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51.
InDrosophila montana andD. littoralis (species of theD. virilis group), females use male courtship song in their mate choice in wild preferring males which produce short and dense sound
pulses (Aspi and Hoikkala, 1995). In the present study these song characters were found to be repeatable among overwintered
males. Male progenies of wild-caught flies reared in the laboratory, and inD. montana also the males collected in wild before overwintering, exhibited very little variation between males in these characters.
Contrary to pulse characters, pulse train characters measured forD. montana song varied significantly between laboratory-reared males. Our findings suggest that inD. montana andD. littoralis song characters playing a part in sexual selection in the wild are more condition dependent than song characters which are
not the direct targets of female choice. 相似文献
52.
Anneli Wennman Ernst H. Oliw Saeid Karkehabadi Yang Chen 《The Journal of biological chemistry》2016,291(15):8130-8139
Lipoxygenases (LOX) are non-heme metal enzymes, which oxidize polyunsaturated fatty acids to hydroperoxides. All LOX belong to the same gene family, and they are widely distributed. LOX of animals, plants, and prokaryotes contain iron as the catalytic metal, whereas fungi express LOX with iron or with manganese. Little is known about metal selection by LOX and the adjustment of the redox potentials of their protein-bound catalytic metals. Thirteen three-dimensional structures of animal, plant, and prokaryotic FeLOX are available, but none of MnLOX. The MnLOX of the most important plant pathogen, the rice blast fungus Magnaporthe oryzae (Mo), was expressed in Pichia pastoris. Mo-MnLOX was deglycosylated, purified to homogeneity, and subjected to crystal screening and x-ray diffraction. The structure was solved by sulfur and manganese single wavelength anomalous dispersion to a resolution of 2.0 Å. The manganese coordinating sphere is similar to iron ligands of coral 8R-LOX and soybean LOX-1 but is not overlapping. The Asn-473 is positioned on a short loop (Asn-Gln-Gly-Glu-Pro) instead of an α-helix and forms hydrogen bonds with Gln-281. Comparison with FeLOX suggests that Phe-332 and Phe-525 might contribute to the unique suprafacial hydrogen abstraction and oxygenation mechanism of Mo-MnLOX by controlling oxygen access to the pentadiene radical. Modeling suggests that Arg-525 is positioned close to Arg-182 of 8R-LOX, and both residues likely tether the carboxylate group of the substrate. An oxygen channel could not be identified. We conclude that Mo-MnLOX illustrates a partly unique variation of the structural theme of FeLOX. 相似文献
53.
54.
Nucleotide Sequence, Genomic Organization, and Chromosomal Localization of Genes Encoding the Human NMDA Receptor Subunits NR3A and NR3B 总被引:3,自引:0,他引:3
The N-methyl-D-aspartate (NMDA) receptors are glutamate-regulated ion channels that are critically involved in important physiological and pathological functions of the mammalian central nervous system. We have identified and characterized the gene encoding the human NMDA receptor subunit NR3A (GRIN3A), as well as the gene (GRIN3B) encoding an entirely novel subunit that we named NR3B, as it is most closely related to NR3A (57.4% identity). GRIN3A localizes to chromosome 9q34, in the region 13-34, and consists of nine coding exons. The deduced protein contains 1115 amino acids and shows 92.7% identity to rat NR3A. GRIN3B localizes to chromosome 19p13.3 and contains, as does the mouse NR3B gene (Grin3b), eight coding exons. The deduced proteins of human and mouse NR3B contain 901 and 900 amino acid residues, respectively (81.6% identity). In situ hybridization shows a widespread distribution of Grin3b mRNA in the brain of the adult rat. 相似文献
55.
Myc regulates keratinocyte adhesion and differentiation via complex formation with Miz1 总被引:3,自引:0,他引:3
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Gebhardt A Frye M Herold S Benitah SA Braun K Samans B Watt FM Elsässer HP Eilers M 《The Journal of cell biology》2006,172(1):139-149
Myc plays a key role in homeostasis of the skin. We show that Miz1, which mediates Myc repression of gene expression, is expressed in the epidermal basal layer. A large percentage of genes regulated by the Myc-Miz1 complex in keratinocytes encode proteins involved in cell adhesion, and some, including the alpha6 and beta1 integrins, are directly bound by Myc and Miz1 in vivo. Using a Myc mutant deficient in Miz1 binding (MycV394D), we show that Miz1 is required for the effects of Myc on keratinocyte responsiveness to TGF-beta. Myc, but not MycV394D, decreases keratinocyte adhesion and spreading. In reconstituted epidermis, Myc induces differentiation and loss of cell polarization in a Miz1-dependent manner. In vivo, overexpression of beta1 integrins restores basal layer polarity and prevents Myc-induced premature differentiation. Our data show that regulation of cell adhesion is a major function of the Myc-Miz1 complex and suggest that it may contribute to Myc-induced exit from the epidermal stem cell compartment. 相似文献
56.
Understanding the interplay between climatic and anthropogenic factors is a major challenge in palaeo-ecology. In particular,
it is often difficult to distinguish anthropogenic and “natural” fire in the charcoal record. In this paper, analysis of fossil
pollen, charcoal, diatoms and isotopic evidence from Mapimbi, a small lake in the Kruger National Park, South Africa, suggests
that for most of the past ca. 700 years, the riverine gallery forests surrounding Mapimbi were primarily influenced by climate,
and benefited during warmer, wetter periods. The transitions between four, statistically different phases in the time-series
data coincide with regional climate records previously constructed from speleothem data, and are consistent with the transition
from the medieval warm period ending in the 14th century a.d. to the cooler, drier conditions prevailing during the little ice age of ca. a.d. 1400–1800. The data also suggest a period of significant, anthropogenic influence after a.d. 1800, when maize was grown and the incidence of localised fires increased. An increase in woody cover in recent decades may
be associated with the management of the area by Kruger National Park. A decline in cultivation occurred in the end of the
20th century linked with changes in socio-political organisation. 相似文献
57.
Jaana Vuosku Suvi Sutela Eila Tillman-Sutela Anneli Kauppi Anne Jokela Tytti Sarjala Hely H?ggman 《Plant signaling & behavior》2009,4(10):928-932
In plants, programmed cell death (PCD) is an important mechanism that controls normal growth and development as well as many defence responses. At present, research on PCD in different plant species is actively carried out due to the possibilities offered by modern methods in molecular biology and the increasing amount of genome data. The pine seed provides a favourable model for PCD because it represents an interesting inheritance of seed tissues as well as an anatomically well-described embryogenesis during which several tissues die via morphologically different PCD processes.Key words: conifer, developmental cell death, embryogenesis, megagametophyte, necrotic cell death, pine, seed development 相似文献
58.
Leili Saarse Eve Niinemets Anneli Poska Siim Veski 《Vegetation History and Archaeobotany》2010,19(1):17-28
Data from 59 sequences studied through pollen analysis were used to examine the decline in Alnus in Estonia during the Iron Age. Between a.d. 300 and 1300, the Alnus pollen frequency declined markedly in 30 records distributed evenly across the investigated area. The beginning of the decline
was time transgressive, coincidental with the start of extensive cultivation, and was frequently connected with the commencement
of rye cultivation and the availability of land suitable for cultivation. The greatest reduction in Alnus abundance occurred during the Late Iron Age between a.d. 900 and 1000. This spatially random asynchrony suggests that one or more factors affected Alnus populations across the whole northern region. Human impact is discussed as a plausible cause of the decline. To determine
the initiation of extensive crop farming in the eastern Baltic area, pollen diagrams from Latvia, Lithuania and the Novgorod
region were also examined. 相似文献
59.
Bergström Lind S Hagner-McWhirter S Elfineh L Molin M Jorsback A Ohman J Pettersson U 《Biochemical and biophysical research communications》2010,401(4):581-585
We describe fluorescence-based 2-D gel electrophoresis methods for visualization of low abundant, cancer relevant tyrosine phosphorylated (pTyr) proteins. The methods investigated were fluorescent Western blotting and two-dimensional difference gel electrophoresis (2-D DIGE) for detection of non-enriched and immunoaffinity enriched pTyr protein patterns. The same anti-phosphotyrosine specific antibody, 4G10, was used for both approaches. The results from fluorescent Western blotting of total proteins and from enriched CyDye DIGE pre-labeled pTyr proteins showed similar down regulation of phosphorylation upon treating of cells from a cancer model system (K562 chronic myeloid leukemia cells) with imatinib. This treatment introduced a known perturbation of phosphorylation that enabled testing of these new approaches to analyze variations in tyrosine phosphorylation levels. Enrichment of pTyr proteins was found highly advantageous for the outcome. Out of a simplified 2-D DIGE experiment of immunoaffinity enriched control and treated pTyr proteins, differential analysis as well as protein identification by mass spectrometry (MS) was possible. 相似文献
60.