首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   235篇
  免费   8篇
  2022年   3篇
  2021年   11篇
  2020年   3篇
  2019年   9篇
  2018年   8篇
  2017年   12篇
  2016年   11篇
  2015年   4篇
  2014年   12篇
  2013年   13篇
  2012年   24篇
  2011年   18篇
  2010年   12篇
  2009年   7篇
  2008年   15篇
  2007年   13篇
  2006年   14篇
  2005年   21篇
  2004年   9篇
  2003年   6篇
  2002年   8篇
  2001年   4篇
  2000年   5篇
  1989年   1篇
排序方式: 共有243条查询结果,搜索用时 15 毫秒
1.
2.
ABSTRACT

Circadian disruption has been linked with immune-related morbidities including autoimmune diseases. PERIOD3 (PER3) clock gene is a key player in the mammalian circadian system. This study evaluated the possible association of PER3 rs2797685 (G/A) polymorphism and susceptibility of autoimmune thyroid diseases (AITD) and assessed if this SNP contributes to disease characteristics and serum levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The PER3 rs2797685 (G/A) polymorphism was assessed in 125 patients with AITD [Graves’ disease (GD), 69; Hashimoto’s thyroiditis (HT), 56] and 115 unrelated healthy controls. Subjects carrying at least one variant allele of PER3 rs2797685 (GA+AA) had increased risk for GD (OR 1.9, 95% CI 1–3.61, p= .05). There were no differences in the frequencies of genotypes and alleles of the PER3 rs2797685 polymorphism between HT patients and control subjects. No association was observed between genotypes of the studied SNP and any of the disease characteristics in GD and HT patients. The GA+AA genotype of PER3 rs2797685 was associated with lower levels of IL-6 in patients with Graves’ disease. There were no differences between genotypes of the studied SNP regarding TNF-α levels in GD, HT or control groups. In conclusion, this study provides the first evidence for a genetic association between GD and the PER3 gene, highlighting the possible relevance of polymorphisms in clock genes in the etiopathogenesis of AITD. However, functional studies to identify the underlying molecular mechanisms of this association are needed to translate these findings to clinical applications.  相似文献   
3.

Background

A decline in hospitalizations and pain episodes among those with sickle cell disease (SCD) who take hydroxyurea (HU) has been shown when compared to pre-HU patterns but paradoxically, when compared to those who have never been treated, HU recipients often have more frequent hospitalizations. This analysis evaluates the impact of increasing usage of HU on trends in hospitalizations and blood transfusions within a large SCD treatment program.

Methods

Eligibility was restricted to patients with Hb SS or Hb Sβ0-thalassemia who were 2–18 years old between 2006–2010 and received care at St. Jude Children''s Research Hospital (N = 508). Hospitalizations and blood transfusions were calculated for each of the years under study for those exposed and never exposed to HU. Differences in number of hospitalizations before and after HU initiation were compared.

Results

The proportion of patients receiving HU increased by 4% per year on average. In the HU exposed group, a modest decline in mean per-patient hospitalizations and per-patient hospital days occurred, while those never exposed to HU trended toward a slight increase over time. Rates of blood transfusions declined among those on HU but not in patients never exposed to HU. Patients on HU had a median of one fewer hospital admission in the year after initiation of HU, compared to the year prior. Two deaths occurred in the patient population, both of whom were not exposed to HU.

Conclusions

Increasing usage of HU was concurrent with decreased hospitalization rates and blood transfusions. Our results support the utility of HU on decreasing hospitalizations and transfusions for patients with SCD outside of the clinical trial setting.  相似文献   
4.
5.

Cysteine (Cys) is the first identified molecule in plant metabolism which includes both sulfur and nitrogen. It can be synthesized in three cellular compartments, containing chloroplast, cytoplasm and mitochondrion. The final step of cysteine biosynthesis is catalyzed by the O-acetylserine(thiol)lyase enzyme (OASTL, E.C. 4.2.99). In the present study, seven members of the OASTL gene family in the sorghum (Sorghum bicolor) genome were identified at a genome-wide scale and comparative bioinformatics analyses were performed between sorghum and Arabidopsis OASTLs. In all OASTL proteins, a pyridoxal-phosphate dependent domain structure (PALP, PF00291) was identified. The gene ontology annotations also revealed that all sorghum OASTL genes have KOG1252 (Cystathionine beta-synthase and related enzyme) and K01738 (cysteine synthase A) activities. In promotor sequences of OASTL genes, diverse cis-acting elements were found, including hormone and light responsiveness, abiotic stress responsiveness, and tissue-specific ones (meristem and endosperm). Sorghum OASTL genes demonstrated medium or high level expressions in anatomical parts and developmental stages based on the digital expression data. Expression of OASTL genes were also analyzed under cadmium (Cd) stress in sorghum by Real Time-quantitative PCR (RT-qPCR). The results exclusively showed that OASTL A1-2 gene was 1.12 fold up-regulated in roots, whereas cysteine synthase 26 was 2.25 fold down-regulated in leaves. The predicted 3D structure of OASTLs indicated some structural diversities as well as variations in the secondary structures.

  相似文献   
6.
The effects of 24-epibrassinolide (24-epiBL) on seedling growth, antioxidative system, lipid peroxidation, proline and soluble protein content were investigated in seedlings of the salt-sensitive rice cultivar IR-28. Seedling growth of rice plants was improved by 24-epiBL treatment under salt stress conditions. When seedlings treated with 24-epiBL were subjected to 120 mM NaCl stress, the activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6) and glutathione reductase (EC 1.6.4.2) did not show significant difference, whereas the activity of ascorbate peroxidase (EC 1.11.1.11) significantly increased. Increased activity of peroxidase (EC 1.11.1.7) under NaCl stress showed remarkable decrease in the 24-epiBL+NaCl-applied group. Lipid peroxidation level significantly increased under salt stress but decreased with 24-epiBL application revealing that less oxidative damage occurred in this group (24-epiBL+NaCl). In addition, increased proline content in the NaCl-applied group was decreased by 24-epiBL application in the 24-epiBL+NaCl-applied group. Soluble protein content was increased by 24-epiBL application even under NaCl stress, being also higher than control conditions (no 24-epiBL or NaCl treatment). 24-epiBL treatment considerably alleviated oxidative damage that occurred under NaCl-stressed conditions and improved seedling growth in part under salt stress in sensitive IR-28 seedlings.  相似文献   
7.
The purpose of this study was to describe certain morphological characteristics of women soccer players and to examine aspects of training and performance. Twenty-two anthropometric sites were used in measurements of somatotype and body composition; flexibility, agility, anaerobic power, leg muscle power, and dynamic pulmonary functions were used as performance variables. Measurements were made on 17 professional athletes and 17 age-matched sedentary women who acted as controls. The women soccer players showed less fat content and less lean body mass than did the sedentary women. The mean somatotype for the soccer players was 3.07-3.55-2.43 and for the nonathletes was 3.57-3.35-2.90. Anaerobic power, leg muscle power, and agility in the athletes were higher than in the nonathletes, whereas no differences were found in flexibility and pulmonary functions (p > 0.05). The women soccer players showed more significantly mesomorphic, less endomorphic, least ectomorphic components and higher performance level than did the sedentary women.  相似文献   
8.
9.
The objective of this study was to investigate oxidative DNA damage, and the levels of antioxidant enzymes (AOE) and selenium (Se) in relation to iodine deficiency and/or goiter in children. The study was performed in a group of goitrous high school children (15-18 years of age) ( n =14) with severe or moderate iodine deficiency. Thyroid hormones (TSH, FT 4 , TT 4 , FT 3 , TT 3 ), urinary iodine (UI) and plasma Se levels, and erythrocyte glutathione peroxidase (GSHPx), superoxide dismutase (SOD) and catalase (CAT) activities were determined and compared with those of a control group consisting of non-goitrous high school children ( n =14) with normal UI levels or mild iodine deficiency. In the goitrous group, concentrations of FT 4 , TT 4 , plasma Se and UI, and activities of GSHPx and SOD were found to be significantly lower. Six typical hydroxyl radical-induced base lesions in genomic DNA of peripheral blood were identified and quantified by gas chromatography/isotope-dilution mass spectrometry (GC/IDMS), and higher levels of DNA base lesions were observed in the goitrous group. The results suggest that highly iodine-deficient goitrous children may be under oxidative stress, which may lead to greater level of oxidative damage to DNA. This study supports the evidence for the reported relationship between iodine deficiency and the increased incidence of thyroid malignancies.  相似文献   
10.
Axl receptor tyrosine kinase is implicated in several malignancies and is the receptor for the vitamin K-dependent growth factor Gas6. From a yeast two-hybrid screen of protein-protein interactions with the Axl cytoplasmic domain, we detected a previously uncharacterised SH2 domain-containing protein. We cloned two novel splice variants of this protein that give rise to 1409- and 1419-amino acid proteins, differing only in their N-terminal residues and yielding a 150-kDa protein product by in vitro translation. The Axl-interacting C-terminus contains a tandem SH2 and PTB domain combination homologous to the focal adhesion protein tensin. We detected interaction of Axl with both domains in mammalian cells by co-immunoprecipitation and two-hybrid analyses. In addition, the protein possesses an N-terminal putative phorbol ester-binding C1 domain as well as a central tyrosine phosphatase motif. Thus, we have named the protein C1 domain-containing phosphatase and TENsin homologue (C1-TEN). Northern blot analysis of C1-TEN in human tissues revealed highest expression in heart, kidney, and liver. In summary, we have identified a novel multi-domain intracellular protein that interacts with Axl and which may furthermore be involved in other signal transduction pathways.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号