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Genetic mouse models are an important tool in the study of mammalian neural tube closure (Gray & Ross, 2009; Ross, 2010). However, the study of mouse embryos in utero is limited by our inability to directly pharmacologically manipulate the embryos in isolation from the effects of maternal metabolism on the reagent of interest. Whether using a small molecule, recombinant protein, or siRNA, delivery of these substances to the mother, through the diet or by injection will subject these unstable compounds to a variety of bodily defenses that could prevent them from reaching the embryo. Investigations in cultures of whole embryos can be used to separate maternal from intrinsic fetal effects on development.Here, we present a method for culturing mouse embryos using highly enriched media in a roller incubator apparatus that allows for normal neural tube closure after dissection (Crockett, 1990). Once in culture, embryos can be manipulated using conventional in vitro techniques that would not otherwise be possible if the embryos were still in utero. Embryo siblings can be collected at various time points to study different aspects of neurulation, occurring from E7-7.5 (neural plate formation, just prior to the initiation of neurulation) to E9.5-10 (at the conclusion of cranial fold and caudal neuropore closure, Kaufman, 1992). In this protocol, we demonstrate our method for dissecting embryos at timepoints that are optimal for the study of cranial neurulation. Embryos will be dissected at E8.5 (approx. 10-12 somities), after the initiation of neural tube closure but prior to embryo turning and cranial neural fold closure, and maintained in culture till E10 (26-28 somities), when cranial neurulation should be complete. 相似文献
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Cell proliferation is a fundamental event essential for plant organogenesis and contributes greatly to the final organ size. Although the control of cell proliferation in plants has been extensively studied, how the plant sets the cell number required for a single organ is largely elusive. Here, we describe the Arabidopsis SMALL ORGAN 4 (SMO4) that functions in the regulation of cell proliferation rate and thus final organ size. The smo4 mutant exhibits a reduced size of organs due to the decreased cell number, and further analysis reveals that such phenotype results from a retardation of the cell cycle progression during organ development. SMO4 encodes a homolog of NUCLEOLAR PROTEIN 53 (NOP53) in Saccharomyces cerevisiae and is expressed primarily in tissues undergoing cell proliferation. Nevertheless, further complementation tests show that SMO4 could not rescue the lethal defect of NOP53 mutant of S. cerevisiae. These results define SMO4 as an important regulator of cell proliferation during organ growth and suggest that SMO4 might have been evolutionarily divergent from NOP53. 相似文献
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Large scale electrophysiological recordings from neuronal ensembles offer the opportunity to investigate how the brain orchestrates the wide variety of behaviors from the spiking activity of its neurons. One of the most effective methods to monitor spiking activity from a large number of neurons in multiple local neuronal circuits simultaneously is by using silicon electrode arrays1-3.Action potentials produce large transmembrane voltage changes in the vicinity of cell somata. These output signals can be measured by placing a conductor in close proximity of a neuron. If there are many active (spiking) neurons in the vicinity of the tip, the electrode records combined signal from all of them, where contribution of a single neuron is weighted by its ''electrical distance''. Silicon probes are ideal recording electrodes to monitor multiple neurons because of a large number of recording sites (+64) and a small volume. Furthermore, multiple sites can be arranged over a distance of millimeters, thus allowing for the simultaneous recordings of neuronal activity in the various cortical layers or in multiple cortical columns (Fig. 1). Importantly, the geometrically precise distribution of the recording sites also allows for the determination of the spatial relationship of the isolated single neurons4. Here, we describe an acute, large-scale neuronal recording from the left and right forelimb somatosensory cortex simultaneously in an anesthetized rat with silicon probes (Fig. 2). 相似文献
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S. Park K.J. Hwang H. Chu S.H. Park S.K. Shim Y.S. Choi J.S. Kim M.Y. Park 《Letters in applied microbiology》2010,50(5):445-451
Aims: The objective of this study was to evaluate recombinant 56‐kDa outer membrane protein as a potential inhibitor to infection from Orientia tsutsugamushi. Methods and Results: The 56‐kDa protein was cloned and expressed in an Escherichia coli system, and the degree of target cell attachment to immobilized 56‐kDa protein was measured in a cell adhesion assay. The results showed that the 56‐kDa protein has an ability to attach HeLa cells. Furthermore, treatment of target cells with a truncated 56‐kDa 1–418 (amino acid residues) protein inhibited target cell infection by O. tsutsugamushi, demonstrated with an indirect immunofluorescence antibody assay. Conclusions: The truncated 56‐kDa protein (a.a. 1–418) plays an important role in O. tsutsugamushi infection, and the 56‐kDa protein could be useful and effective in the inhibition of O. tsutsugamushi attachment and infection. Significance and Impact of the Study: The attachment of the 56‐kDa protein to target cells was directly determined by in vitro adherence test, and the invasion of target cells by O. tsutsugamushi was inhibited by treating the target cells with a truncated 56‐kDa protein. 相似文献
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Yumi Ueki Michael A Hadders Melanie B Weisser Isha Nasa Paula SoteloParrilla Lauren E Cressey Tanmay Gupta Emil P T Hertz Thomas Kruse Guillermo Montoya A Arockia Jeyaprakash Arminja Kettenbach Susanne M A Lens Jakob Nilsson 《EMBO reports》2021,22(7)
The shugoshin proteins are universal protectors of centromeric cohesin during mitosis and meiosis. The binding of human hSgo1 to the PP2A‐B56 phosphatase through a coiled‐coil (CC) region mediates cohesion protection during mitosis. Here we undertook a structure function analysis of the PP2A‐B56‐hSgo1 complex, revealing unanticipated aspects of complex formation and function. We establish that a highly conserved pocket on the B56 regulatory subunit is required for hSgo1 binding and cohesion protection during mitosis in human somatic cells. Consistent with this, we show that hSgo1 blocks the binding of PP2A‐B56 substrates containing a canonical B56 binding motif. We find that PP2A‐B56 bound to hSgo1 dephosphorylates Cdk1 sites on hSgo1 itself to modulate cohesin interactions. Collectively our work provides important insight into cohesion protection during mitosis. 相似文献
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目的
了解广东省三级医院护
理人力资源的配置现状,探讨更合理的配置对策。方法 自行设计问卷,对广东省21个地市的76所三级医院护理人力资源数量、护理人力资源内部结构、人员流失、支持保障系统情况等现状进行研究分析。结果 8所(13.33%)医院未成立临床支持中心; 23所(38.33%)医院普通病房实际床位总数与普通病房护士总数比不达标;职业性别比例严重失衡,男性仅占2.61%;34岁及以下护士占76.38%;大专及以下学历占78.61%;高级职称占4.65%;近年离职比由3.62%上升至5.08%。结论 广东省三级医院护理人员非护理工作负担较重;人力资源总量相对不足,队伍结构欠合理;护士人力流失逐年增加。建议优化三级医院护理人力配置,重视临床服务指标,建立并完善后勤保障系统,积极开展护士岗位改革等是适应社会高速发展需求和护理学科专业化的重要举措。 相似文献