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131.
To increase the acceptability of food products containing genetically modified microorganisms it is necessary to provide in an early stage to the consumers that the product is safe and that the product provide a clear benefit to the consumer. To comply with the first requirement a systematic approach to analyze the probability that genetically modified lactic acid bacteria will transform other inhabitants of the gastro-intestinal (G/I) tract or that these lactic acid bacteria will pick up genetic information of these inhabitants has been proposed and worked out to some degree. From this analysis it is clear that reliable data are still missing to carry out complete risk assessment. However, on the basis of present knowledge, lactic acid bacteria containing conjugative plasmids should be avoided. Various studies show that consumers in developed countries will accept these products when they offer to them health or taste benefits or a better keepability. For the developing countries the biggest challenge for scientists is most likely to make indigenous fermented food products with strongly improved microbiological stability due to broad spectra bacteriocins produced by lactic acid bacteria. Moreover, these lactic acid bacteria may contribute to health. 相似文献
132.
133.
A. Verrips Gerry C. H. Steenbergen-Spanjers J. A. F. M. Luyten L. P. W. J. van den Heuvel Antoine Keyser Fons J. M. Gabreëls Ron A. Wevers 《Human genetics》1996,98(6):735-737
This report concerns two new mutations in the sterol 27-hydroxylase gene in two patients with cerebrotendinous xanthomatosis
(CTX). In a Surinam-Creole patient (patient A), a G deletion on position cDNA 546/547 in exon 3 led to a frameshift and the
introduction of a premature termination codon. In a Dutch patient (patient B), a C→T transition at position 496 in exon 3
also led to a premature termination codon. Patient A was homozygous for the mutation, whereas patient B was compound heterozygous,
a C→T transition also being found in exon 6 at position 1204. The two new mutations were confirmed by restriction analysis
with the restriction enzymes FokI and MaeI, respectively.
Received: 24 July 1996 / Revised: 9 August 1996 相似文献
134.
Possible Active Site of the Sweet-tasting Protein Thaumatin 总被引:5,自引:1,他引:4
Epitopes on thaumatin and monellin were studied using the PEPSCAN-technology.The antibodies used were raised against thaumatin. Only antibodiesthat, in an ELISA, both recognized thaumatin and monellin wereused in the PEPSCAN-analyses. On thaumatin two major overlappingepitopes were identified. On monellin no epitopes could be identified.The identified epitope region on thaumatin shares structuralfeatures with various peptide and protein sweeteners. It containsan aspartame-like site which is formed by Asp21 and Phe80, tipsof the two extruding loops KGDAALDAGGR1929 and CKRFGRPP7784,which are spatially positioned next to each other. Furthermore,sub-sequences of the KGDAALDAGGR1929 loop are similarto peptide-sweeteners such as L-Asp-D-Ala- L-Ala-methyl esterand L-Asp-D-Ala-Gly-methyl ester. Since the aspartame-like Asp21-Phe80site and the peptide-sweetener-like sequences are also not presentin non-sweet thaumatin-like proteins it is postulated that theKGDAALDAGGR1929 and CKRFGRPP7784 loop containimportant sweet-taste determinants. This region has previouslynot been implicated as a sweet-taste determinant of thaumatin.Chem. Senses 20: 535543, 1995. 相似文献
135.
Ingeborg A. van Gemeren Wouter Musters Cees A. M. J. J. van den Hondel C. Theo Verrips 《Journal of biotechnology》1995,40(3):155-162
A copy of the cutinase cDNA from Fusarium solani pisi was constructed starting from synthetic oligonucleotides. For this construction three separate cassettes were made, which were subsequently assembled to form the cutinase gene. Heterologous expression of the synthetic cutinase gene and the subsequent secretion of the recombinant enzyme was achieved in Saccharomyces cerevisiae and Aspergillus awamori. 相似文献
136.
Noviandi CT Razzazi E Agus A Böhm J Hulan HW Wedhastri S Maryudhani YB Nuryono Sardjono Leibetseder J 《Mycotoxin Research》2001,17(2):174-177
A survey was conducted between 1998–1999 to evaluate the level of aflatoxin B1 (AfB1) contamination in some selected Indonesian food products, mainly peanuts and peanut products for sale in supermarkets or traditional markets in Yogyakarta, Indonesia. Quantitative analysis was carried out on 118 samples using the ELISA (Enzyme-Linked Immunosorbent Assay) technique. The results indicate that (61.1%) samples were contaminated with AfB1 at range 2.0 to 249.0 μg/kg. Approximately 50% of the baby food products analysed were contaminated with AfB1 and the maximum level found was 7.0 μg/kg. In corn products and fermented products, AfB1 was detected in 66.7 and 50.0% of samples, respectively. A level as high as 5.6 μg/kg of AfB1 was found in the corn and 6.0 μg/kg in fermented product. AfB1 was also detected in all rice products, feed products, and other processed products at levels of up to 7.0, 27.0, and 26.0 μg/kg, respectively. 相似文献
137.
Summary The heat resistance ofCitrobacter freundii NCTC 9750 between 45–65°C in media with various water activities has been determined.At a water activity of nearly 1.00, the Arrhenius plot of the death rate shows a sharp breakpoint at 56.5°C, suggesting the existence of at least two different thermal inactivation processes causing lethality of the bacterial cell. The activation energy below 56.5°C is 0.4186 MJ/mol (100 000 cal/mol), above 56.5°C it is 0.1863 MJ/mol (44 500 cal/mol). After addition of sucrose (1.8 mol/l) or NaCl (0.77 mol/l) to the heating medium, such a breakpoint is not observed. The activation energy for these processes are, for sucrose; 0.2097 MJ/mol, for NaCl; 0.3641 MJ/mol. However, at an NaCl concentration of 1.54 mol/l there is a breakpoint at 53.3°C.The influence of the sucrose concentration on the heat resistance can be described by the formula: ln kS=ln kO–a [sucrose]. Such a simple correlation does not exist for the influence of NaCl or glycerol.The heat inactivation of whole cells ofC. freundii was also measured with a differential scanning calorimeter. The first irreversible conformation change took place at 323 K, the main conformation change at 343 K. 相似文献
138.
I. A. van Gemeren A. Beijersbergen W. Musters R. J. Gouka C. A. M. J. J. van den Hondel C. T. Verrips I. A. van Gemeren 《Applied microbiology and biotechnology》1996,45(6):755-763
A synthetic derivative of the cutinase cDNA of Fusarium solani pisi was expressed in Aspergillus awamori using the A. awamori endoxylanase II (exlA) promoter and terminator. The influence of the origin of the pre-sequence and the presence of a pro-sequence on the efficiency
of extracellular cutinase production was analysed in single-copy transformants containing an expression cassette integrated
at the pyrG locus. Transformants containing a construct encoding a direct, in-frame fusion of the xylanase pre-peptide to the mature
cutinase showed a 2-fold higher cutinase production level compared to strains containing constructs with an additional cutinase
pro-peptide. The effect of multicopy integration of the expression cassette on cutinase production was analysed in strains
with different numbers of a cutinase construct containing its own pre-prosequence. The multicopy strains showed a 6- to 12-fold
increased production of extracellular cutinase relative to the single-copy strains. No linear dose response relation to the
number of expression cassettes present in the strains was observed. The amount of active enzyme produced by the strains correlated
with the amount of cutinase-specific mRNA, suggesting that cutinase overproduction is not limited at the level of translation
or secretion.
Received: 3 August 1995/Received revision: 20 December 1995/Accepted: 8 January 1996 相似文献
139.