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971.
Allain B Jarray R Borriello L Leforban B Dufour S Liu WQ Pamonsinlapatham P Bianco S Larghero J Hadj-Slimane R Garbay C Raynaud F Lepelletier Y 《Cellular signalling》2012,24(1):214-223
Recently, we identified a new Vascular Endothelial Growth Factor (VEGF)-A165-induced gene Phactr-1, (Phosphatase Actin Regulator-1). We reported that Phactr-1 gene silencing inhibited tube formation in human umbilical endothelial cells (HUVECs) indicating a key role for Phactr-1 in tubulogenesis in vitro. In this study, we investigated the role of Phactr-1 in several cellular processes related to angiogenesis. We found that neuropilin-1 (NRP-1) and VEGF-R1 depletion inhibited Phactr-1 mRNA expression while NRP-2 and VEGF-R2 depletion had no effect. We described a new interaction site of VEGF-A165 to VEGF-R1 in peptides encoded by exons 7 and 8 of VEGF-A165. The specific inhibition of VEGF-A165 binding on NRP-1 and VEGF-R1 by ERTCRC and CDKPRR peptides decreased the Phactr-1 mRNA levels in HUVECs indicating that VEGF-A165-dependent regulation of Phactr-1 expression required both NRP-1 and VEGF-R1 receptors. In addition, upon VEGFA165-stimulation Phactr-1 promotes formation and maintenance of cellular tubes through NRP-1 and VEGFR1. Phactr-1 was previously identified as protein phosphatase 1 (PP1) α-interacting protein that possesses actin-binding domains. We showed that Phactr-1 depletion decreased PP1 activity, disrupted the fine-tuning of actin polymerization and impaired lamellipodial dynamics. Taken together our results strongly suggest that Phactr-1 is a key component in the angiogenic process. 相似文献
972.
Bucciantini M Nosi D Forzan M Russo E Calamai M Pieri L Formigli L Quercioli F Soria S Pavone F Savistchenko J Melki R Stefani M 《FASEB journal》2012,26(2):818-831
The interaction of amyloid aggregates with the cell plasma membrane is currently considered among the basic mechanisms of neuronal dysfunction in amyloid neurodegeneration. We used amyloid oligomers and fibrils grown from the yeast prion Sup35p, responsible for the specific prion trait [PSI(+)], to investigate how membrane lipids modulate fibril interaction with the membranes of cultured H-END cells and cytotoxicity. Sup35p shares no homology with endogenous mammalian polypeptide chains. Thus, the generic toxicity of amyloids and the molecular events underlying cell degeneration can be investigated without interference with analogous polypeptides encoded by the cell genome. Sup35 fibrils bound to the cell membrane without increasing its permeability to Ca(2+). Fibril binding resulted in structural reorganization and aggregation of membrane rafts, with GM1 clustering and alteration of its mobility. Sup35 fibril binding was affected by GM1 or its sialic acid moiety, but not by cholesterol membrane content, with complete inhibition after treatment with fumonisin B1 or neuraminidase. Finally, cell impairment resulted from caspase-8 activation after Fas receptor translocation on fibril binding to the plasma membrane. Our observations suggest that amyloid fibrils induce abnormal accumulation and overstabilization of raft domains in the cell membrane and provide a reasonable, although not unique, mechanistic and molecular explanation for fibril toxicity. 相似文献
973.
974.
Cantini F Savino S Scarselli M Masignani V Pizza M Romagnoli G Swennen E Veggi D Banci L Rappuoli R 《The Journal of biological chemistry》2006,281(11):7220-7227
GNA1870, a 28-kDa surface-exposed lipoprotein of Neisseria meningitidis recently discovered by reverse vaccinology, is one of the most potent antigens of Meningococcus and a promising candidate for a universal vaccine against a devastating disease. Previous studies of epitope mapping and genetic characterization identified residues critical for bactericidal response within the C-terminal domain of the molecule. To elucidate the conformation of protective epitopes, we used NMR spectroscopy to obtain the solution structure of the immunodominant 18-kDa C-terminal portion of GNA1870. The structure consists of an eight-stranded antiparallel beta-barrel overlaid by a short alpha-helix with an unstructured N-terminal end. Residues previously shown to be important for antibody recognition were mapped on loops facing the same ridge of the molecule. The sequence similarity of GNA1870 with members of the bacterial transferrin receptor family allows one to predict the folding of this class of well known bacterial antigens, providing the basis for the rational engineering of high affinity B cell epitopes. 相似文献
975.
Fiaschi T Cozzi G Raugei G Formigli L Ramponi G Chiarugi P 《The Journal of biological chemistry》2006,281(32):22983-22991
Redox sensitivity of actin toward an exogenous oxidative stress has recently been reported. We report here the first evidence of in vivo actin redox regulation by a physiological source of reactive oxygen species, specifically those species generated by integrin receptors during cell adhesion. Actin oxidation takes place via the formation of a mixed disulfide between cysteine 374 and glutathione; this modification is essential for spreading and for cytoskeleton organization. Impairment of actin glutathionylation, either through GSH depletion or expression of the C374A redox-insensitive mutant, greatly affects cell spreading and the formation of stress fibers, leading to inhibition of the disassembly of the actinomyosin complex. These data suggest that actin glutathionylation is essential for cell spreading and cytoskeleton organization and that it plays a key role in disassembly of actinomyosin complex during cell adhesion. 相似文献
976.
Muresanu L Pristovsek P Löhr F Maneg O Mukrasch MD Rüterjans H Ludwig B Lücke C 《The Journal of biological chemistry》2006,281(20):14503-14513
977.
Functional conservation of MADS-box factors controlling floral organ identity in rice and Arabidopsis 总被引:9,自引:0,他引:9
Studies on MADS-box genes in Arabidopsis and other higher eudicotyledonous flowering plants have shown that they are key regulators of flower development. Since Arabidopsis and monocotyledonous rice are distantly related plant species it is interesting to investigate whether the floral organ identity factors have been conserved in their functions, and if not, to understand the differences. Arabidopsis and rice are very suitable for these studies since they are both regarded as models for plant functional genomics. Both their genomes are sequenced and tools are available for the analysis of gene function. These developments have accelerated experiments and increased our knowledge on rice gene function. Therefore it is the right moment to perform a comparative analysis on MADS-box factors controlling floral organ identity as reported in this review. 相似文献
978.
Senerovic L Stankovic N Spizzo P Basso A Gardossi L Vasiljevic B Ljubijankic G Tisminetzky S Degrassi G 《Biotechnology and bioengineering》2006,93(2):344-354
A complete, integrated process for the production of an innovative formulation of penicillin G acylase from Providencia rettgeri(rPAC(P.rett))of industrial applicability is reported. In order to improve the yield of rPAC, the clone LN5.5, carrying four copies of pac gene integrated into the genome of Pichia pastoris, was constructed. The proteinase activity of the recombinant strain was reduced by knockout of the PEP4 gene encoding for proteinase A, resulting in an increased rPAC(P.rett) activity of approximately 40% (3.8 U/mL vs. 2.7 U/mL produced by LN5.5 in flask). A high cell density fermentation process was established with a 5-day methanol induction phase and a final PAC activity of up to 27 U/mL. A single step rPAC(P.rett) purification was also developed with an enzyme activity yield of approximately 95%. The novel features of the rPAC(P.rett) expressed in P.pastoris were fully exploited and emphasized through the covalent immobilization of rPAC(P.rett). The enzyme was immobilized on a series of structurally correlated methacrylic polymers, specifically designed and produced for optimizing rPAC(P.rett) performances in both hydrolytic and synthetic processes. Polymers presenting aminic functionalities were the most efficient, leading to formulations with higher activity and stability (half time stability >3 years and specific activity ranging from 237 to 477 U/g (dry) based on benzylpenicillin hydrolysis). The efficiency of the immobilized rPAC(P.rett) was finally evaluated by studying the kinetically controlled synthesis of beta-lactam antibiotics (cephalexin) and estimating the synthesis/hydrolysis ratio (S/H), which is a crucial parameter for the feasibility of the process. 相似文献
979.
Guaragnella N Pereira C Sousa MJ Antonacci L Passarella S Côrte-Real M Marra E Giannattasio S 《FEBS letters》2006,580(30):6880-6884
Yeast cells lacking the metacaspase-encoding gene YCA1 (Δyca1) were compared with wild-type (WT) cells with respect to the occurrence, nature and time course of acetic-acid triggered death. We show that Δyca1 cells undergo programmed cell death (PCD) with a rate lower than that of the WT and that PCD in WT cells is caused at least in part by the caspase activity of Yca1p. Since in Δyca1 cells this effect is lost, but z-VAD-fmk does not prevent both WT and Δyca1 cell death, PCD in WT cells occurs via a Yca1p caspase and a non-caspase route with similar characteristics. 相似文献
980.
T cell antiviral effector function is not dependent on CXCL10 following murine coronavirus infection
Stiles LN Hardison JL Schaumburg CS Whitman LM Lane TE 《Journal of immunology (Baltimore, Md. : 1950)》2006,177(12):8372-8380
The chemokine CXCL10 is expressed within the CNS in response to intracerebral infection with mouse hepatitis virus (MHV). Blocking CXCL10 signaling results in increased mortality accompanied by reduced T cell infiltration and increased viral titers within the brain suggesting that CXCL10 functions in host defense by attracting T cells into the CNS. The present study was undertaken to extend our understanding of the functional role of CXCL10 in response to MHV infection given that CXCL10 signaling has been implicated in coordinating both effector T cell generation and trafficking. We show that MHV infection of CXCL10(+/+) or CXCL10(-/-) mice results in comparable levels of T cell activation and similar numbers of virus-specific CD4+ and CD8+ T cells. Subsequent analysis revealed no differences in T cell proliferation, IFN-gamma secretion by virus-specific T cells, or CD8+ T cell cytolytic activity. Analysis of chemokine receptor expression on CD4+ and CD8+ T cells obtained from MHV-immunized CXCL10(+/+) and CXCL10(-/-) mice revealed comparable levels of CXCR3 and CCR5, which are capable of responding to ligands CXCL10 and CCL5, respectively. Adoptive transfer of splenocytes acquired from MHV-immunized CXCL10(-/-) mice into MHV-infected RAG1(-/-) mice resulted in T cell infiltration into the CNS, reduced viral burden, and demyelination comparable to RAG1(-/-) recipients of immune CXCL10(+/+) splenocytes. Collectively, these data imply that CXCL10 functions primarily as a T cell chemoattractant and does not significantly influence T cell effector response following MHV infection. 相似文献