全文获取类型
收费全文 | 110篇 |
免费 | 9篇 |
国内免费 | 3篇 |
专业分类
122篇 |
出版年
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 3篇 |
2012年 | 9篇 |
2011年 | 6篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有122条查询结果,搜索用时 0 毫秒
61.
Lonneke Smeding Jan Willem Kuiper Frans B Pl?tz Martin CJ Kneyber AB Johan Groeneveld 《Respiratory research》2013,14(1):92
Background
Mechanical ventilation (MV) may cause ventilator-induced lung injury (VILI) and may thereby contribute to fatal multiple organ failure. We tested the hypothesis that injurious MV of lipopolysaccharide (LPS) pre-injured lungs induces myocardial inflammation and further dysfunction ex vivo, through calcium (Ca2+)-dependent mechanism.Materials and methods
N = 35 male anesthetized and paralyzed male Wistar rats were randomized to intratracheal instillation of 2 mg/kg LPS or nothing and subsequent MV with lung-protective settings (low tidal volume (Vt) of 6 mL/kg and 5 cmH2O positive end-expiratory pressure (PEEP)) or injurious ventilation (high Vt of 19 mL/kg and 1 cmH2O PEEP) for 4 hours. Myocardial function ex vivo was evaluated in a Langendorff setup and Ca2+ exposure. Key mediators were determined in lung and heart at the mRNA level.Results
Instillation of LPS and high Vt MV impaired gas exchange and, particularly when combined, increased pulmonary wet/dry ratio; heat shock protein (HSP)70 mRNA expression also increased by the interaction between LPS and high Vt MV. For the heart, C-X-C motif ligand (CXCL)1 and Toll-like receptor (TLR)2 mRNA expression increased, and ventricular (LV) systolic pressure, LV developed pressure, LV +dP/dtmax and contractile responses to increasing Ca2+ exposure ex vivo decreased by LPS. High Vt ventilation aggravated the effects of LPS on myocardial inflammation and dysfunction but not on Ca2+ responses.Conclusions
Injurious MV by high Vt aggravates the effects of intratracheal instillation of LPS on myocardial dysfunction, possibly through enhancing myocardial inflammation via pulmonary release of HSP70 stimulating cardiac TLR2, not involving Ca2+ handling and sensitivity. 相似文献62.
Preparation and Characterization of Neisseria meningitidis Mutants Deficient in Production of the Human Lactoferrin-Binding Proteins LbpA and LbpB 总被引:3,自引:0,他引:3 下载免费PDF全文
Pathogenic members of the family Neisseriaceae produce specific receptors facilitating iron acquisition from transferrin (Tf) and lactoferrin (Lf) of their mammalian host. Tf receptors are composed of two outer membrane proteins, Tf-binding proteins A and B (TbpA and TbpB; formerly designated Tbp1 and Tbp2, respectively). Although only a single Lf-binding protein, LbpA (formerly designated Lbp1), had previously been recognized, we recently identified additional bacterial Lf-binding proteins in the human pathogens Neisseria meningitidis and Moraxella catarrhalis and the bovine pathogen Moraxella bovis by a modified affinity isolation technique (R. A. Bonnah, R.-H. Yu, and A. B. Schryvers, Microb. Pathog. 19:285–297, 1995). In this report, we characterize an open reading frame (ORF) located immediately upstream of the N. meningitidis B16B6 lbpA gene. Amino acid sequence comparisons of various TbpBs with the product of the translated DNA sequence from the upstream ORF suggests that the region encodes the Lf-binding protein B homolog (LbpB). The LbpB from strain B16B6 has two large stretches of negatively charged amino acids that are not present in the various transferrin receptor homologs (TbpBs). Expression of the recombinant LbpB protein as a fusion with maltose binding protein demonstrated functional Lf-binding activity. Studies with N. meningitidis isogenic mutants in which the lbpA gene and the ORF immediately upstream of lbpA (putative lbpB gene) were insertionally inactivated demonstrated that LbpA, but not LbpB, is essential for iron acquisition from Lf in vitro. 相似文献
63.
Siti Mutripah Maria Dyah Nur Meinita Ji-Young Kang Gwi-Taek Jeong AB Susanto Romanus Edy Prabowo Yong-Ki Hong 《Journal of applied phycology》2014,26(1):687-693
Seaweeds, particularly species of red macroalgae, are promising resources for bioethanol production because of their exceptionally high carbohydrate content. Of 20 seaweeds evaluated, Palmaria palmata (Rhodymenia palmata) contained the highest carbohydrate content (469.8 mg g?1 seaweed) with a carrageenan content of 354 mg g?1 seaweed. Such a high carrageenan content makes the high-volume production of bioethanol feasible. Acid hydrolysis of P. palmata in 0.4 M H2SO4 at 125 °C for 25 min released 27 mg of glucose, 218.4 mg of reducing sugars, and 127.6 mg of galactose per gram of seaweed. Ethanol fermentation of these hydrolysis products using an inoculum concentration of 1.5 mg mL?1 at 30 °C and 72 h in a shaking incubator at 130 rpm yielded 17.3 mg of ethanol per gram of seaweed. 相似文献
64.
M?nica G Campiteli Frederico M Soriani Iran Malavazi Osame Kinouchi Carlos AB Pereira Gustavo H Goldman 《BMC bioinformatics》2009,10(1):270
Background
Microarray techniques have become an important tool to the investigation of genetic relationships and the assignment of different phenotypes. Since microarrays are still very expensive, most of the experiments are performed with small samples. This paper introduces a method to quantify dependency between data series composed of few sample points. The method is used to construct gene co-expression subnetworks of highly significant edges. 相似文献65.
Patrícia Picciarelli-Lima André G Oliveira Adelina M Reis Evanguedes Kalapothakis Germán AB Mahecha Rex A Hess Cleida A Oliveira 《Reproductive biology and endocrinology : RB&E》2006,4(1):51-10
Background
Fluid homeostasis is critical for normal function of the male reproductive tract and aquaporins (AQP) play an important role in maintenance of this water and ion balance. Several AQPs have been identified in the male, but their regulation is not fully comprehended. Hormonal regulation of AQPs appears to be dependent on the steroid in the reproductive tract region. AQP9 displays unique hormonal regulation in the efferent ductules and epididymis, as it is regulated by both estrogen and dihydrotestosterone (DHT) in the efferent ductules, but only by DHT in the initial segment epididymis. Recent data have shown that a metabolite of DHT, 5-alpha-androstane-3-beta-17-beta-diol (3-beta-diol), once considered inactive, is also present in high concentrations in the male and indeed has biological activity. 3-beta-diol does not bind to the androgen receptor, but rather to estrogen receptors ER-alpha and ER-beta, with higher affinity for ER-beta. The existence of this estrogenic DHT metabolite has raised the possibility that estradiol may not be the only estrogen to play a major role in the male reproductive system. Considering that both ER-alpha and ER-beta are highly expressed in efferent ductules, we hypothesized that the DHT regulation of AQP9 could be due to the 3-beta-diol metabolite. 相似文献66.
Bacteria that inhabit the respiratory and genitourinary tracts of mammals encounter an iron-deficient environment on the mucosal surface where iron is complexed by the host iron-binding proteins transferrin and lactoferrin. Lactoferrin is also present in high concentrations at sites of inflammation where the cationic anti-microbial peptide lactoferricin is produced by proteolysis of lactoferrin. Several members of the Neisseriaceae and Moraxellaceae families express surface receptors, capable of specifically binding host lactoferrin and extracting the iron from lactoferrin as a source of iron for growth. The receptor is comprised of an integral outer membrane protein, lactoferrin binding protein A (LbpA), and a largely exposed surface lipoprotein, lactoferrin binding protein B (LbpB). LbpA is essential for mediating growth using lactoferrin as a sole iron source whereas LbpB only plays a facilitating role. LbpB, with the presence of a large tract of negatively charged residues, appears to protect the bacterial cell from the bactericidal effects of the lactoferricin. The lactoferrin receptors in these species appear to be essential for survival and thus may serve as potential vaccine targets. 相似文献
67.
68.
Calmettes C Yu RH Silva LP Curran D Schriemer DC Schryvers AB Moraes TF 《The Journal of biological chemistry》2011,286(14):12683-12692
Pathogenic bacteria acquire the essential element iron through specialized uptake pathways that are necessary in the iron-limiting environments of the host. Members of the Gram-negative Neisseriaceae and Pasteurellaceae families have adapted to acquire iron from the host iron binding glycoprotein, transferrin (Tf), through a receptor complex comprised of transferring-binding protein (Tbp) A and B. Because of the critical role they play in the host, these surface-exposed proteins are invariably present in clinical isolates and thus are considered prime vaccine targets. The specific interactions between TbpB and Tf are essential and ultimately might be exploited to create a broad-spectrum vaccine. In this study, we report the structure of TbpBs from two porcine pathogens, Actinobacillus pleuropneumoniae and suis. Paradoxically, despite a common Tf target, these swine related TbpBs show substantial sequence variation in their Tf-binding site. The TbpB structures, supported by docking simulations, surface plasmon resonance and hydrogen/deuterium exchange experiments with wild-type and mutant TbpBs, explain why there are structurally conserved elements within TbpB homologs despite major sequence variation that are required for binding Tf. 相似文献
69.
Kristof Theys Koen Deforche Jurgen Vercauteren Pieter Libin David AMC van de Vijver Jan Albert Birgitta ?sj? Claudia Balotta Marie Bruckova Ricardo J Camacho Bonaventura Clotet Suzie Coughlan Zehava Grossman Osamah Hamouda Andrzei Horban Klaus Korn Leondios G Kostrikis Claudia Kücherer Claus Nielsen Dimitrios Paraskevis Mario Poljak Elisabeth Puchhammer-Stockl Chiara Riva Lidia Ruiz Kirsi Liitsola Jean-Claude Schmit Rob Schuurman Anders S?nnerborg Danica Stanekova Maja Stanojevic Daniel Struck Kristel Van Laethem Annemarie MJ Wensing Charles AB Boucher Anne-Mieke Vandamme 《Retrovirology》2012,9(1):1-13
Background
Bone marrow stromal cell antigen 2 (BST-2) is a cellular factor that restricts the egress of viruses such as human immunodeficiency virus (HIV-1) from the surface of infected cells, preventing infection of new cells. BST-2 is variably expressed in most cell types, and its expression is enhanced by cytokines such as type I interferon alpha (IFN-??). In this present study, we used the beta-retrovirus, mouse mammary tumor virus (MMTV) as a model to examine the role of mouse BST-2 in host infection in vivo.Results
By using RNA interference, we show that loss of BST-2 enhances MMTV replication in cultured mammary tumor cells and in vivo. In cultured cells, BST-2 inhibits virus accumulation in the culture medium, and co-localizes at the cell surface with virus structural proteins. Furthermore, both scanning electron micrograph (SEM) and transmission electron micrograph (TEM) show that MMTV accumulates on the surface of IFN??-stimulated cells.Conclusions
Our data provide evidence that BST-2 restricts MMTV release from naturally infected cells and that BST-2 is an antiviral factor in vivo. 相似文献70.
We describe a new scaffold-free three-dimensional (3D) cell culture model using cholesteryl ester based lyotropic liquid crystal (LC) substrates. Keratinocytes were deposited randomly on the LC surface where they self-assembled into 3D microtissues or keratinospheroids. The cell density required to form spheroids was optimized. We investigated cell viability using dead/live cell assays. The adhesion characteristics of cells within the microtissues were determined using histological sectioning and immunofluorescence staining. Fourier transform infrared spectroscopy (FTIR) was used to characterize the biochemistry of the keratinospheroids. We found that both cells and microtissues could migrate on the LC surface. The viability study indicated approximately 80% viability of cells in the microtissues up to 20 days of culture. Strong intercellular adhesion was observed in the stratification of the multi-layered microspheroids using field emission-scanning electron microscopy (FE-SEM) and histochemical staining. The cytoskeleton and vinculins of the cells in the microtissues were expressed diffusely, but the microtissues were enriched with lipids and nucleic acids, which indicates close resemblance to the conditions in vivo. The basic 3D culture model based on LC may be used for cell and microtissue migration studies in response to cytochemical treatment. 相似文献