全文获取类型
收费全文 | 211篇 |
免费 | 18篇 |
国内免费 | 15篇 |
专业分类
244篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 9篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 12篇 |
2012年 | 14篇 |
2011年 | 16篇 |
2010年 | 13篇 |
2009年 | 9篇 |
2008年 | 15篇 |
2007年 | 10篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有244条查询结果,搜索用时 15 毫秒
81.
Legionella pneumophila, the causative agent of Legionnaires’ disease, is a waterborne bacteria. It can multiply in man-made water systems and infect people who inhale contaminated droplets. We have previously reported a Staphylococcus warneri strain that display an anti-Legionella activity. In this work, we characterized three anti-Legionella peptides that are produced by S. warneri. One peptide, warnericin RK, is original, while the two others are delta-lysin I and delta-lysin II, whose genes were previously described. Due to high sequence similarity of the two delta-lysins, further characterization was performed only on delta-lysin I. Warnericin RK and delta-lysin I displayed the same antibacterial spectrum, which is almost restricted to the Legionella genus. Also, both peptides have a hemolytic activity. These results led to the hypothesis that warnericin RK and delta-lysin I share a similar mode of action, and that Legionella should have a specific feature that may explain the high specificity of these antibacterial peptides. 相似文献
82.
83.
84.
Y. A. Knirel S. N. Senchenkova N. A. Kocharova A. S. J. H. U. Shashkov 《Biochemistry. Biokhimii?a》2001,66(9):1035-1041
O-Specific polysaccharides (OPS) were isolated by mild acid hydrolysis of the lipopolysaccharides (LPS) of strainsof Legionella pneumophila serogroups 2-14, as well as strains Lansing 3 and 16453-92 from newly proposed serogroups. TheOPS were studied by 1H- and 13C-NMR spectroscopy, GLC/mass spectrometry, and chemical modifications (mild alkalineO-deacetylation and conversion of the N-acetimidoyl group into the N-acetyl group). All OPS were found to be ahomopolymer of a 5-acetamidino-7-acetamido-3,5,7,9-tetradeoxynonulosonic acid, which in some strains is 8-O-acetylat-ed. In most strains studied, the monosaccharide has the D-glycero-D-talo configuration and is thus the C4 epimer of legion-aminic acid (4-epilegionaminic acid), which has been previously identified as the monomer in the OPS of L. pneumophilaserogroup 1. Poly(4-epilegionaminic acid) occurs as a minor polysaccharide in serogroups 5 (strain Dallas 1) and 13 and isabsent in serogroups 1 and 7. The chemical basis for serological differentiation of L. pneumophila strains is discussed. 相似文献
85.
Zhang Z Zhou R Sauder JM Tonge PJ Burley SK Swaminathan S 《Journal of molecular biology》2011,406(2):313-324
Fatty acyl-AMP ligase (FAAL) is a new member of a family of adenylate-forming enzymes that were recently discovered in Mycobacterium tuberculosis. They are similar in sequence to fatty acyl-coenzyme A (CoA) ligases (FACLs). However, while FACLs perform a two-step catalytic reaction, AMP ligation followed by CoA ligation using ATP and CoA as cofactors, FAALs produce only the acyl adenylate and are unable to perform the second step. We report X-ray crystal structures of full-length FAAL from Escherichia coli (EcFAAL) and FAAL from Legionella pneumophila (LpFAAL) bound to acyl adenylate, determined at resolution limits of 3.0 and 1.85 Å, respectively. The structures share a larger N-terminal domain and a smaller C-terminal domain, which together resemble the previously determined structures of FAAL and FACL proteins. Our two structures occur in quite different conformations. EcFAAL adopts the adenylate-forming conformation typical of FACLs, whereas LpFAAL exhibits a unique intermediate conformation. Both EcFAAL and LpFAAL have insertion motifs that distinguish them from the FACLs. Structures of EcFAAL and LpFAAL reveal detailed interactions between this insertion motif and the interdomain hinge region and with the C-terminal domain. We suggest that the insertion motifs support sufficient interdomain motions to allow substrate binding and product release during acyl adenylate formation, but they preclude CoA binding, thereby preventing CoA ligation. 相似文献
86.
87.
S.T. Chambers A. Withers K. Dawson T. Anderson J. Williman D. Murdoch A. Scott-Thomas S. Slow 《Letters in applied microbiology》2021,73(5):616-622
Legionella longbeachae has been frequently identified in composted plant material and can cause Legionnaires’ disease (LD). We wanted to determine how frequently L. longbeachae DNA was present on gardeners’ gloves, and how long L. longbeachae could persist on inoculated gloves and masks. Volunteers completed a survey of gardening practices and their gardening gloves were tested for L. longbeachae DNA by qPCR. The persistence of viable L. longbeachae was assessed by timed subcultures after inoculation of gardening gloves and masks. Gloves but not masks were used regularly. L. longbeachae was detected on 11 (14%; 95% CI 8–24%) gloves. Viable organisms were recovered from 25–50% of inoculated cotton, leather and PU coated gloves but not rubber gloves after 8 h incubation. There was a difference in dose-response curve slopes by glove material (P = 0·001) and time to 50% sterility (P = 0·036). There were differences in persistence of L. longbeachae between mask types from analysis of the slopes and 50% sterility on the decay curves (P = 0·042, P < 0·001 respectively). Gardening gloves and masks may act as a vector for transmission of L. longbeachae during gardening. Washing gardening gloves and prompt disposal of masks could reduce risk of LD. 相似文献
88.
89.
Ultra-structure and localisation of formazan formed by human neutrophils and amoebae phagocytosing virulent and avirulent Legionella pneumophila 总被引:1,自引:0,他引:1
Abstract Legionella pneumophila (LP) strains of differing virulence were incubated with a solution of nitroblue-tetrazolium (NBT) at a concentration of 1 mg · ml− in the presence of Acanthamoeba polyphaga or human polymorphonuclear neutrophils (PMN). Reduction of NBT to formazan occurred at a faster rate in the presence of virulent strains. Reduction appeared to be temperature dependent; at 37°C the reaction rate was higher than at 20°C. On microscopic examination, deposits of formazan around Legionella cells were observed inside amoebae similar to those deposited in human neutrophils. Electron microscopy revealed electron-dense particles surrounding virulent legionellae, which appeared to be associated with formazan foundation. Formazan formation inside amoebae may suggest the presence of a respiratory burst against LP, which is more intense with virulent strains. 相似文献
90.
Intracellular pathogens have evolved numerous strategies to manipulate their host cells to survive and replicate in a hostile environment. They often exploit membrane trafficking pathways to enter the cell, establish a replicative niche, avoid degradation and immune response, acquire nutrients and lastly, egress. Recent studies on membrane trafficking exploitation by intracellular pathogens have led to the discovery of novel and fascinating cell biology, including a noncanonical mechanism of ubiquitination and a novel mitophagy receptor. Thus, studying how pathogens target host cell membrane trafficking pathways is not only important for the development of new therapeutics, but also helps understanding fundamental mechanisms of cell biology. 相似文献