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31.
The specific activity of urease, nitrogenase, hialuronidase and neuraminidase in Y. pseudotuberculosis grown in different culture media and at different temperature has been studied. These enzymes have been found capable of functioning at both relatively low (2-8 degrees C) and high (37 degrees C) temperatures. The thermoadaptive properties of Y. pseudotuberculosis within a wide range of temperatures are ensured by the constant presence of isoenzymes, functioning only at low temperatures or only at high temperatures, in the microbial cells. Low temperature in combination with a definite culture medium triggers the activity of certain enzymatic systems, which explains, to some extent, the biochemical mechanisms of the psychrophilic properties of Y. pseudotuberculosis. 相似文献
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Background
The Neotropical ovenbird-woodcreeper family (Furnariidae) is an avian group characterized by exceptionally diverse ecomorphological adaptations. For instance, members of the family are known to construct nests of a remarkable variety. This offers a unique opportunity to examine whether changes in nest design, accompanied by expansions into new habitats, facilitates diversification. We present a multi-gene phylogeny and age estimates for the ovenbird-woodcreeper family and use these results to estimate the degree of convergent evolution in both phenotype and habitat utilisation. Furthermore, we discuss whether variation in species richness among ovenbird clades could be explained by differences in clade-specific diversification rates, and whether these rates differ among lineages with different nesting habits. In addition, the systematic positions of some enigmatic ovenbird taxa and the postulated monophyly of some species-rich genera are evaluated. 相似文献36.
37.
Zaĭtseva EA Ermolaeva SA Somov GP 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2006,(4):42-45
The collection of 76 Listeria monocytogenes strains isolated from humans, animals and food products was screened with PCR to reveal genes, which encode invasion factors of the internalin family. Obtained results demonstrated the correlation between the strain specific polymorphism of the revealed internalin genes and the source of the strain. 相似文献
38.
Fernanda Abreu Mauricio E Cant?o Marisa F Nicolás Fernando G Barcellos Viviana Morillo Luiz GP Almeida Fabrícia F do Nascimento Christopher T Lefèvre Dennis A Bazylinski Ana Tereza R de Vasconcelos Ulysses Lins 《The ISME journal》2011,5(10):1634-1640
Magnetosomes are prokaryotic organelles produced by magnetotactic bacteria that consist of nanometer-sized magnetite (Fe3O4) or/and greigite (Fe3S4) magnetic crystals enveloped by a lipid bilayer membrane. In magnetite-producing magnetotactic bacteria, proteins present in the magnetosome membrane modulate biomineralization of the magnetite crystal. In these microorganisms, genes that encode for magnetosome membrane proteins as well as genes involved in the construction of the magnetite magnetosome chain, the mam and mms genes, are organized within a genomic island. However, partially because there are presently no greigite-producing magnetotactic bacteria in pure culture, little is known regarding the greigite biomineralization process in these organisms including whether similar genes are involved in the process. Here using culture-independent techniques, we now show that mam genes involved in the production of magnetite magnetosomes are also present in greigite-producing magnetotactic bacteria. This finding suggest that the biomineralization of magnetite and greigite did not have evolve independently (that is, magnetotaxis is polyphyletic) as once suggested. Instead, results presented here are consistent with a model in which the ability to biomineralize magnetosomes and the possession of the mam genes was acquired by bacteria from a common ancestor, that is, the magnetotactic trait is monophyletic. 相似文献
39.
S. N. Tamkovich N. V. Yunusova M. N. Stakheeva A. K. Somov A. E. Frolova N. A. Kiryushina S. G. Afanasyev A. E. Grigor’eva P. P. Laktionov I. V. Kondakova 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2017,11(3):291-295
A simple approach for isolation of exosomes from blood plasma samples has been proposed. Using this approach it is possible to obtain highly purified preparations of microvesicles no larger than 100 nm. The presence of different subpopulations of exosomes isolated by this method has been recognized in the blood plasma of healthy donors and cancer patients. Universal markers CD9, CD24, and CD81 are applicable for routine typing of exosomes isolated from blood plasma samples. 相似文献
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JS Agerholm O Andersen MB Almskou C Bendixen J Arnbjerg GP Aamand US Nielsen F Panitz AH Petersen 《Acta veterinaria Scandinavica》2004,45(3):133
To investigate the congenital complex vertebral malformation syndrome (CVM) in Holstein calves, two breeding studies were
performed including 262 and 363 cows, respectively. Cows were selected from the Danish Cattle Database based on pedigree and
insemination records. Selected cows were progeny of sires with an established heterozygous CVM genotype and pregnant after
insemination with semen from another sire with heterozygous CVM genotype. Following calving the breeders should state, if
the calf was normal and was requested to submit dead calves for necropsy. In both studies, significantly fewer CVM affected
calves than expected were obtained; a finding probably reflecting extensive intrauterine mortality in CVM affected foetuses.
The findings illustrate increased intrauterine mortality as a major potential bias in observational studies of inherited disorders. 相似文献