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41.
Susan Angell Cinzia G. Lewis Mark J. Buttner Mervyn J. Bibb 《Molecular & general genetics : MGG》1994,244(2):135-143
The glucose kinase gene (glkA-ORF3) of Streptomyces coelicolor A3(2) plays an essential role in glucose utilisation and in glucose repression of a variety of genes involved in the utilisation of alternative carbon sources. These genes include dagA, which encodes an extracellular agarase that permits agar utilisation. Suppressor mutants of glkA-ORF3 deletion strains capable of utilising glucose (Glc+) arise at a frequency of about 10–5 on prolonged incubation. The Glc+ phenotype of the mutants is reversible (at a frequency of about 10–3) and reflects either the activation of a normally silent glucose kinase gene or the modification of an existing sugar kinase. Although the level of glucose kinase activity in the Glc+ supressor mutants is similar to that in the glkA
+ parental strain, glucose repression of dagA remains defective. Expression of the glucose kinase gene of Zymomonas mobilis in glkA-ORF3 mutants restored glucose utilisation, but not glucose repression of dagA. Over-expression of glkA-ORF3 on a high-copy-number plasmid failed to restore glucose repression of dagA in glkA-ORF3 mutants and led to loss of glucose repression of dagA in a glkA
+ strain. These results suggest that glucose phosphorylation itself is not sufficient for glucose repression and that glkA-ORF3 plays a specific regulatory role in triggering glucose repression in S. coelicolor A3(2). 相似文献
42.
Susan Angell Cinzia G. Lewis Mark J. Buttner Mervyn J. Bibb 《Molecular genetics and genomics : MGG》1994,244(2):135-143
The glucose kinase gene (glkA-ORF3) of Streptomyces coelicolor A3(2) plays an essential role in glucose utilisation and in glucose repression of a variety of genes involved in the utilisation of alternative carbon sources. These genes include dagA, which encodes an extracellular agarase that permits agar utilisation. Suppressor mutants of glkA-ORF3 deletion strains capable of utilising glucose (Glc+) arise at a frequency of about 10?5 on prolonged incubation. The Glc+ phenotype of the mutants is reversible (at a frequency of about 10?3) and reflects either the activation of a normally silent glucose kinase gene or the modification of an existing sugar kinase. Although the level of glucose kinase activity in the Glc+ supressor mutants is similar to that in the glkA + parental strain, glucose repression of dagA remains defective. Expression of the glucose kinase gene of Zymomonas mobilis in glkA-ORF3 mutants restored glucose utilisation, but not glucose repression of dagA. Over-expression of glkA-ORF3 on a high-copy-number plasmid failed to restore glucose repression of dagA in glkA-ORF3 mutants and led to loss of glucose repression of dagA in a glkA + strain. These results suggest that glucose phosphorylation itself is not sufficient for glucose repression and that glkA-ORF3 plays a specific regulatory role in triggering glucose repression in S. coelicolor A3(2). 相似文献
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Reovirus-Induced Apoptosis Is Preceded by Increased Cellular Calpain Activity and Is Blocked by Calpain Inhibitors 总被引:6,自引:3,他引:3
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Roberta L. Debiasi Margaret K. T. Squier Bobbi Pike Murry Wynes Terence S. Dermody J. John Cohen Kenneth L. Tyler 《Journal of virology》1999,73(1):695-701
The cellular pathways of apoptosis have not been fully characterized; however, calpain, a cytosolic calcium-activated cysteine protease, has been implicated in several forms of programmed cell death. Reoviruses induce apoptosis both in vitro and in vivo and serve as a model for studying virus-induced cell death. We investigated the potential role of calpain in reovirus-induced apoptosis in vitro by measuring calpain activity as well as evaluating the effects of calpain inhibitors. L929 cells were infected with reovirus type 3 Abney (T3A), and calpain activity, measured as cleavage of the fluorogenic calpain substrate Suc-Leu-Leu-Val-Tyr-AMC, was monitored. There was a 1.6-fold increase in calpain activity in T3A-infected cells compared to mock-infected cells; this increase was completely inhibited by preincubation with calpain inhibitor I (N-acetyl-leucyl-leucyl-norleucinal [aLLN]), an active-site inhibitor. Both aLLN and PD150606, a specific calpain inhibitor that interacts with the calcium-binding site, inhibited reovirus-induced apoptosis in L929 cells by 54 to 93%. Apoptosis induced by UV-inactivated reovirus was also reduced 65 to 69% by aLLN, indicating that inhibition of apoptosis by calpain inhibitors is independent of effects on viral replication. We conclude that calpain activation is a component of the regulatory cascade in reovirus-induced apoptosis. 相似文献
45.
L. Christine Turtzo Matthew D. Budde Dana D. Dean Eric M. Gold Bobbi K. Lewis Lindsay Janes Jacob Lescher Tiziana Coppola Angela Yarnell Neil E. Grunberg Joseph A. Frank 《PloS one》2015,10(5)
Mesenchymal stromal cells secrete a variety of anti-inflammatory factors and may provide a regenerative medicine option for the treatment of traumatic brain injury. The present study investigates the efficacy of multiple intravenous or intracardiac administrations of rat mesenchymal stromal cells or human mesenchymal stromal cells in female rats after controlled cortical impact by in vivo MRI, neurobehavior, and histopathology evaluation. Neither intravenous nor intracardiac administration of mesenchymal stromal cells derived from either rats or humans improved MRI measures of lesion volume or neurobehavioral outcome compared to saline treatment. Few mesenchymal stromal cells (<0.0005% of injected dose) were found within 3 days of last dosage at the site of injury after either delivery route, with no mesenchymal stromal cells being detectable in brain at 30 or 56 days post-injury. These findings suggest that non-autologous mesenchymal stromal cells therapy via intravenous or intracardiac administration is not a promising treatment after focal contusion traumatic brain injury in this female rodent model. 相似文献
46.
Morten Nilsen Asima Lokmic Inga Leena Angell Karin C. Ldrup Carlsen Kai-Hkon Carlsen Guttorm Haugen Gunilla Hedlin Christine Monceyron Jonassen Benjamin J. Marsland Bjrn Nordlund Eva Maria Rehbinder Carina Madelen Saunders Hvard O. Skjerven Lars Snipen Anne Cathrine Staff Cilla Sderhll Riyas Vettukattil Knut Rudi 《Applied and environmental microbiology》2021,87(6)
47.
Patrick H. Kavanagh Hannah J. Haynie Geoff Kushnick Bruno Vilela Ty Tuff Claire Bowern Bobbi S. Low Carol R. Ember Kathryn R. Kirby Carlos A. Botero Michael C. Gavin 《Ecography》2021,44(1):67-74
Land ownership shapes natural resource management and social–ecological resilience, but the factors determining ownership norms in human societies remain unclear. Here we conduct a global empirical test of long‐standing theories from ecology, economics and anthropology regarding potential drivers of land ownership and territoriality. Prior theory suggests that resource defensibility, subsistence strategies, population pressure, political complexity and cultural transmission mechanisms may all influence land ownership. We applied multi‐model inference procedures based on logistic regression to cultural and environmental data from 102 societies, 71 with some form of land ownership and 31 with no land ownership. We found an increased probability of land ownership in mountainous environments, where patchy resources may be more cost effective to defend via ownership. We also uncovered support for the role of population pressure, with a greater probability of land ownership in societies living at higher population densities. Our results also show more land ownership when neighboring societies also practiced ownership. We found less support for variables associated with subsistence strategies and political complexity. 相似文献
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N-4-Pyrimidinyl-1H-indazol-4-amine inhibitors of Lck: indazoles as phenol isosteres with improved pharmacokinetics 总被引:1,自引:0,他引:1
Bamborough P Angell RM Bhamra I Brown D Bull J Christopher JA Cooper AW Fazal LH Giordano I Hind L Patel VK Ranshaw LE Sims MJ Skone PA Smith KJ Vickerstaff E Washington M 《Bioorganic & medicinal chemistry letters》2007,17(15):4363-4368
2,4-Dianilino pyrimidines are well-known inhibitors of tyrosine kinases including lymphocyte specific kinase (Lck). Structure-activity relationships at the 4-position are discussed and rationalised. Examples bearing a 2-methyl-5-hydroxyaniline substituent at the 4-position were especially potent but showed poor oral pharmacokinetics. Replacement of this substituent by 4-amino(5-methyl-1H-indazole) yielded compounds with comparable enzyme potency and improved pharmacokinetic properties. 相似文献