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261.
262.
Denis Rho Ashok Mulchandani John H. T. Luong Anh LeDuy 《Applied microbiology and biotechnology》1988,28(4-5):361-366
Summary Oxygen was essential for the biosynthesis of pullulan by Aureobasidium pullulans. In a growth medium, pullulan yield and synthesis rate were proportional to the oxygen availability. However, under controlled oxygen environment in a non-growth medium, the synthesis rate and the yield of pullulan were inversely proportional to the oxygen tension. A relationship between melanin production and oxygen transfer conditions was also observed. The elapsed time prior to the appearance of the pigment was dependent upon the degree of oxygen availability. 相似文献
263.
N. G. Emel’yanova D. A. Pavlov E. D. Pavlov Luong Thi Bich Thuan Vo Thi Ha 《Journal of Ichthyology》2014,54(1):76-84
We describe anomalies in oocyte structure of manybar goatfish Parupeneus multifasciatus from the coastal zone of southern Central Vietnam. The anomalies are registered in the majority of cells (>80%) from ovarian fragments of several individuals. The abnormal cells are at the periods of maturation, vitellogenesis, and, sometimes, previtellogenesis. Possible effect of pollutants on oocyte morphology is discussed. 相似文献
264.
D Sears P Luong M Yuan G Nteliopoulos Y K S Man J V Melo S Basu 《Cell death & disease》2010,1(11):e93
One proposed strategy to suppress the proliferation of imatinib-resistant cells in chronic myeloid leukemia (CML) is to inhibit key proteins downstream of Bcr-Abl. The PI3K/Akt pathway is activated by Bcr-Abl and is specifically required for the growth of CML cells. To identify targets of this pathway, we undertook a proteomic screen and identified several proteins that differentially bind 14-3-3, dependent on Bcr-Abl kinase activity. An siRNA screen of candidates selected by bioinformatics analysis reveals cold-shock domain protein A (CSDA), shown previously to regulate cell cycle progression in epithelial cells, to be a positive regulator of proliferation in a CML cell line. We show that Akt can phosphorylate the serine 134 residue of CSDA but, downstream of Bcr-Abl activity, this modification is mediated through the activation of MEK/p90 ribosomal S6 kinase (RSK) signaling. Inhibition of RSK, similarly to treatment with imatinib, blocked proliferation specifically in Bcr-Abl-positive leukemia cell lines, as well as cells from CML patients. Furthermore, these primary CML cells showed an increase in CSDA phosphorylation. Expression of a CSDA phospho-deficient mutant resulted in the decrease of Bcr-Abl-dependent transformation in Rat1 cells. Our results support a model whereby phosphorylation of CSDA downstream of Bcr-Abl enhances proliferation in CML cells to drive leukemogenesis. 相似文献
265.
Bertin A McMurray MA Thai L Garcia G Votin V Grob P Allyn T Thorner J Nogales E 《Journal of molecular biology》2010,404(4):711-731
Septins are a conserved family of GTP-binding proteins that assemble into symmetric linear heterooligomeric complexes, which in turn are able to polymerize into apolar filaments and higher-order structures. In budding yeast (Saccharomyces cerevisiae) and other eukaryotes, proper septin organization is essential for processes that involve membrane remodeling, such as the execution of cytokinesis. In yeast, four septin subunits form a Cdc11-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Cdc11 heterooctameric rod that polymerizes into filaments thought to form a collar around the bud neck in close contact with the inner surface of the plasma membrane. To explore septin-membrane interactions, we examined the effect of lipid monolayers on septin organization at the ultrastructural level using electron microscopy. Using this methodology, we have acquired new insights into the potential effect of septin-membrane interactions on filament assembly and, more specifically, on the role of phosphoinositides. Our studies demonstrate that budding yeast septins interact specifically with phosphatidylinositol-4,5-bisphosphate (PIP2) and indicate that the N terminus of Cdc10 makes a major contribution to the interaction of septin filaments with PIP2. Furthermore, we found that the presence of PIP2 promotes filament polymerization and organization on monolayers, even under conditions that prevent filament formation in solution or for mutants that prevent filament formation in solution. In the extreme case of septin complexes lacking the normally terminal subunit Cdc11 or the normally central Cdc10 doublet, the combination of the PIP2-containing monolayer and nucleotide permitted filament formation in vitro via atypical Cdc12-Cdc12 and Cdc3-Cdc3 interactions, respectively. 相似文献
266.
267.
J J O'Shea K B Urdahl H T Luong T M Chused L E Samelson R D Klausner 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(10):3463-3469
Antigen activation of murine T lymphocytes leads to phosphorylation of three subunits of the murine T cell antigen receptor (L.E. Samelson, M.D. Patel, A.M. Weissman, J.B. Harford, and R.D. Klausner. 1986. Cell 46:1083). Two kinases are activated in this process: protein kinase C which leads to phosphorylation of the gamma and, to a lesser extent, the epsilon subunits on serine residues and a tyrosine kinase which phosphorylates the p21 subunit (M.D. Patel, L.E. Samelson, and R.D. Klausner. 1987. J. Biol Chem. 262:5831). We sought to determine whether treatment of these cells with NaF could simulate any of these antigen-induced events. Indeed NaF treatment resulted in breakdown of polyphosphoinositides and production of phosphoinositols. This treatment also resulted in a rise in cytosolic free Ca2+. EGTA failed to block this rise suggesting that NaF liberated intracellular stores of Ca2+. Finally NaF treatment resulted in phosphorylation of the gamma and epsilon chains of the T cell receptor indistinguishable from the effects of phorbol esters. The NaF effect was potentiated by addition of A1Cl3 consistent with the view that the active moiety is A1F4-. The A1F4--induced phosphorylations were abolished in cells in which protein kinase C was depleted by prior treatment with phorbol myristate acetate. All of these observations are compatible with the interpretation that the A1F4- phosphorylation is mediated by protein kinase C. Antigen and anti-receptor antibody-induced receptor serine phosphorylation and phophatidylinositol turnover are blocked by raising intracellular levels of cyclic adenosine monophosphate. In contrast, A1F4--induced effects were insensitive to cyclic adenosine monophosphate. 相似文献
268.
269.
Kao L Kurtz LM Shao X Papadopoulos MC Liu L Bok D Nusinowitz S Chen B Stella SL Andre M Weinreb J Luong SS Piri N Kwong JM Newman D Kurtz I 《The Journal of biological chemistry》2011,286(37):32563-32574
The choroid plexus lining the four ventricles in the brain is where the majority of cerebrospinal fluid (CSF) is produced. The secretory function of the choroid plexus is mediated by specific transport systems that allow the directional flux of nutrients and ions into the CSF and the removal of toxins. Normal CSF dynamics and chemistry ensure that the environment for neural function is optimal. Here, we report that targeted disruption of the Slc4a5 gene encoding the electrogenic sodium bicarbonate cotransporter NBCe2 results in significant remodeling of choroid plexus epithelial cells, including abnormal mitochondrial distribution, cytoskeletal protein expression, and ion transporter polarity. These changes are accompanied by very significant abnormalities in intracerebral ventricle volume, intracranial pressure, and CSF electrolyte levels. The Slc4a5(-/-) mice are significantly more resistant to induction of seizure behavior than wild-type controls. In the retina of Slc4a5(-/-) mice, loss of photoreceptors, ganglion cells, and retinal detachment results in visual impairment assessed by abnormal electroretinogram waveforms. Our findings are the first demonstration of the fundamental importance of NBCe2 in the biology of the nervous system. 相似文献
270.
Scarcelli N Tostain S Vigouroux Y Luong V Baco MN Agbangla C Daïnou O Pham JL 《Genetica》2011,139(8):1055-1064
The relative role of sexual reproduction and mutation in shaping the diversity of clonally propagated crops is largely unknown.
We analyzed the genetic diversity of yam—a vegetatively-propagated crop—to gain insight into how these two factors shape its
diversity in relation with farmers’ classifications. Using 15 microsatellite loci, we analyzed 485 samples of 10 different
yam varieties. We identified 33 different genotypes organized in lineages supported by high bootstrap values. We computed
the probability that these genotypes appeared by sexual reproduction or mutation within and between each lineage. This allowed
us to interpret each lineage as a product of sexual reproduction that has evolved by mutation. Moreover, we clearly noted
a similarity between the genetic structure and farmers’ classifications. Each variety could thus be interpreted as being the
product of sexual reproduction having evolved by mutation. This highly structured diversity of farmer-managed varieties has
consequences for the preservation of yam diversity. 相似文献