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排序方式: 共有198条查询结果,搜索用时 15 毫秒
131.
Hong-wang Zhang Steven J. Coats Lavanya Bondada Franck Amblard Mervi Detorio Ghazia Asif Emilie Fromentin Sarah Solomon Aleksandr Obikhod Tony Whitaker Nicolas Sluis-Cremer John W. Mellors Raymond F. Schinazi 《Bioorganic & medicinal chemistry letters》2010,20(1):60-64
Based on the promising drug resistance profile and potent anti-HIV activity of β-d-3′-azido-2′,3′-dideoxyguanosine, a series of purine modified nucleosides were synthesized by a chemical transglycosylation reaction and evaluated for their antiviral activity, cytotoxicity, and intracellular metabolism. Among the synthesized compounds, several show potent and selective anti-HIV activity in primary lymphocytes. 相似文献
132.
Jay Lin Vincent Roy Liya Wang Li You Luigi A. Agrofoglio Dominique Deville-Bonne Tamara R. McBrayer Steven J. Coats Raymond F. Schinazi Staffan Eriksson 《Bioorganic & medicinal chemistry》2010,18(9):3261-3269
The pathogenic mycoplasma Ureaplasma parvum (Up) causes opportunistic infections and relies on salvage of nucleosides for DNA synthesis and Up thymidine kinase (UpTK) provides the necessary thymidine nucleotides. The anti-HIV compound 3?-azido-3′-deoxythymidine (AZT) is a good substrate for TK. Methods for a rapid and efficient synthesis of new 3′-α-[1,2,3]triazol-3′-deoxythymidine analogs from AZT under Huisgen conditions are described. Thirteen 3′-analogues were tested with human cytosolic thymidine kinase (hTK1) and UpTK. The new analogs showed higher efficiencies (Km/Vmax values) in all cases with UpTK than with hTK1. Still, hTK1 was preferentially inhibited by 9 out of 10 tested analogs. Structural models of UpTK and hTK1 were constructed and used to explain the kinetic results. Two different binding modes of the nucleosides within the active sites of both enzymes were suggested with one predominating in the bacterial enzyme and the other in hTK1. These results will aid future development of anti-mycoplasma nucleosides. 相似文献
133.
Cyclin E2, a Novel G1 Cyclin That Binds Cdk2 and Is Aberrantly Expressed in Human Cancers 总被引:10,自引:0,他引:10 下载免费PDF全文
Jean M. Gudas Marc Payton Sushil Thukral Eddy Chen Michael Bass Murray O. Robinson Steve Coats 《Molecular and cellular biology》1999,19(1):612-622
A novel cyclin gene was discovered by searching an expressed sequence tag database with a cyclin box profile. The human cyclin E2 gene encodes a 404-amino-acid protein that is most closely related to cyclin E. Cyclin E2 associates with Cdk2 in a functional kinase complex that is inhibited by both p27Kip1 and p21Cip1. The catalytic activity associated with cyclin E2 complexes is cell cycle regulated and peaks at the G1/S transition. Overexpression of cyclin E2 in mammalian cells accelerates G1, demonstrating that cyclin E2 may be rate limiting for G1 progression. Unlike cyclin E1, which is expressed in most proliferating normal and tumor cells, cyclin E2 levels were low to undetectable in nontransformed cells and increased significantly in tumor-derived cells. The discovery of a novel second cyclin E family member suggests that multiple unique cyclin E-CDK complexes regulate cell cycle progression. 相似文献
134.
Cuello M Coats AO Darko I Ettenberg SA Gardner GJ Nau MM Liu JR Birrer MJ Lipkowitz S 《Cell death and differentiation》2004,11(5):527-541
The majority of ovarian cancer cells are resistant to apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Subtoxic concentrations of the semisynthetic retinoid N-(4-hydroxyphenyl)retinamide (4HPR) enhanced TRAIL-mediated apoptosis in ovarian cancer cell lines but not in immortalized nontumorigenic ovarian epithelial cells. The enhancement of TRAIL-mediated apoptosis by 4HPR was not due to changes in the levels of proteins known to modulate TRAIL sensitivity. The combination of 4HPR and TRAIL enhanced cleavage of multiple caspases in the death receptor pathway (including the two initiator caspases, caspase-8 and caspase-9). The 4HPR and TRAIL combination leads to mitochondrial permeability transition, significant increase in cytochrome c release, and increased caspase-9 activation. Caspase-9 may further activate caspase-8, generating an amplification loop. Stable overexpression of Bcl-xL abrogates the interaction between 4HPR and TRAIL at the mitochondrial level by blocking cytochrome c release. As a consequence, a decrease in activation of caspase-9, caspase-8, and TRAIL-mediated apoptosis occurs. These results indicate that the enhancement in TRAIL-mediated apoptosis induced by 4HPR is due to the increase in activation of multiple caspases involving an amplification loop via the mitochondrial-death pathway. These findings offer a promising and novel strategy for the treatment of ovarian cancer. 相似文献
135.
136.
Coats SR Pabón-Peña LM Covington JW Vaughan DE 《Biochemical and biophysical research communications》2002,297(5):1112-1120
The src-suppressed C-kinase substrate, SSeCKS, is now recognized as a key regulator of cell signaling and cytoskeletal dynamics. However, few ligands that control SSeCKS expression have been identified. We report that platelet-derived growth factor-BB (PDGF-BB), lysophosphatidic acid (LPA), and eicosapentaenoic acid (EPA) potently modulate SSeCKS gene expression in cultured smooth muscle (RASM) cells relative to other bioactive ligands tested. In addition, EPA-dependent regulation of SSeCKS expression correlates with distinct changes in cell morphology and adhesion in RASM cells. Independent evidence that ligand-specific control of SSeCKS expression links to the regulation of cell adhesion and morphology was obtained using ras-transformed fibroblasts, KNRK. Sodium butyrate (NaB) upregulates SSeCKS mRNA and protein expression corresponding to increased cell-spreading and adhesion. In addition, ectopic expression of recombinant SSeCKS recapitulates attributes of NaB-induced morphogenesis in KNRK cells. The data provide novel evidence that SSeCKS functions in PDGF-BB-, LPA-, EPA-, and NaB-mediated cell signaling. 相似文献
137.
138.
J. K. Brown S. A. Coats I. D. Bedford P. G. Markham J. Bird D. R. Frohlich 《Biochemical genetics》1995,33(7-8):205-214
Esterase profiles were examined for over 40 populations of the whitefly,Bemisia tabaci, obtained from native and cultivated plant hosts worldwide. Twelve unique electromorphs were identified from distinct populations
concentrated largely in Central America, Africa, and India. One electromorph, type B, has recently been proposed as a separate
species,Bemisia argentifolii, and has recently spread throughout much of the world. When considered with evidence from mating studies and the ability
to induce phytotoxic disorders (squash silverleaf disorder), our data suggest that the single taxonBemisia tabaci may actually represent a species complex. 相似文献
139.
Regulation of dimorphism in Saccharomyces cerevisiae: involvement of the novel protein kinase homolog Elm1p and protein phosphatase 2A. 总被引:15,自引:4,他引:11 下载免费PDF全文
M J Blacketer C M Koehler S G Coats A M Myers P Madaule 《Molecular and cellular biology》1993,13(9):5567-5581
The Saccharomyces cerevisiae genes ELM1, ELM2, and ELM3 were identified on the basis of the phenotype of constitutive cell elongation. Mutations in any of these genes cause a dimorphic transition to a pseudohyphal growth state characterized by formation of expanded, branched chains of elongated cells. Furthermore, elm1, elm2, and elm3 mutations cause cells to grow invasively under the surface of agar medium. S. cerevisiae is known to be a dimorphic organism that grows either as a unicellular yeast or as filamentous cells termed pseudohyphae; although the yeast-like form usually prevails, pseudohyphal growth may occur during conditions of nitrogen starvation. The morphologic and physiological properties caused by elm1, elm2, and elm3 mutations closely mimic pseudohyphal growth occurring in conditions of nitrogen starvation. Therefore, we propose that absence of ELM1, ELM2, or ELM3 function causes constitutive execution of the pseudohyphal differentiation pathway that occurs normally in conditions of nitrogen starvation. Supporting this hypothesis, heterozygosity at the ELM2 or ELM3 locus significantly stimulated the ability to form pseudohyphae in response to nitrogen starvation. ELM1 was isolated and shown to code for a novel protein kinase homolog. Gene dosage experiments also showed that pseudohyphal differentiation in response to nitrogen starvation is dependent on the product of CDC55, a putative B regulatory subunit of protein phosphatase 2A, and a synthetic phenotype was observed in elm1 cdc55 double mutants. Thus, protein phosphorylation is likely to regulate differentiation into the pseudohyphal state. 相似文献
140.
Sebastien Boucle Xiao Lu Leda Bassit Tugba Ozturk Olivia Ollinger Russell Franck Amblard Steven J. Coats Raymond F. Schinazi 《Bioorganic & medicinal chemistry letters》2017,27(4):904-910
New modifications to the scaffold of previously reported HBV capsid assembly effectors such as BAY 41-4109, HAP-12 and GLS4 were explored. The anti-HBV activity in the HepAD38 system, and cytotoxicity profiles of each of the new compounds has been assessed. Among them, five new iodo- and bromo-heteroarylpyrimidines analogs displayed anti-HBV activity in the low micromolar range. 相似文献