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91.
Sage PT Varghese LM Martinelli R Sciuto TE Kamei M Dvorak AM Springer TA Sharpe AH Carman CV 《Journal of immunology (Baltimore, Md. : 1950)》2012,188(8):3686-3699
Adaptive immunity requires that T cells efficiently scan diverse cell surfaces to identify cognate Ag. However, the basic cellular mechanisms remain unclear. In this study, we investigated this process using vascular endothelial cells, APCs that possess a unique and extremely advantageous, planar morphology. High-resolution imaging revealed that CD4 memory/effector T cells dynamically probe the endothelium by extending submicron-scale, actin-rich "invadosome/podosome-like protrusions" (ILPs). The intimate intercellular contacts enforced by ILPs consistently preceded and supported T cell activation in response to endothelial MHC class II/Ag. The resulting calcium flux stabilized dense arrays of ILPs (each enriched in TCR, protein kinase C-θ, ZAP70, phosphotyrosine, and HS1), forming what we term a podo-synapse. Similar findings were made using CD8 CTLs on endothelium. Furthermore, careful re-examination of both traditional APC models and professional APCs suggests broad relevance for ILPs in facilitating Ag recognition. Together, our results indicate that ILPs function as sensory organelles that serve as actuators of immune surveillance. 相似文献
92.
Virginia M. Tanis Genesis M. Bacani Jonathan M. Blevitt Christa C. Chrovian Shelby Crawford Aimee De Leon Anne M. Fourie Laurent Gomez Cheryl A. Grice Krystal Herman Aaron M. Kearney Adrienne M. Landry-Bayle Alice Lee-Dutra Jay Nelson Jason P. Riley Alejandro Santillán John J.M. Wiener Xiaohua Xue Arlene L. Young 《Bioorganic & medicinal chemistry letters》2012,22(24):7504-7511
Previously, benzthiazole containing LTA4H inhibitors were discovered that were potent (1–3), but were associated with the potential for a hERG liability. Utilizing medicinal chemistry first principles (e.g., introducing rigidity, lowering c Log D) a new benzthiazole series was designed, congeners of 1–3, which led to compounds 7a, 7c, 12a–d which exhibited LTA4H IC50 = 3–6 nM and hERG Dofetilide Binding IC50 = 8.9–> >10 μM. 相似文献
93.
Neves MP Cravo S Lima RT Vasconcelos MH Nascimento MS Silva AM Pinto M Cidade H Corrêa AG 《Bioorganic & medicinal chemistry》2012,20(1):25-33
Thirty-one 2'-hydroxychalcones were prepared via solid-phase synthesis by base-catalyzed aldol condensation of substituted 2'-hydroxyacetophenones and benzaldehydes. Chalcones were tested for their growth inhibitory activity in three human tumor cell lines (MCF-7, NCI-H460 and A375-C5) using the SRB assay. Results revealed that several of the tested compounds caused a pronounced dose-dependent growth inhibitory effect on the tumor cell lines studied in the low micromolar range. To gain further insight on the cellular mechanism of action of this class of compounds, studies of their effect on cell cycle profile as well as on induction of cellular apoptosis were also carried out. Generally, the tested chalcones interfered with the cell cycle profile and increased the percentage of apoptotic MCF-7 cells. The results here presented may help to identify new chalcone-like structures with optimized cell growth inhibitory activity which may be further tested as potential antitumor agents. 相似文献
94.
Adam Doern Xianjun Cao Arlene Sereno Christopher L. Reyes Angelina Altshuler Flora Huang Cathy Hession Albert Flavier Michael Favis Hon Tran Eric Ailor Melissa Levesque Tracey Murphy Lisa Berquist Susan Tamraz Tracey Snipas Ellen Garber William S. Shestowsky Rachel Rennard Christilyn P. Graff Xiufeng Wu William Snyder Lindsay Cole David Gregson Michael Shields Steffan N. Ho Mitchell E. Reff Scott M. Glaser Jianying Dong Stephen J. Demarest Kandasamy Hariharan 《The Journal of biological chemistry》2009,284(15):10254-10267
95.
Andrew F. Donnell Paul J. Dollings John A. Butera Arlene J. Dietrich Kerri K. Lipinski Afshin Ghavami Warren D. Hirst 《Bioorganic & medicinal chemistry letters》2010,20(7):2163-2167
Substituted pyridazino[4,5-b]indolizines were identified as potent and selective PDE4B inhibitors. We describe the structure–activity relationships generated around an HTS hit that led to a series of compounds with low nanomolar affinity for PDE4B and high selectivity over the PDE4D subtype. 相似文献
96.
The Wnt family of signaling proteins functions in embryonic development and mammalian oncogenesis. It is unknown whether these molecules have a role in normal, postdevelopmental, homeostatic processes. Possessing a putative signal sequence and potential glycosylation sites, Wnt-1 is believed to be secreted and remain associated with the cell surface and extracellular matrix. While it has been suggested that Wnt proteins may target cytoskeletal structures more directly, no definitive studies have identified an intracellular association and function for these molecules. Here, we report that Western blots of lysates from retinoic-acid-differentiated P19 cells and bovine endothelial cells indicate the presence of a 45-kDa Wnt-1 protein. In endothelium, Wnt-1 was present in both the Triton X soluble and the insoluble cell fractions. Immunocytochemical labeling localized Wnt-1 to adherens junctions, codistributing with beta-catenin. Wnt-1 also was detected at actin-rich densities (ARDs) within basal cell regions. In wounded monolayers, ARDs delineated the distal margins of cells undergoing directed migration. Transfection with antisense oligonucleotides to Wnt-1 resulted in reduced cohesion of wound edge cells, abnormal protrusive activity, and random movement. Our data indicate that Wnt-1 protein is present in postdevelopmental endothelial cells where it associates with cytoskeletal elements and may retain function as a tissue polarity gene. 相似文献
97.
The membrane-associated methane monooxygenase (pMMO) and pMMO-NADH:quinone oxidoreductase complex from Methylococcus capsulatus Bath 下载免费PDF全文
Choi DW Kunz RC Boyd ES Semrau JD Antholine WE Han JI Zahn JA Boyd JM de la Mora AM DiSpirito AA 《Journal of bacteriology》2003,185(19):5755-5764
Improvements in purification of membrane-associated methane monooxygenase (pMMO) have resulted in preparations of pMMO with activities more representative of physiological rates: i.e., >130 nmol.min(-1).mg of protein(-1). Altered culture and assay conditions, optimization of the detergent/protein ratio, and simplification of the purification procedure were responsible for the higher-activity preparations. Changes in the culture conditions focused on the rate of copper addition. To document the physiological events that occur during copper addition, cultures were initiated in medium with cells expressing soluble methane monooxygenase (sMMO) and then monitored for morphological changes, copper acquisition, fatty acid concentration, and pMMO and sMMO expression as the amended copper concentration was increased from 0 (approximately 0.3 microM) to 95 microM. The results demonstrate that copper not only regulates the metabolic switch between the two methane monooxygenases but also regulates the level of expression of the pMMO and the development of internal membranes. With respect to stabilization of cell-free pMMO activity, the highest cell-free pMMO activity was observed when copper addition exceeded maximal pMMO expression. Optimization of detergent/protein ratios and simplification of the purification procedure also contributed to the higher activity levels in purified pMMO preparations. Finally, the addition of the type 2 NADH:quinone oxidoreductase complex (NADH dehydrogenase [NDH]) from M. capsulatus Bath, along with NADH and duroquinol, to enzyme assays increased the activity of purified preparations. The NDH and NADH were added to maintain a high duroquinol/duroquinone ratio. 相似文献
98.
Di Mascio M Markowitz M Louie M Hogan C Hurley A Chung C Ho DD Perelson AS 《Journal of virology》2003,77(22):12165-12172
Although intermittent episodes of low-level viremia are often observed in well-suppressed highly active antiretroviral therapy (HAART)-treated patients, the timing and amplitude of viral blips have never been examined in detail. We analyze here the dynamics of viral blips, i.e., plasma VL measurements of >50 copies/ml, in 123 HAART-treated patients monitored for a mean of 2.6 years (range, 5 months to 5.3 years). The mean (+/- the standard deviation) blip frequency was 0.09 +/- 0.11/sample, with about one-third of patients showing no viral blips. The mean viral blip amplitude was 158 +/- 132 human immunodeficiency virus type 1 (HIV-1) RNA copies/ml. Analysis of the blip frequency and amplitude distributions suggest that two blips less than 22 days apart have a significant chance of being part of the same episode of viremia. The data are consistent with a hypothetical model in which each episode of viremia consists of a phase of VL rise, followed by two-phase exponential decay. Thus, the term "viral blip" may be a misnomer, since viral replication appears to be occurring over an extended period. Neither the frequency nor the amplitude of viral blips increases with longer periods of observation, but the frequency is inversely correlated with the CD4(+)-T-cell count at the start of therapy, suggesting that host-specific factors but not treatment fatigue are determinants of blip frequency. 相似文献
99.
Human immunodeficiency virus type 1 induces persistent changes in mucosal and blood gammadelta T cells despite suppressive therapy 总被引:1,自引:0,他引:1 下载免费PDF全文
Poles MA Barsoum S Yu W Yu J Sun P Daly J He T Mehandru S Talal A Markowitz M Hurley A Ho D Zhang L 《Journal of virology》2003,77(19):10456-10467
Gammadelta T cells are primarily found in the gastrointestinal mucosa and play an important role in the first line of defense against viral, bacterial, and fungal pathogens. We sought to examine the impact of human immunodeficiency virus type 1 (HIV-1) infection on mucosal as well as peripheral blood gammadelta T-cell populations. Our results demonstrate that HIV-1 infection is associated with significant expansion of Vdelta1 and contraction of Vdelta2 cell populations in both the mucosa and peripheral blood. Such changes were observed during acute HIV-1 infection and persisted throughout the chronic phase, without apparent reversion after treatment with highly active antiretroviral therapy (HAART). Despite an increase in the expression of CCR9 and CD103 mucosal homing receptors on peripheral blood gammadelta T cells in infected individuals, mucosal and peripheral blood gammadelta T cells appeared to be distinct populations, as reflected by distinct CDR3 length polymorphisms and sequences in the two compartments. Although the underlying mechanism responsible for triggering the expansion of Vdelta1 gammadelta T cells remains unknown, HIV-1 infection appears to have a dramatic impact on gammadelta T cells, which could have important implications for HIV-1 pathogenesis. 相似文献
100.
Buhlmann JE Elkin SK Sharpe AH 《Journal of immunology (Baltimore, Md. : 1950)》2003,170(11):5421-5428
Although costimulation plays an important role in activating naive T cells, its role in negative selection is controversial. By following thymocyte deletion induced by endogenous superantigens in mice lacking B7-1 and/or B7-2, we have identified a role for both B7-1 and B7-2 in negative selection. Studies using CD28-deficient and CD28/CTLA-4-double-deficient mice have revealed that either CD28 or another as yet undefined coreceptor can mediate these B7-dependent signals that promote negative selection. Finally, CTLA-4 delivers signals that inhibit selection, suggesting that CTLA-4 and CD28 have opposing functions in thymic development. Combined, the data demonstrate that B7-1/B7-2-dependent signals help shape the T cell repertoire. 相似文献