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排序方式: 共有185条查询结果,搜索用时 15 毫秒
91.
Harris NL Spoerri I Schopfer JF Nembrini C Merky P Massacand J Urban JF Lamarre A Burki K Odermatt B Zinkernagel RM Macpherson AJ 《Journal of immunology (Baltimore, Md. : 1950)》2006,177(9):6256-6262
Following an abrupt transition at birth from the sterile uterus to an environment with abundant commensal and pathogenic microbes, neonatal mammals are protected by maternal Abs at mucosal surfaces. We show in mice that different Ab isotypes work in distinct ways to protect the neonatal mucosal surface. Secretory IgA acts to limit penetration of commensal intestinal bacteria through the neonatal intestinal epithelium: an apparently primitive process that does not require diversification of the primary natural Ab repertoire. In contrast, neonatal protection against the exclusively luminal parasite Heligmosomoides polygyrus required IgG from primed females. This immune IgG could either be delivered directly in milk or retrotransported via neonatal Fc receptor from the neonatal serum into the intestinal lumen to exert its protective effect. 相似文献
92.
Narayan P Subramaniyam Outi RM Väisänen Katrina E Wendel Jaakko AV Malmivuo 《Nonlinear biomedical physics》2010,4(Z1):S4
Background
The electroencephalography (EEG) is an attractive and a simple technique to measure the brain activity. It is attractive due its excellent temporal resolution and simple due to its non-invasiveness and sensor design. However, the spatial resolution of EEG is reduced due to the low conducting skull. In this paper, we compute the potential distribution over the closed surface covering the brain (cortex) from the EEG scalp potential. We compare two methods – L-curve and generalised cross validation (GCV) used to obtain the regularisation parameter and also investigate the feasibility in applying such techniques to N170 component of the visually evoked potential (VEP) data.Methods
Using the image data set of the visible human man (VHM), a finite difference method (FDM) model of the head was constructed. The EEG dataset (256-channel) used was the N170 component of the VEP. A forward transfer matrix relating the cortical potential to the scalp potential was obtained. Using Tikhonov regularisation, the potential distribution over the cortex was obtained.Results
The cortical potential distribution for three subjects was solved using both L-curve and GCV method. A total of 18 cortical potential distributions were obtained (3 subjects with three stimuli each – fearful face, neutral face, control objects).Conclusions
The GCV method is a more robust method compared to L-curve to find the optimal regularisation parameter. Cortical potential imaging is a reliable method to obtain the potential distribution over cortex for VEP data.93.
Bacillus pumilus was isolated from surface-sterilized tissues of the medicinal plant Ocimum sanctum. Scanning electron microscopic (SEM) imaging confirmed the presence of a rod shaped bacterium within the plant tissues. The bacterium was identified as B. pumilus by biochemical analyses and 16S rRNA gene sequencing. In vitro analyses indicate that the isolated strain of B. pumilus was endowed with multiple plant growth promotion (PGP) traits such as phosphate solubilization and the production of indole acetic acid (IAA), siderophore and hydrogen cyanide (HCN). Phosphate solubilization (37.3 μg ml?1) and IAA production (36.7 μg ml?1) by the isolate was found to reach a maximum after 60 h of incubation. Siderophore mediated iron sequestration by B. pumilus may confer a competitive advantage to the host with respect to pathogen inhibition. Siderophore produced by the isolate was found to be of a trihydroxamate type with hexadentate nature. The B. pumilus isolate also exhibited cellulolytic, proteolytic and chitinolytic activity. Cell free supernatant, culture filtrates of the isolate were found to suppress the growth of fungal phytopathogens. The culture filtrate retained its antifungal activity even after exposure to heat. In addition to PGP, the isolate exhibited probiotic properties such as acid tolerance (pH2), bile salt tolerance (2 %), auto-aggregation, antibiotic resistance and the absence of haemolytic activity. These finding suggest the possibility of utilizing this endophytic strain of B. pumilus as a bioinoculant to enhance plant growth and also as a probiotic. 相似文献
94.
RM Christie 《Biotechnic & histochemistry》2013,88(2):51-56
Although the color of indigo is strongly dependent on its environment, it is blue in most commonly encountered situations. Indigo's absorption at such long wavelengths for such a small molecule is unique, and I provide here an overview of the concepts advanced to account for this feature. A traditional valence–bond approach may be used to provide a reasonable qualitative explanation. A more rigorous, quantitative explanation is provided by molecular orbital methods of varying degrees of sophistication and several explanations have been proposed based on these models. Commonly, it is suggested that the important structural unit in determining color is based on the cross-conjugated “H-chromophore” concept. A second closely related explanation describes it as two symmetrically coupled merocyanine chains. Another proposal suggests that the basic chromophore may be interpreted as the aza analogue of two coupled anti aromatic-cyclopentadienyl ions. PiSYSTEM, a commercially available quantum mechanics program, has been used to provide a successful quantitative account of the colors of indigo and indirubin, a red isomer. 相似文献
95.
da Silva FH Pereira VG Yasumura EG Tenório LZ de Carvalho LP Lisboa BC Matsumoto PK Stilhano RS Samoto VY Calegare BF Brandão Lde C D'Almeida V Filippo TR Porcionatto M Toma L Nader HB Valero VB Camassola M Nardi NB Han SW 《Genetic vaccines and therapy》2012,10(1):2-11
Background
Mucopolysaccharidosis type I (MPSI) is caused by a deficiency in alpha-L iduronidase (IDUA), which leads to lysosomal accumulation of the glycosaminoglycans (GAGs) dermatan and heparan sulfate. While the currently available therapies have good systemic effects, they only minimally affect the neurodegenerative process. Based on the neuroprotective and tissue regenerative properties of mesenchymal stem cells (MSCs), we hypothesized that the administration of MSCs transduced with a murine leukemia virus (MLV) vector expressing IDUA to IDUA KO mouse brains could reduce GAG deposition in the brain and, as a result, improve neurofunctionality, as measured by exploratory activity.Methods
MSCs infected with an MLV vector encoding IDUA were injected into the left ventricle of the brain of 12- or 25-month-old IDUA KO mice. The behavior of the treated mice in the elevated plus maze and open field tests was observed for 1 to 2 months. Following these observations, the brains were removed for biochemical and histological analyses.Results
After 1 or 2 months of observation, the presence of the transgene in the brain tissue of almost all of the treated mice was confirmed using PCR, and a significant reduction in GAG deposition was observed. This reduction was directly reflected in an improvement in exploratory activity in the open field and the elevated plus maze tests. Despite these behavioral improvements and the reduction in GAG deposition, IDUA activity was undetectable in these samples. Overall, these results indicate that while the initial level of IDUA was not sustainable for a month, it was enough to reduce and maintain low GAG deposition and improve the exploratory activity for months.Conclusions
These data show that gene therapy, via the direct injection of IDUA-expressing MSCs into the brain, is an effective way to treat neurodegeneration in MPSI mice. 相似文献96.
Sara D'Angelo Jacob Glanville Fortunato Ferrara Leslie Naranjo Cheryl D Gleasner Xiaohong Shen Andrew RM Bradbury Csaba Kiss 《MABS-AUSTIN》2014,6(1):160-172
In vitro selection has been an essential tool in the development of recombinant antibodies against various antigen targets. Deep sequencing has recently been gaining ground as an alternative and valuable method to analyze such antibody selections. The analysis provides a novel and extremely detailed view of selected antibody populations, and allows the identification of specific antibodies using only sequencing data, potentially eliminating the need for expensive and laborious low-throughput screening methods such as enzyme-linked immunosorbant assay. The high cost and the need for bioinformatics experts and powerful computer clusters, however, have limited the general use of deep sequencing in antibody selections. Here, we describe the AbMining ToolBox, an open source software package for the straightforward analysis of antibody libraries sequenced by the three main next generation sequencing platforms (454, Ion Torrent, MiSeq). The ToolBox is able to identify heavy chain CDR3s as effectively as more computationally intense software, and can be easily adapted to analyze other portions of antibody variable genes, as well as the selection outputs of libraries based on different scaffolds. The software runs on all common operating systems (Microsoft Windows, Mac OS X, Linux), on standard personal computers, and sequence analysis of 1–2 million reads can be accomplished in 10–15 min, a fraction of the time of competing software. Use of the ToolBox will allow the average researcher to incorporate deep sequence analysis into routine selections from antibody display libraries. 相似文献
97.
Effects of treatment with IL-2 receptor specific monoclonal antibody in mice. Inhibition of cytotoxic T cell responses but not of T help 总被引:1,自引:0,他引:1
T P Leist M Kohler M Eppler R M Zinkernagel 《Journal of immunology (Baltimore, Md. : 1950)》1989,143(2):628-632
Contribution of IL-2R-bearing activated lymphocytes to antiviral host defense was investigated in C57BL/6 mice by treatment in vivo with IL-2R-specific mAb PC61. When treated on days 0 and 1 with respect to infection with either vaccinia virus, lymphocytic choriomeningitis (LCM) virus (LCMV) or vesicular stomatitis virus, 6-day immune mice had low numbers of CD8+ T cells that were reduced to about 10% of the values found for infected but otherwise untreated controls. In contrast, the number of CD4+ T cells was within normal ranges. Correspondingly, induction of strictly T help-dependent antiviral neutralizing IgG antibody titers remained unaffected by the mAb treatment, whereas generation of antiviral cytotoxic T cell activity was abrogated. Anti-IL-2R treatment of thymectomized mice 14 and 15 days after infection prevented generation of secondary antiviral cytotoxic T cells in restimulation cultures in vitro initiated 24 days later. Treatment with IL-2R-specific mAb was comparable to treatment with CD8-specific mAb in preventing mice to eliminate virus. Because of the involvement of antiviral cytotoxic T cells in disease manifestations, treatment with IL-2R-specific mAb protected mice from lethal LCM after intracerebral infection with LCMV and inhibited the footpad swelling reaction caused by local infection with the same virus. 相似文献
98.
McCoy KD Stoel M Stettler R Merky P Fink K Senn BM Schaer C Massacand J Odermatt B Oettgen HC Zinkernagel RM Bos NA Hengartner H Macpherson AJ Harris NL 《Cell host & microbe》2008,4(4):362-373
Anti-helminth immunity involves CD4+ T cells, yet the precise effector mechanisms responsible for parasite killing or expulsion remain elusive. We now report an essential role for antibodies in mediating immunity against the enteric helminth Heligmosomoides polygyrus (Hp), a natural murine parasite that establishes chronic infection. Polyclonal IgG antibodies, present in naive mice and produced following Hp infection, functioned to limit egg production by adult parasites. Comparatively, affinity-matured parasite-specific IgG and IgA antibodies that developed only after multiple infections were required to prevent adult worm development. These data reveal complementary roles for polyclonal and affinity-matured parasite-specific antibodies in preventing enteric helminth infection by limiting parasite fecundity and providing immune protection against reinfection, respectively. We propose that parasite-induced polyclonal antibodies play a dual role, whereby the parasite is allowed to establish chronicity, while parasite load and spread are limited, likely reflecting the long coevolution of helminth parasites with their hosts. 相似文献
99.
Hypercholesterolemia exacerbates virus-induced immunopathologic liver disease via suppression of antiviral cytotoxic T cell responses 总被引:4,自引:0,他引:4
Ludewig B Jäggi M Dumrese T Brduscha-Riem K Odermatt B Hengartner H Zinkernagel RM 《Journal of immunology (Baltimore, Md. : 1950)》2001,166(5):3369-3376
The immune system has to be optimally balanced to be highly effective against infections with cytopathic microbial pathogens and must guarantee efficient destruction of cells infected with noncytopathic agents while leaving the integrity of noninfected cells largely unaltered. We describe here the effects of genetically induced hypercholesterolemia on cellular immunity in apolipoprotein E (ApoE(-/-)) and low density lipoprotein receptor-deficient (LDLR(-/-)) mice during infection with the hepatotropic lymphocytic choriomeningitis virus WE strain. In both ApoE(-/-) and LDLR(-/-) mice hypercholesterolemia aggravated virus-induced immunopathologic liver disease. ApoE(-/-) mice exhibited a higher susceptibility to virus-induced immunopathology than LDLR(-/-) mice and usually succumbed to immunopathologic disease when infected with high doses of virus. Initial virus spread was not influenced by the hypercholesterolemia, whereas clearance of the virus from spleen and nonlymphoid organs, including liver, was delayed. Activation of antiviral CTL, measured by ex vivo cytotoxicity and IFN-gamma production, and recruitment of specific CTL into blood and liver were impaired in hypercholesterolemic mice, indicating that hypercholesterolemia had a significant suppressive effect on cellular immunity. Taken together, these data provide evidence that hypercholesterolemia suppresses antiviral immune responses, thereby changing the host-virus balance, and can increase susceptibility to acute or chronic and potentially lethal virus-induced immunopathologic disease. These findings impinge on our understanding of hypercholesterolemia as a disease parameter and may explain aspects of the frequent association of persistent pathogens with hypercholesterolemia-induced diseases, such as atherosclerosis. 相似文献
100.
Rapid peptide turnover and inefficient presentation of exogenous antigen critically limit the activation of self-reactive CTL by dendritic cells 总被引:6,自引:0,他引:6
Ludewig B McCoy K Pericin M Ochsenbein AF Dumrese T Odermatt B Toes RE Melief CJ Hengartner H Zinkernagel RM 《Journal of immunology (Baltimore, Md. : 1950)》2001,166(6):3678-3687
This study evaluated to what extent presentation of exogenously acquired self-Ags via MHC class I molecules on DC might contribute to the activation of self-reactive CTL and subsequent development of autoimmune disease. We show here by using the rat insulin promotor lymphocytic choriomeningitis virus glycoprotein model of autoimmune diabetes that the activation of self-reactive CTL by DC after uptake of exogenous Ag is very limited, first by the short half-life of MHC class I-associated peptides on DC in vitro and in vivo, and second by the rather inefficient MHC class I presentation of cell-associated self-Ags by DC. These two mechanisms are probably crucial in establishing high thresholds for the induction of self-reactive CTL that prevent autoimmune sequelae after release of sequestered and previously immunologically ignored tissue Ags. 相似文献