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51.
Linli Zhou Xiaoying Tian Cailei Zhu Fangwei Wang Jonathan MG Higgins 《EMBO reports》2014,15(3):273-281
Histone modifications coordinate the chromatin localization of key regulatory factors in mitosis. For example, mitotic phosphorylation of Histone H3 threonine‐3 (H3T3ph) by Haspin creates a binding site for the chromosomal passenger complex (CPC). However, how these histone modifications are spatiotemporally controlled during the cell cycle is unclear. Here we show that Plk1 binds to Haspin in a Cdk1‐phosphorylation‐dependent manner. Reducing Plk1 activity decreases the phosphorylation of Haspin and inhibits H3T3ph, particularly in prophase, suggesting that Plk1 is required for initial activation of Haspin in early mitosis. These studies demonstrate that Plk1 can positively regulate CPC recruitment in mitosis. 相似文献
52.
Frederique M Moret Kim MG van der Wurff-Jacobs Johannes WJ Bijlsma Floris PJG Lafeber Joel AG van Roon 《Arthritis research & therapy》2014,16(6)
Introduction
The aim of this study was to investigate PD-1/PD-L1 involvement in the hyporesponsiveness of rheumatoid arthritis (RA) synovial fluid (SF) CD4 T cells upon stimulation by thymic stromal lymphopoietin (TSLP)–primed CD1c myeloid dendritic cells (mDCs).Methods
Expression of PD-1 on naïve (Tn), central memory (Tcm) and effector memory (Tem) CD4 T cell subsets was assessed by flow cytometry. PD-L1 expression and its regulation upon TSLP stimulation of mDCs from peripheral blood (PB) and SF of RA patients were investigated by quantitative RT-PCR and flow cytometry. The involvement of PD-1/PD-L1 interactions in SF T cell hyporesponsiveness upon (TSLP-primed) mDC activation was determined by cell culture in the presence of PD-1 blocking antibodies, with or without interleukin 7 (IL-7) as a recognized suppressor of PD-1 expression.Results
PD-1 expression was increased on CD4 T cells derived from SF compared with PB of RA patients. TSLP increased PD-L1 mRNA expression in both PB and SF mDCs. PD-L1 protein expression was increased on SF mDCs compared with PB mDCs and was associated with T cell hyporesponsiveness. Blockade of PD-1, as well as IL-7 stimulation, during cocultures of memory T cells and (TSLP-primed) mDCs from RA patients significantly recovered T cell proliferation.Conclusion
SF T cell hyporesponsiveness upon (TSLP-primed) mDC stimulation in RA joints is partially dependent on PD-1/PD-L1 interactions, as PD-1 and PD-L1 are both highly expressed on SF T cells and mDCs, respectively, and inhibiting PD-1 availability restores T cell proliferation. The potential of IL-7 to robustly reverse this hyporesponsiveness suggests that such proinflammatory cytokines in RA joints strongly contribute to memory T cell activation. 相似文献53.
E Del Poggetto M Tanturli N Ben-Califa A Gozzini I Tusa G Cheloni I Marzi MG Cipolleschi Y Kashman D Neumann E Rovida P Dello Sbarba 《Cell cycle (Georgetown, Tex.)》2015,14(19):3146-3154
We previously showed that incubation of chronic myeloid leukemia (CML) cells in very low oxygen selects a cell subset where the oncogenetic BCR/Abl protein is suppressed and which is thereby refractory to tyrosine kinase inhibitors used for CML therapy. In this study, salarin C, an anticancer macrolide extracted from the Fascaplysinopsis sponge, was tested as for its activity on CML cells, especially after their incubation in atmosphere at 0.1% oxygen. Salarin C induced mitotic cycle arrest, apoptosis and DNA damage. Salarin C also concentration-dependently inhibited the maintenance of stem cell potential in cultures in low oxygen of either CML cell lines or primary cells. Surprisingly, the drug also concentration-dependently enforced the maintenance of BCR/Abl signaling in low oxygen, an effect which was paralleled by the rescue of sensitivity of stem cell potential to IM. These results suggest a potential use of salarin C for the suppression of CML cells refractory to tyrosine kinase inhibitors 相似文献
54.
55.
Mário C BarrosoJúnior Guilherme P Esteves Thiago P Nunes Lucia MG Silva Alvaro CD Faria Pedro L Melo 《Biomedical engineering online》2011,10(1):14
Introduction
A novel system that combines a compact mobile instrument and Internet communications is presented in this paper for remote evaluation of tremors. The system presents a high potential application in Parkinson's disease and connects to the Internet through a TCP/IP protocol. Tremor transduction is carried out by accelerometers, and the data processing, presentation and storage were obtained by a virtual instrument. The system supplies the peak frequency (fp), the amplitude (Afp) and power in this frequency (Pfp), the total power (Ptot), and the power in low (1-4 Hz) and high (4-7 Hz) frequencies (Plf and Phf, respectively). 相似文献56.
57.
Approximately 100 strains derived from natural populations of Drosophila
melanogaster were tested for the presence or absence of P- element
sequences by using two molecular probes derived from internal regions of a
full-sized P element. Strains that had been collected from several
continents at varying times during the past 60 years were examined. The
oldest available strains, representing most major geographical regions of
the world, exhibited no detectable hybridization to the P-element probes.
In contrast, all recently collected natural populations that were tested
carried P-element sequences. The earliest appearance of P elements occurred
in collections made during the 1950s and early 1960s in the Americas and
during the late 1960s on other continents. The youngest strains that were
completely devoid of P elements originated in populations sampled during
the mid-1960s in America, but as late as 1974 in populations from the USSR.
There are differences in the patterns of hybridization to the two P-element
probes between populations from different geographical regions. These
differences are consistent with the varying P-M phenotypic properties of
these populations. Taken together with the results of phenotypic tests
reported in earlier studies, the available evidence is consistent with the
hypothesis of a worldwide P-element invasion of D. melanogaster during the
past 30 years and suggests that the putative invasion of the Americas
possibly preceded by approximately a decade that in Europe, Africa, and the
rest of the world.
相似文献
58.
Walter Pfaller Christian Willinger Barbara Stoll Christian Hallbrucker Florian Lang Dieter Hussinger 《Journal of cellular physiology》1993,154(2):248-253
Isolated rat hepatocytes were exposed to hypotonic media (225 mosmol/l) for 5 and 15 min and processed for a quantitative electron microscopic stereologic analysis. Within 5 min of hypotonicity, the hepatocyte volume increased by 25% and thereatter displayed a volume regulatory decrease leading to mean cellular volume, which was 16% above that of controls. Stereologic analysis of the major subcellular compartment, the cytosol, showed an identical change as the whole cell. In contrast to that, the mitochondrial compartment increased in volume by 30% within the first 5 min of exposure and returned by regulatory volume decrease back to values of the isotonic controls after 15 min of hypotonicity. In contrast, hypotonicity (220 mosmol/l)-stimulation of flux through mitochondrial glutaminase and the glycine cleavage enzyme complex, as assessed by 14CO2 production from [1-14C]glutamine or [1-14C]glycine in isolated perfused rat liver persisted throughout a 15-min period of hypotonic exposure. Thus hypotonicity-induced alterations of mitochondrial metabolism apparently do not parallel the time course of mitochondrial volume changes. This suggests that persistent mitochondrial swelling is not required for functional alterations, but that the latter may be triggered by the initial swelling of mitochondria. Hypotonic exposure did not alter the nuclear volume of isolated hepatocytes. Cell membrane surface nearly doubled after 5 min of hypotonic exposure, but returned within 15 min of exposure to values observed in normotonic media. This may reflect the participation of exocytosis in hepatocyte volume regulation. © 1993 Wiley-Liss, Inc. 相似文献
59.
Mitochondrial control-region sequences in two shorebird species, the turnstone and the dunlin, and their utility in population genetic studies 总被引:12,自引:0,他引:12
We determined the mitochondrial control-region sequences of five turnstones
(Arenaria interpres) and three dunlins (Calidris alpina). Comparisons
revealed that the central part (part II) is conserved relative to much more
variable parts at the beginning (part I) and the end (part III). This
pattern of sequence conservation is also found in the control regions of
other vertebrates. The average sequence divergence between turnstone and
dunlin was 21.8% for part I, 7.5% for part II, and 29.5% for part III.
Within-species sequence divergence over the entire control region was much
lower, at 0.9% for turnstones and 2.0% for dunlins. In both shorebird
species, part III contains a repetitive sequence composed only of A and C
nucleotides, which has not been found in the control regions of other
birds. A survey of the part I sequences of 25 turnstones and 25 dunlins
sampled around the world revealed that these species have very different
population genetic structures. Dunlins are not only much more
differentiated in their sequences but also have a strongly subdivided
population genetic structure. Pleistocene vicariant events combined with
strong natal philopatry and high mutation rates of the sequences are likely
responsible for this population genetic subdivision. Conversely, part I
sequences of turnstones are weakly differentiated and are geographically
unstructured. We argue that this is not the result of global gene flow but
that, instead turnstones have recently expanded from a refugial population
that was bottlenecked.
相似文献
60.
The distribution of GM1 ganglioside in developing mouse cerebellum was monitored by indirect immunofluorescent detection of choleragenoid receptors. In frozen sections of cerebellum from mice 5 to 10 days old, fluorescence is observed on granule cells in the inner rows of the external granular layer, in the growing molecular layer, the Purkinje cell layer, and the internal granular layer. In sections of adult mice, fluorescence is restricted to the bodies of Purkinje and internal granule neurons. The percentage of fluorescent dissociated or cultured cerebellar cells increases with the postnatal age of the mouse or the duration of time in vitro. No fluorescence is observed in the absence of choleragenoid or if the test material is extracted with chloroform:methanol. To determine whether the expression of surface GM1 ganglioside in culture is a reflection of a developmental program, mice are injected at particular times with [3H]thymidine and cerebellar cultures processed for simultaneous autoradiography and immunofluorescence. Granule cells from 8-day-old mice having cholera toxin receptors at 20 hr in vitro are a distinct population born 1 day or earlier prior to sacrifice. Cells synthesizing DNA on the day of sacrifice are not fluorescent at 20 hr in vitro. This observation correlates well with immunohistological results showing a lack of fluorescence in the outer proliferative rows of the external granular layer. Therefore GM1 ganglioside is not present on granule cell precursors but is expressed at some time after the cells become postmitotic. GM1 ganglioside is detected on growing parallel fibers in situ and neurites in vitro but not on adult axons, suggesting differential localization at a later stage of development. 相似文献