全文获取类型
收费全文 | 248篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 183篇 |
晶体学 | 5篇 |
力学 | 3篇 |
数学 | 15篇 |
物理学 | 47篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2017年 | 1篇 |
2015年 | 5篇 |
2014年 | 1篇 |
2013年 | 20篇 |
2012年 | 10篇 |
2011年 | 9篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 15篇 |
2007年 | 18篇 |
2006年 | 13篇 |
2005年 | 13篇 |
2004年 | 14篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 10篇 |
1996年 | 2篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1974年 | 4篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有253条查询结果,搜索用时 15 毫秒
1.
2.
Kohji Masaki Shin-ichi Ohkawara Tomohiro Hirano Makiko Seno Tsuneyuki Sato 《Journal of polymer science. Part A, Polymer chemistry》2004,42(17):4437-4447
The crosslinking reaction of 1,2-polybutadiene (1,2-PB) with dicumyl peroxide (DCPO) in dioxane was kinetically studied by means of Fourier transform near-infrared spectroscopy (FTNIR). The crosslinking reaction was followed in situ by the monitoring of the disappearance of the pendant vinyl group of 1,2-PB with FTNIR. The initial disappearance rate (R0) of the vinyl group was expressed by R0 = k[DCPO]0.8[vinyl group]−0.2 (120 °C). The overall activation energy of the reaction was estimated to be 38.3 kcal/mol. The unusual rate equation was explained in terms of the polymerization of the pendant vinyl group as an allyl monomer involving degradative chain transfer to the monomer. The reaction mixture involved electron spin resonance (ESR)-observable polymer radicals, of which the concentration rapidly increased with time owing to a progress of crosslinking after an induction period of 200 min. The crosslinking reaction of 1,2-PB with DCPO was also examined in the presence of vinyl acetate (VAc), which was regarded as a copolymerization of the vinyl group with VAc. The vinyl group of 1,2-PB was found to show a reactivity much higher than 1-octene and 3-methyl-1-hexene as model compounds in the copolymerization with VAc. This unexpectedly high reactivity of the vinyl group suggested that an intramolecular polymerization process proceeds between the pendant vinyl groups located on the same polymer chain, possibly leading to the formation of block-like polymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4437–4447, 2004 相似文献
3.
Let P(z) be a polynomial of degree n with complex coefficients and consider the n–th order linear differential operator P(D). We show that the equation P(D)f = 0 has the Hyers–Ulam stability, if and only if the equation P(z) = 0 has no pure imaginary solution. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
4.
5.
6.
K. Nakanishi T. Masukawa T. Nadai K. Yoshii S. Okada K. Miyajima 《Journal of inclusion phenomena and macrocyclic chemistry》1996,25(1-3):181-184
Triacetyl--cyclodextrin (TA--CyD), a hydrophobic cyclodextrin derivative, that is insoluble in water, was used to form a complex with flufenamic acid (FA). FA-TA--CyD complex formation was demonstrated by differential scanning calorimetry and powder X-ray diffractometry. The release rate of FA from the FA-TA--CyD complexes in phosphate buffer pH 6.8 was significantly retarded compared to that of FA from the FA and glucose mixture. When the FA-TA--CyD complexes were administered directly into the intraduodenal lumen, the plasma concentration of FA remained at a plateau level (10-18 g/ml) for 6–8 h. An increased mean residence time of FA following FA-TA--CyD complexes administration was observed. These results indicate that TA--CyD may serve as a hydrophobic carrier in prolonged-release preparations of FA. 相似文献
7.
Mass spectrometric determination of glycosylation sites and oligosaccharide composition of insect-expressed mouse interleukin-3 总被引:2,自引:0,他引:2
M Svoboda M Przybylski J Schreurs A Miyajima K Hogeland M Deinzer 《Journal of chromatography. A》1991,562(1-2):403-419
The primary structure of Baculovirus-expressed mouse interleukin-3 produced in infected Bombyx mori larvae was characterized by liquid secondary ion mass spectrometry and 252Cf-plasma desorption mass spectrometry in combination with selected protein microchemical reactions. Interleukin-3 was found to consist of at least two glycoprotein species of ca. 17,000 dalton. Characterization of tryptic and S. aureus V8 protease peptides by Edman degradation combined with plasma desorption mass spectrometry showed that two N-glycosylation sites. Asn-16 and Asn-86, were present. N-Glycan residues were shown by liquid secondary ion mass spectrometry and high-performance liquid chromatography to consist of mannose, fucose, and glucosamine. The presence of galactosamine indicated that O-glycosylated residues were present, in addition to the N-glycosylated residues. Glucose was also present, which indicated incomplete processing of the insect-expressed N-linked oligosaccharides. 相似文献
8.
Kawahara K Sekiguchi A Kiyoki E Ueda T Shimamura K Kurosaki Y Miyaoka S Okabe H Miyajima M Kimura J 《Chemical & pharmaceutical bulletin》2003,51(3):336-338
Newly formulated cationic liposomes (TRX-liposomes) with four different mean diameters were injected into twelve male rats via the lateral tail vein in order to evaluate the effect of liposomal size on pharmacokinetic parameters. TRX-liposomes disappeared from the blood according to the one-compartment model and demonstrated maximum and minimum half-lives of ca. 14 h (mean diameter of 114.3 nm) and ca. 5 h (mean diameter of 285.9 nm), respectively. This prolonged half-life tended to decrease at the boundary of 114.3 nm mean diameter. The optimal size (114.3 nm) for prolonged circulation of TRX-liposomes was consistent with that of pegylated liposomes such as Doxil((R)), however, the half-life was different among these liposomes. The electric charge of the TRX-liposomal surface is assumed to be responsible for this difference. The results of the present study will be very useful in the design of long-circulating cationic liposomes. 相似文献
9.
I. Yamamoto M. Nishii E. Tokuoka T. Handa K. Miyajima 《Colloid and polymer science》1997,275(7):627-633
We evaluated the hydrolysis of egg yolk phosphatidylcholine (PC) by phospholipase D from Streptomyces chromofuscus (PLD) in small unilamellar vesicles (SUV) in presence of 50 μM Ca2+. After initial choline production (hydrolysis of 1.5% of the PC at the outer leaflets of the vesicle bilayers), the hydrolysis
was reduced to 5% of the initial velocity. The kinetic behavior in SUV of premixed PC and a low percentage of the hydrolysis
product, phosphatidic acid (PA), was similar to that of PC SUV. The reduced velocity disappeared when the membrane structure
was disintegrated by means of a nonionic surfactant. In the retardation phase, the partially hydrolyzed vesicles (postsubstrates)
had much higher affinity for PLD than fresh PC SUV. These results indicated that small clusters of the product, PA, at the
vesicle surface were responsible for the reduced velocity of hydrolysis.
The initial velocity increased in a biphasic manner with the substrate concentration. At a PC concentration range up to 4 mM,
the experimental data fit Michaelis–Menten kinetics. At concentrations above 6 mM, the velocity again markedly increased.
Negatively charged mixed vesicles of PC and PA did not have such kinetics. Furthermore, adding PC SUV to the postsubstrates,
where the fraction of free PLD was less than 0.05, induced steep choline production. These results showed that PLD bound to
vesicles had higher activity than free PLD. We speculated that PLD bound to vesicles collided with and was directly transferred
to PC SUV when the fraction of free PLD in aqueous medium was very small.
Received: 5 November 1996 Accepted: 26 February 1997 相似文献
10.
The most effective optical isomer (1-) of permethric acid (, R = H), a potent intermediate in the production of synthetic pyrethroid, was enantioselectively prepared. 相似文献