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101.
Mitochondrial DNA sequence variation can be used to infer honeybee evolutionary relationships. In this study, DNA sequence diversity of the mitochondrial 16s rDNA region was investigated in 112 honeybees from 15 populations in Turkey, which is mainly populated with Apis mellifera anatoliaca, A. m. caucasica, and A. m. meda. The study revealed 11 haplotypes for this segment, with 13 variable sites and nine parsimony informative sites. The haplotypes were not discriminated according to their geographical locations in a neighbor-joining dendrogram based on 16s rDNA sequences available in Genbank, but all the haplotypes obtained in this study are clustered with published haplotypes such as A. mellifera TAS (AF214666) and A. m. ligustica (EF116868) and with some unpublished Genbank records (HQ318928, HQ318934, and HQ318938). This study expands the knowledge of the mitochondrial 16s rDNA region, and it presents the first comprehensive sequence analysis of this region in Turkish honeybees. 相似文献
102.
Phosphorylation mutants of JC virus agnoprotein are unable to sustain the viral infection cycle
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Many eukaryotic and viral regulatory proteins are known to undergo posttranslational modifications including phosphorylation, which plays a critical role in many aspects of cell function. Previous studies from our and other laboratories indicated that the JC virus (JCV) late regulatory protein, agnoprotein, plays an important role in the JCV life cycle. Agnoprotein contains several potential phosphorylation sites, including Ser7, Ser11, and Thr21, which are potential targets for the serine/threonine-specific protein kinase C (PKC). In this study, we investigated the functional significance of these phosphorylation sites for the activity of agnoprotein. In vitro and in vivo kinase assays demonstrated that agnoprotein is a target for phosphorylation by PKC. In addition, each of the PKC phosphorylation sites was mutated to Ala singly and in combination, and the effects of these mutations on the JCV life cycle were analyzed. Although the expression of each mutant agnoprotein was detectable during the infection cycle, virus containing each of these mutations failed to propagate. These results contrast with those obtained with an agnoprotein start codon point (Pt) mutant where agnoprotein expression was completely inhibited. The Pt mutant was viable but replicates less efficiently than the wild type (WT). Moreover, conservative substitutions at PKC phosphorylation sites (Ser7, Ser11, and Thr21 to Asp) resulted in a viable virus, which further demonstrate the importance of these sites on agnoprotein function. Further analysis of the mutants by viral release assay and electron microscopy studies revealed that viral particles were efficiently released from infected cells and morphologically indistinguishable from those of WT but were deficient in DNA content. This may account for the defective propagation of the mutants. These results imply that phosphorylated forms of agnoprotein may have essential functions in the viral life cycle and serve as potential targets for therapeutic interventions to limit JCV propagation and JCV-induced diseases. 相似文献
103.
Ilhan Onaran Gulgun S. Guven Sule Beyhan Ozda Gonul Kanigur Suphi Vehid 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2006,611(1-2):1-8
Metformin (1-(diaminomethylidene)-3,3-dimethyl-guanidine), which is the most commonly prescribed oral antihyperglycaemic drug in the world, was reported to have several antioxidant properties such as the inhibition of advanced glycation end-products. In addition to its use in the treatment of diabetes, it has been suggested that metformin may be a promising anti-aging agent. The present work was aimed at assessing the possible protective effects of metformin against DNA-damage induction by oxidative stress in vitro. The effects of metformin were compared with those of N-acetylcysteine (NAC). For this purpose, peripheral blood lymphocytes from aged (n = 10) and young (n = 10) individuals were pre-incubated with various concentrations of metformin (10–50 μM), followed by incubation with 15 μM cumene hydroperoxide (CumOOH) for 48 h, under conditions of low oxidant level, which do not induce cell death. Protection against oxidative DNA damage was evaluated by use of the Comet assay and the cytokinesis-block micronucleus technique. Changes in the levels of malondialdehyde + 4-hydroxy-alkenals, an index of oxidative stress, were also measured in lymphocytes. At concentrations ranging from 10 μM to 50 μM, metformin did not protect the lymphocytes from DNA damage, while 50 μM NAC possessed an effective protective effect against CumOOH-induced DNA damage. Furthermore, NAC, but not metformin, inhibited DNA fragmentation induced by CumOOH. In contrast to the lack of protection against oxidative damage in lymphocyte cultures, metformin significantly protected the cells from lipid peroxidation in both age groups, although not as effective as NAC in preventing the peroxidative damage at the highest doses. Within the limitations of this study, the results indicate that pharmacological concentrations of metformin are unable to protect against DNA damage induced by a pro-oxidant stimulus in cultured human lymphocytes, despite its antioxidant properties. 相似文献
104.
The effect of temperature on the adsorption of metanil yellow (MY) (acidic) and methylene blue (MB) (basic) by poplar sawdust was investigated. In addition, the amounts of NaHCO(3), Na(2)CO(3), NaOH and C(2)H(5)ONa adsorbed by 1g of poplar sawdust to determine its surface acidity were also determined. Kinetical data obtained at different temperatures (293 K, 313 K and 333 K) for the adsorption of each dyestuff by poplar sawdust were applied to the pseudo first-order, the pseudo second-order and the intraparticle diffusion equations, and the rate constants of first-order adsorption (k(1)), the rate constants of second-order adsorption (k(2)) and intraparticle diffusion rate constants (k(p)) at these temperatures were calculated, respectively. In addition, isothermal data obtained at different temperatures (293 K, 313 K and 333 K) for the adsorption of each dyestuff by poplar sawdust were applied to thermodynamical equations, and thermodynamical parameters (DeltaG, DeltaH and DeltaS) were also calculated. 相似文献
105.
Gaye Usluer Ilhan Ozgunes Hakan Leblebicioglu 《Annals of clinical microbiology and antimicrobials》2005,4(1):1-5
Background
Of the diverse presentation of neurobrucellosis, intra-medullary spinal cord abscess is extremely rare. Only four other cases have been reported so far. We present a case of spinal cord intra-medullary abscess due to Brucella melitensis.Case presentation
A forty-year-old female presented with progressive weakness of both lower limb with urinary incontinence of 6 months duration. She was febrile. Neurological examination revealed flaccid areflexic paraplegia with T10 below sensory impairment including perianal region. An intramedullary mass was diagnosed on Magnetic Resonance Image (MRI) scan extending from T12 to L2. At surgery, a large abscess was encountered at the conus medullaris, from which Brucella melitensis was grown on culture. She was started on streptomycin and doxycycline for 1 month, followed by rifampicin and doxycycline for 1 month. At 2-year follow-up, she had recovered only partially and continued to have impaired bladder function.Conclusion
Neurobrucellosis, if not treated early, can result in severe neurological morbidity and sequale, which may be irreversible. Hence it is important to consider the possibility of neurobrucellosis in endemic region and treat aggressively. 相似文献106.
Isbir T Yaylim I Arîkan S Küçücük S Camlíca H 《Molecular medicine (Cambridge, Mass.)》2002,8(9):521-524
BACKGROUND: Association between restriction fragment length polymorphisms (RFLP) of known oncogenes and a predisposition to develop cancer have been postulated. The L-myc gene is a potential molecular marker associated with cancer susceptibility as well as metastasis, prognosis, and adverse survival. Our aim was to test the hypothesis that there was an association between L-myc S allele in breast cancer and a predisposition to the disease. MATERIALS AND METHODS: The distribution of L-myc polymorphism in 56 patients with breast cancer was determined by polymerase chain reaction-based restriction fragment length polymorphism and compared with that of 51 healthy control subjects. RESULTS: The allele frequencies of L and S in breast cancer patients were 0.70 and 0.30, respectively and those in normal individuals were 0.54 and 0.46, respectively. This difference was primarily the result of a high frequency of the S allele among breast cancer patients compared to controls. The frequency of S allele was significantly higher in breast cancer patients than in normal individuals (p < 0.01). No correlation was observed between the presence of L-myc S allele and several parameters of each patient's history or characteristics of tumor. CONCLUSION: Our results suggested that L-myc polymorphism may be significant in an individual's susceptibility to breast cancer in Turkey and may be useful for identifying patients at high risk of developing breast cancer. 相似文献
107.
108.
A simple receptor modeling approach has been applied to groundwater pollution studies and has shown that maker trace elements
can be used effectively in source identification and apportionment. Groundwater and source materials from one coal-fired and
five oil-fired power plants, and one coal-tar deposit site have been analyzed by instrumental neutron activation analysis
for more than 20 minor and trace elements. In one of the oil-fired power plants, trace element patterns indicated a leak from
the hazardous waste surface impoundments owing to the failure of a hypolon liner. Also, the extent and spatial distribution
of groundwater contamination have been determined in a coal-tar deposit site. 相似文献
109.
110.
Oguzhan Tatar Necip Ilhan Nevin Ilhan Solmaz Susam Ibrahim Hanifi Ozercan 《Journal of biochemical and molecular toxicology》2019,33(9)
Breast cancer is the most common cancer among women in the world and the incidence is increasing alarmingly. It was aimed to determine the effect of raloxifene (RAL) and fluoxetine (FLX) on selected parameters in 7,12‐dimethylbenz(a)anthracene (DMBA)‐induced mammary carcinoma. Thirty‐two female Wistar albino rats were assorted into four groups: DMBA (group I), DMBA+RAL (group II), DMBA+FLX (group III), and DMBA+RAL+FLX (group IV). Mammary tissue vascular endothelial growth factor (VEGF), macrophage colony‐stimulating factor (M‐CSF), matrix metalloproteinase‐9 (MMP‐9), and tissue inhibitors of matrix metalloproteinase‐1 (TIMP‐1) levels were determined by the enzyme‐linked immunosorbent assay method. The tissue VEGF levels were lower in group IV compared with DMBA group. Decreased M‐CSF levels were observed in all therapeutic groups rather than the DMBA group, but the most effective decrease was found in group IV. Compared with the DMBA group, MMP‐9 levels were statistically significantly decreased in group II and group IV. However, TIMP‐1 levels were higher in the whole therapeutic groups rather than the DMBA group and the most effective increase was observed in group IV. Results of the present study suggest that combined therapy of RAL with FLX might lead to a better outcome targeting breast tumor. 相似文献