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61.
62.
The effect of oxygen on wheat flour lipids during dough mixing was investigated by analysis of the lipid composition and by an ESR technique with a fatty acid spin-label (4,4’-dimethyl-oxazolidine-N-oxyl derivative of 5-ketostearic acid). Dough was prepared in the presence of the spin-label under an atmosphere of air, nitrogen, 95% nitrogen—5% oxygen or oxygen, and the gluten was obtained by washing out the starch. ESR spectra of the spin-label incorporated into the gluten showed decreases in the order parameter, rotational correlation time and activation energy for rotational viscosity with increasing atmospheric oxygen concentration. During dough mixing in oxygen, oxidation of lipids proceeded and bound lipids slightly decreased. These data indicate that modification of lipids by incorporated oxygen leads to an increase in their fluidity and to a decrease in their hydrophobic interaction with protein in dough. 相似文献
63.
The Gram-negative bacterium Acinetobacter species ODB-L2 produces lipopolysaccharide (LPS) in culture broth. The LPS could not be purified by conventional extraction methods using 90% phenol/water or 90% phenol/chloroform/petroleum ether mixed solvent. Extraction was achieved employing an admixture of chloroform, ethanol, and 4 M HCI solution. The LPS was purified from dissolving the crude extracts in 90% phenol and LPS sediment formed by addition of methanol. The LPS was characterized by chemical, biochemical, and physicochemical methods as rough form 3-hydroxydodecanoic acid rich LPS. 相似文献
64.
Toshimasa Toyo’oka 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2009,877(28):3318-3330
Biological aminothiols, such as cysteine, homocysteine, and glutathione, widely occur in animal tissues and fluids. The altered levels of the thiols (reduced forms) and their disulfides (oxidized forms) in physiological liquids have been linked to specific pathological conditions and closely associated with several human diseases. Therefore, it is well recognized that the determination of thiols and disufides is important in order to understand their physiological roles. The derivatization utilizing a suitable labeling reagent followed by chromatographic separation and detection is the most reliable means for sensitive and selective assays. Many reagents have typically been synthesized and successfully used for the determination of thiols and disulfides in biological specimens. The development of new reagents for highly sensitive detection is still continuing. This review describes the approaches for the separation assay of various thiol compounds, obtained through the analytical papers published in 2000–2008. The derivatization reagents are categorized with each type of chromophore and fluorophore and evaluated in terms of their reactivity, stability, detection wavelength, handling, sensitivity and selectivity. Application examples of the reagents for bioanalysis are also described in the text. 相似文献
65.
Hidenobu Kunii 《Ecological Research》1988,3(3):305-318
In order to determine the seasonal growth and biomass ofTrapa japonica Flerov, field observations were carried out at Ojaga-ike Pond, Chiba, Japan, during 1979 and 1980. In spring, the plant showed
exponential growth (c. 0.080 g g−1 day−1) and shoot elongation was as rapid as 10 cm day−1. The plant attained its maximum biomass (380.5±35.1 g m−2) in late August, and about 50% of this was concentrated in the topmost 30-cm stratum (645.7±33.1 g m−3); maximum total stem length exceeded 6m. The plant produced large (500–800 mg per fruit), but small numbers of nut-like fruit
(maximum, 5 fruits per rosette). Defoliation occurred almost linearly with time at a rate of 30.6 leaves m−2 day−1; annual net leaf production was estimated to be about twice as large as the seasonal maximum leaf biomass. While the number
of leaves per rosette showed moderate seasonal change, rosette density, rosette area and leaf dry weight changed considerably
during the year. From the negative log-log correlation between mean total leaf dry weight per rosette and rosette density,
density-dependent rosette growth was assumed. The cause of the wide spread of this species in aquatic habitats is briefly
discussed in terms of its seed size and morphology. 相似文献
66.
Yazawa S Kochibe N Nishimura T Shima C Takai I Adachi M Asao T Hada T Enoki Y Juneja LR 《Glycoconjugate journal》1998,15(9):863-871
A new method for determination of 1,6fucosyltransferase activity has been described. Recently, the disialyl-biantennary undecasaccharide was prepared in high yield from egg yolk [(1996), Carbohydr Lett 2: 137–42]. By treatment of this oligosaccharide with neuraminidase and -galactosidase, we readily obtained an asialo-agalacto-biantennary heptasaccharide (GlcNAc 1,2Man1,6[GlcNAc1,2Man1,3]Man1,4GlcNAc1,4GlcNAc). Using this asialo-agalacto-oligosaccharide as an acceptor, fucosyltransferases from human plasma and extracts of various human hepatoma cell lines were assayed in the presence of GDP-[3H]fucose. The reaction mixture was applied to a column of GlcNAc-binding, Psathyrella velutina lectin coupled gel. All the fucosylated acceptor were bound to the column which was eluted with 50 mM GlcNAc. Structural analyses revealed that only the innermost GlcNAc residue of the acceptor was fucosylated through an 1,6-linkage, and the oligosaccharide prepared could be used as a specific acceptor for 1,6fucosyltransferase. The present method was used to screen plasma 1,6fucosyltransferase in several patient groups, and significantly elevated activities were found in samples from patients with liver diseases, including chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. 相似文献
67.
68.
Ishii T Ito S Kumazawa S Sakurai T Yamaguchi S Mori T Nakayama T Uchida K 《Biochemical and biophysical research communications》2008,371(1):28-32
Malondialdehyde (MDA), a lipid peroxidation product, reacts with lysine residues in proteins. Human serum albumin (HSA) is a major target of MDA-modification of serum proteins. To identify, the modification sites of HSA by MDA in vitro, MDA-treated HSA was digested with a protease and the resulting peptides were subjected to liquid chromatography-tandem mass spectrometry. We identified six peptides, which contained a N-propenal adduct at Lys136, Lys174, Lys240, Lys281, Lys525, and Lys541, and revealed that Lys525 is the most reactive residue for MDA modification. Analysis of electrostatic surface potential of a 3-D model structure of HSA indicates that Lys525 is located at the center of positively charged grooves. The results of this study indicate that the modification of proteins by lipid-derived aldehydes may be influenced by the electrostatic potential of the protein surface. 相似文献
69.
Hahismoto S Yazawa S Asao T Faried A Nishimura T Tsuboi K Nakagawa T Yamauchi T Koyama N Umehara K Saniabadi AR Kuwano H 《Glycoconjugate journal》2008,25(6):531-544
Chemically synthesized sugar-cholestanols with mono-, di-, and tri-saccharides attached to cholestanol showed strong inhibiting activity against the proliferation of colorectal and gastric cancer cells. In contrast, cholestanol without sugar moieties was totally ineffective. Furthermore, when cancer cells were exposed to GlcNAcRbetacholestanol (R=(-) or beta1-3Gal), the compound was rapidly taken up via the lipid rafts/microdomains on the cell surface. The uptake of sugar-cholestanol in mitochondria increased gradually and was followed by the release of cytochrome c from mitochondria and the activation of apoptotic signals through the mitochondrial pathway and the caspase cascade, leading to apoptotic cell death, characterized by DNA ladder formation and nuclear fragmentation. Additionally, the examination of GlcNAcRbetacholestanol in a mouse model of peritoneal dissemination showed a dramatic reduction of tumor growth (P < 0.003) and prolonged mouse survival time (P<0.0001). Based on these observations, we believe that the sugar-cholestanols described here have clinical potential as novel anticancer agents. 相似文献
70.
We developed 12 polymorphic microsatellite markers from a salt-marsh sedge Carex rugulosa. The number of alleles per locus ranged from two to four, with an average of 2.75. The observed and expected heterozygosities ranged from 0.067 to 0.600 and from 0.128 to 0.620, respectively. These simple sequence repeat markers will allow the identification of genets and evaluation of the genetic diversity of C. rugulosa. 相似文献