiation of 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol-A) with UV light causes photo-decomposition of the compound. Spin-trapping with α-phenyl-N-tert-butyl-nitrone showed that free radicals were cleaved from the molecule. No direct ESR-spectroscopic information concerning the structure of the remaining radical skeleton could be obtained. Gas chromatographic mass spectrometric analysis of the decomposition products indicated the existence of a semiquinone structure following cleavage of a methyl radical from 2,2-bis-4–(hydroxyphenyl)-propane. The capacity of 2,2-bis-(4- hydroxyphenyl)-propane to give rise to radicals might explain its photoallergenic properties. 相似文献
73.
Kunnari TJ Ylihonko KP Klika KD Mäntsälä PI Hakala JM 《The Journal of organic chemistry》2000,65(10):2851-2855
The genetic engineering of antibiotic-producing Streptomyces strains is an approach that is emerging and ready to become established as a successful methodology in developing analogues of the original, pharmaceutically important, natural products obtained from the organisms. The current report highlights this succes by demonstrating the high-level production of novel anthracyclines. The biosynthetic pathways of the nogalamycin-producing Streptomyces nogalater and the aclacinomycin-producing S. galilaeus were combined by transferring the genes of S. nogalater polyketide synthetase into a nonproducing S. galilaeus mutant. The resulting anthracycline antibiotics that were produced possessed structural features characteristic of compounds from both of the undoctored Streptomycesstrains. 相似文献
74.
[reaction: see text] Novel nucleosidic phosphoramidite blocks were synthesized by a Mitsunobu reaction between 2'-deoxy-5'-O-(4,4'-dimethoxytrityl)uridine and a primary alcohol containing a conjugate group in its structure (a protected functional group, an organic dye, or a precursor of a lanthanide(III) chelate) followed by phosphitylation. They were used in machine-assisted DNA synthesis in the standard manner. A slightly modified deprotection procedure was used for the preparation of oligonucleotide conjugates tethered to lanthanide(III) chelates. For the latter application one non-nucleosidic block was also synthesized. 相似文献
75.
Practical detection limits were 2 and 10 μg l?1 vanadium for pyrolyte graphite-furnace a.a.s. and d.c.p.-a.e.s., respectively, which allowed screening for urinary vanadium (? 10 μg ?in ? subjects, by direct measurements. Extraction of vanadium with ammonium 1?inecarbodithioate into 4-methylpentan-2-one gave detection limits of 0.5 and ? μg l?1 vanadium, respectively, for the two techniques. 相似文献
76.
Muhammad Zubair Hilde Nybom Christina Lindholm Johanna M. Brandner Kimmo Rumpunen 《Natural product research》2016,30(5):622-624
The wound-healing properties of Plantago major L. (plantain) were evaluated using an ex-vivo porcine wound-healing model. Ethanol- and water-based extracts were prepared from greenhouse-grown and freeze-dried leaves of P. major. Both types of extracts stimulated wound healing in porcine skin, but the ethanol-based extracts had a somewhat stronger effect. A concentration of 1.0 mg/mL (on dry weight basis) produced the best results for both types of extracts. 相似文献
77.
78.
We present well-known interpretations of Lagrange multipliers in physical and economic applications, and introduce a new interpretation in nonlinear pricing problem. The multipliers can be interpreted as a network of directed flows between the buyer types. The structure of the digraph and the fact that the multipliers usually have distinctive values can be used in solving the optimization problem more efficiently. We also find that the multipliers satisfy a conservation law for each node in the digraph, and the non-uniqueness of the multipliers are connected to the stability of the solution structure. 相似文献
79.
Berg S Melamies M Rajamäki M Vainio O Peltonen K 《Analytical and bioanalytical chemistry》2012,402(3):1209-1215
A sensitive and selective method to quantify budesonide in dog plasma samples was developed and fully validated. Liquid–liquid
extraction was followed by solid-phase extraction and liquid chromatography–tandem mass spectrometry with electrospray ionization.
After reconstitution of the analytes in the mobile phase, samples were analysed by reversed-phase liquid chromatography with
isocratic elution. d8-Budesonide was used as an internal standard, and characteristic transitions of d8-budesonide and budesonide
were used for quantification. The method was validated with respect to selectivity, specificity, linearity, recovery, repeatability,
reproducibility and limits of detection and quantification. The validated method was successfully applied to monitor the plasma
levels of budesonide in dogs exposed to clinical doses of inhaled and intravenous drug. 相似文献
80.
A. Kankainen Yu. N. Novikov M. Oinonen L. Batist V. -V. Elomaa T. Eronen J. Hakala A. Jokinen P. Karvonen M. Reponen J. Rissanen A. Saastamoinen G. Vorobjev C. Weber J. ?yst? 《The European Physical Journal A - Hadrons and Nuclei》2012,48(4):1-11
Low-energy-particle-induced fission is a cost-effective way to produce neutron-rich nuclei for spectroscopic studies. Fission has been utilized at the IGISOL to produce isotopes for decay and nuclear structure studies, collinear laser spectroscopy and precision mass measurements. The ion guide technique is also very suitable for the fission yield measurements, which can be performed very efficiently by using the Penning trap for fission fragment identification and counting. The proton- and neutron-induced fission yield measurements at the IGISOL are reviewed, and the independent isotopic yields of Zn, Ga, Rb, Sr, Cd and In in 25MeV deuterium-induced fission are presented for the first time. Moving to a new location next to the high intensity MCC30/15 light-ion cyclotron will allow also the use of the neutron-induced fission to produce the neutron rich nuclei at the IGISOL in the future. 相似文献