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11.
12.
Rebecca C Mueller Fabiana S Paula Babur S Mirza Jorge LM Rodrigues Klaus Nüsslein Brendan JM Bohannan 《The ISME journal》2014,8(7):1548-1550
Understanding the interactions among microbial communities, plant communities and soil properties following deforestation could provide insights into the long-term effects of land-use change on ecosystem functions, and may help identify approaches that promote the recovery of degraded sites. We combined high-throughput sequencing of fungal rDNA and molecular barcoding of plant roots to estimate fungal and plant community composition in soil sampled across a chronosequence of deforestation. We found significant effects of land-use change on fungal community composition, which was more closely correlated to plant community composition than to changes in soil properties or geographic distance, providing evidence for strong links between above- and below-ground communities in tropical forests. 相似文献
13.
Three satellite DNA families were identified in three species of burying
beetles, Nicrophorus orbicollis, N. marginatus, and N. americanus. Southern
hybridization and nucleotide sequence analysis of individual randomly
cloned repeats shows that these satellite DNA families are highly abundant
in the genome, are composed of unique repeats, and are species-specific.
The repeats do not have identifiable core elements or substructures that
are similar in all three families, and most interspecific sequence
similarity is confined to homopolymeric runs of A and T. Satellite DNA from
N. marginatus and N. americanus show single-base-pair indels among repeats,
but single-nucleotide substitutions characterize most of the repeat
variability. Although the repeat units are of similar lengths (342, 350,
and 354 bp) and A + T composition (65%, 71%, and 71%, respectively), the
average nucleotide divergence among sequenced repeats is very low (0.18%,
1.22%, and 0.71%, respectively). Transition/transversion ratios from the
consensus sequence are 0.20, 0.69, and 0.70, respectively.
相似文献
14.
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16.
LM Harris L Blank RP Desai NE Welker ET Papoutsakis 《Journal of industrial microbiology & biotechnology》2001,27(5):322-328
The effect of solR inactivation on the metabolism of Clostridium acetobutylicum was examined using fermentation characterization and metabolic flux analysis. The solR-inactivated strain (SolRH) of this study had a higher rate of glucose utilization and produced higher solvent concentrations
(by 25%, 14%, and 81%, respectively, for butanol, acetone, and ethanol) compared to the wild type. Strain SolRH(pTAAD), carrying
a plasmid-encoded copy of the bifunctional alcohol/aldehyde dehydrogenase gene (aad) used in butanol production, produced even higher concentrations of solvents (by 21%, 45%, and 62%, respectively, for butanol,
acetone, and ethanol) than strain SolRH. Clarithromycin used for strain SolRH maintenance during SolRH(pTAAD) fermentations
did not alter product formation; however, tetracycline used for pTAAD maintenance resulted in 90% lower solvent production.
Journal of Industrial Microbiology & Biotechnology (2001) 27, 322–328.
Received 12 September 2000/ Accepted in revised form 21 July 2001 相似文献
17.
A parsimony analysis was performed on restriction sites at the Hba-ps4
pseudogene locus within one of four inversions associated with mouse t
haplotypes. The results suggest that all t haplotypes form a monophyletic
group and that the in (17)4 inversion originated before the radiation of
the Mus musculus species complex but after the divergence of the lineages
leading to M. spretus, M. abbotti, and M. hortulanus. A time frame based on
the evolutionary rate of mouse pseudogenes places the origin of this t
haplotype inversion at 1.5 Mya, or approximately 1.5 Myr after the origin
of the more proximal t complex inversion, in (17)2. The accumulated
evidence indicates that complete t haplotypes have been assembled in a
stepwise manner, with each of these inversions occurring on separate
chromosomal lineages and at different evolutionary times. In addition, the
evolutionary relationships of pseudogene sequences resulting from genetic
exchange between wild-type and t haplotype alleles were examined. Analysis
of sequences from the 5' and 3' sides of a putative site of recombination
resulted in cladograms with different topologies. The implications for
hypotheses concerning the evolutionary forces acting on t haplotypes and
their rapid propagation throughout worldwide populations of mice are
discussed.
相似文献
18.
Molecular evidence for the rapid propagation of mouse t haplotypes from a single, recent, ancestral chromosome 总被引:11,自引:0,他引:11
Silver LM; Hammer M; Fox H; Garrels J; Bucan M; Herrmann B; Frischauf AM; Lehrach H; Winking H; Figueroa F 《Molecular biology and evolution》1987,4(5):473-482
Mouse t haplotypes are variant forms of chromosome 17 that exist at high
frequencies in worldwide populations of two species of commensal mice. To
determine both the relationship of t haplotypes to each other and the
species within which they exist, 35 representative t haplotypes were
analyzed by means of 10 independent molecular probes, including five DNA
clones and five polypeptide spots identified by means of two- dimensional
gel electrophoresis. All of the tested haplotypes were found to share
restriction fragments and polypeptide spots that are absent in mice
carrying wild-type forms of chromosome 17. This observation provides the
first direct evidence that all of the known t haplotypes are descendents of
a single ancestral chromosome. The absence of variation among t haplotypes
could mean that this ancestral chromosome existed relatively recently, in
which case it would be necessary to postulate introgressions of t
haplotypes across species lines to explain their presence in both Mus
domesticus and M. musculus. Alternatively, it is possible that the
ancestral chromosome existed prior to the split between M. domesticus and
M. musculus and that, by chance, our probes fail to detect polymorphisms
that exist among the t haplotypes. A further result of our analysis is the
characterization of a partial t haplotype in a wild population of Israeli
mice.
相似文献
19.
Membrane resistance change of the frog taste cells in response to water and Nacl 总被引:2,自引:0,他引:2 下载免费PDF全文
The electrical properties of the frog taste cells during gustatory stimulations with distilled water and varying concentrations of NaCl were studied with intracellular microelectrodes. Under the Ringer adaptation of the tongue, two types of taste cells were distinguished by the gustatory stimuli. One type, termed NaCl-sensitive (NS) cells, responded to water with hyperpolarizations and responded to concentrated NaCl with depolarizations. In contrast, the other type of cells, termed water-sensitive (WS) cells, responded to water depolarizations and responded to concentrated NaCl with hyperpolarizations. The membrane resistance of both taste cell types increased during the hyperpolarizing receptor potentials and decreased during the depolarizing receptor potentials, Reversal potentials for the depolarizing and hyperpolarizing responses in each cell type were a few millivolts positive above the zero membrane potential. When the tongue was adapted with Na-free Ringer solution for 30 min, the amplitude of the depolarizing responses in the NS cells reduced to 50% of the control value under normal Ringer adaptation. On the basis of the present results, it is concluded (a) that the depolarizing responses of the NS and WS cells under the Ringer adaptation are produced by the permeability increase in some ions, mainly Na+ ions across the taste cell membranes, and (b) that the hyperpolarizing responses of both types of taste cells are produced by a decrease in the cell membrane permeability to some ions, probably Na+ ions, which is slightly enhanced during the Ringer adaptation. 相似文献
20.
Eleonore S Köhler Selvakumari Sankaranarayanan Christa J van Ginneken Paul van Dijk Jacqueline LM Vermeulen Jan M Ruijter Wouter H Lamers Elisabeth Bruder 《BMC developmental biology》2008,8(1):107