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81.
Molecular phylogenetic evidence that the phylum Haplosporidia has an alveolate ancestry 总被引:1,自引:0,他引:1
The phylogenetic position of the phylum Haplosporidia among other protists
was investigated with the complete 16S-like rRNA gene sequences from two
species in the phylum: Haplosporidium nelsoni, a parasite of oysters, and
Minchinia teredinis, a parasite of shipworms. Because the lack of obvious
morphological homologies with other protists hampered decisions regarding
taxonomic composition for sequence alignment and phylogenetic analysis, the
complete sequences for these two haplosporidians were directed as search
queries to the blast/ncbi.nlm.nih.gov electronic mail server. The results
of this heuristic similarity search provided a basis for constructing a
preliminary higher-taxonomic-level analysis comparing the haplosporidians
with species from the slime molds, fungi, algae, amoebae, ciliates,
dinoflagellates, and apicomplexans. Maximum parsimony yielded equivocal
results, whereas transversionally weighted parsimony suggested an affinity
with the alveolates (i.e., the ciliates, dinoflagellates, and
apicomplexans). Multiple alignment of the two haplosporidian sequences
against 17 taxa in a secondary analysis focusing on the alveolates and
subsequent parsimony analysis placed the phylum Haplosporidia as a
monophyletic group within the Alveolata and as a taxon of equal rank with
the other three alveolate phyla. The precise placement within the Alveolata
was sensitive to weighting.
相似文献
82.
Nabbe KC van Lent PL Holthuysen AE Sloëtjes AW Koch AE Radstake TR van den Berg WB 《Arthritis research & therapy》2005,7(2):R392-R401
During immune-complex-mediated arthritis (ICA), severe cartilage destruction is mediated by Fcγ receptors (FcγRs) (mainly
FcγRI), cytokines (e.g. IL-1), and enzymes (matrix metalloproteinases (MMPs)). IL-13, a T helper 2 (Th2) cytokine abundantly
found in synovial fluid of patients with rheumatoid arthritis, has been shown to reduce joint inflammation and bone destruction
during experimental arthritis. However, the effect on severe cartilage destruction has not been studied in detail. We have
now investigated the role of IL-13 in chondrocyte death and MMP-mediated cartilage damage during ICA. IL-13 was locally overexpressed
in knee joints after injection of an adenovirus encoding IL-13 (AxCAhIL-13), 1 day before the onset of arthritis; injection
of AxCANI (an empty adenoviral construct) was used as a control. IL-13 significantly increased the amount of inflammatory
cells in the synovial lining and the joint cavity, by 30% to 60% at day 3 after the onset of ICA. Despite the enhanced inflammatory
response, chondrocyte death was diminished by two-thirds at days 3 and 7. The mRNA level of FcγRI, a receptor shown to be
crucial in the induction of chondrocyte death, was significantly down-regulated in synovium. Furthermore, MMP-mediated cartilage
damage, measured as neoepitope (VDIPEN) expression using immunolocalization, was halved. In contrast, mRNA levels of MMP-3,
-9, -12, and -13 were significantly higher and IL-1 protein, which induces production of latent MMPs, was increased fivefold
by IL-13. This study demonstrates that IL-13 overexpression during ICA diminished both chondrocyte death and MMP-mediated
VDIPEN expression, even though joint inflammation was enhanced. 相似文献
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84.
Djie Tjwan Thung Joep de Ligt Lisenka EM Vissers Marloes Steehouwer Mark Kroon Petra de Vries Eline P Slagboom Kai Ye Joris A Veltman Jayne Y Hehir-Kwa 《Genome biology》2014,15(10)
Mobile elements are major drivers in changing genomic architecture and can cause disease. The detection of mobile elements is hindered due to the low mappability of their highly repetitive sequences. We have developed an algorithm, called Mobster, to detect non-reference mobile element insertions in next generation sequencing data from both whole genome and whole exome studies. Mobster uses discordant read pairs and clipped reads in combination with consensus sequences of known active mobile elements. Mobster has a low false discovery rate and high recall rate for both L1 and Alu elements. Mobster is available at http://sourceforge.net/projects/mobster.
Electronic supplementary material
The online version of this article (doi:10.1186/s13059-014-0488-x) contains supplementary material, which is available to authorized users. 相似文献85.
In limulus sperm an actin filament bundle 55 mum in length extends from the acrosomal vacuole membrane through a canal in the nucleus and then coils in a regular fashion around the base of the nucleus. The bundle expands systematically from 15 filaments near the acrosomal vacuole to 85 filaments at the basal end. Thin sections of sperm fixed during stages in spermatid maturation reveal that the filament bundle begins to assemble on dense material attached to the acrosomal vacuole membrane. In micrographs fo these early stages in maturation, short bundles are seen extending posteriorly from the dense material. The significance is that these short, developing bundles have about 85 filaments, suggesting that the 85-filament end of the bundle is assembled first. By using filament bundles isolated and incubated in vitro with G actin from muscle, we can determine the end “preferred” for addition of actin monomers during polymerization. The end that would be associated with the acrosomal vacuole membrane, a membrane destined to be continuous with the plasma membrane, is preferred about 10 times over the other, thicker end. Decoration of the newly polymerized portions of the filament bundle with subfragment 1 of myosin reveals that the arrowheads point away from the acrosomal vacuole membrane, as is true of other actin filament bundles attached to membranes. From these observations we conclude that the bundle is nucleated from the dense material associated with the acrosomal vacuole and that monomers are added to the membrane-associated end. As monomers are added at the dense material, the thick first-made end of the filament bundle is pushed down through the nucleus where, upon reaching the base of the nucleus, it coils up. Tapering is brought about by the capping of the peripheral filaments in the bundle. 相似文献
86.
K van Oers A W Santure I De Cauwer N EM van Bers R PMA Crooijmans B C Sheldon M E Visser J Slate M AM Groenen 《Heredity》2014,112(3):307-316
Linking variation in quantitative traits to variation in the genome is an important, but
challenging task in the study of life-history evolution. Linkage maps provide a valuable
tool for the unravelling of such trait−gene associations. Moreover, they give
insight into recombination landscapes and between-species karyotype evolution. Here we
used genotype data, generated from a 10k single-nucleotide polymorphism (SNP) chip, of
over 2000 individuals to produce high-density linkage maps of the great tit (Parus
major), a passerine bird that serves as a model species for ecological and
evolutionary questions. We created independent maps from two distinct populations: a
captive F2-cross from The Netherlands (NL) and a wild population from the United Kingdom
(UK). The two maps contained 6554 SNPs in 32 linkage groups, spanning 2010 cM and
1917 cM for the NL and UK populations, respectively, and were similar in size and
marker order. Subtle levels of heterochiasmy within and between chromosomes were
remarkably consistent between the populations, suggesting that the local departures from
sex-equal recombination rates have evolved. This key and surprising result would have been
impossible to detect if only one population was mapped. A comparison with zebra finch
Taeniopygia guttata, chicken Gallus gallus and the green anole lizard
Anolis carolinensis genomes provided further insight into the evolution of
avian karyotypes. 相似文献
87.
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90.
Marieke Biegstraaten Ivo N van Schaik Wouter Wieling Frits A Wijburg Carla EM Hollak 《BMC neurology》2010,10(1):38