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   283篇
  免费   10篇
  2023年   4篇
  2022年   5篇
  2021年   8篇
  2020年   5篇
  2019年   2篇
  2018年   7篇
  2017年   8篇
  2016年   12篇
  2015年   8篇
  2014年   20篇
  2013年   27篇
  2012年   20篇
  2011年   25篇
  2010年   19篇
  2009年   11篇
  2008年   18篇
  2007年   21篇
  2006年   15篇
  2005年   15篇
  2004年   13篇
  2003年   7篇
  2002年   6篇
  2001年   5篇
  2000年   2篇
  1999年   2篇
  1998年   1篇
  1996年   2篇
  1995年   1篇
  1983年   1篇
  1980年   1篇
  1978年   1篇
  1959年   1篇
排序方式: 共有293条查询结果,搜索用时 15 毫秒
1.
The presence of time-dependent variations in the in vitro sensitivity of aorta preparations to either vasoconstricting or relaxing agents was investigated in rats maintained in light from 08: 00 to 20: 00 and in darkness from 20: 00 to 08: 00. Rat thoracic aorta rings were obtained from animals sacrificed at four different times of the day. The rat aorta was found to be more sensitive to the constricting effect of phenylephrine at 15: 00, and of 5-hydroxytryptamine at 21: 00. On the other hand, both endothelium-dependent and -independent relaxations were more remarkable at 03: 00 than at other times of the day. These variations represented significant circadian rhythms when analyzed by analysis of variance. Different in vitro responsiveness to these agents might reflect changes in the sensitivity and/or number of related receptors in vascular preparations. In conclusion, the circadian time of animal sacrifice to obtain vascular preparations constitutes an important aspect of the research method and a key determinant of findings. (Chronobiology International, 13(6), 465-475, 1996)  相似文献   
2.
Molecular Biology Reports - Neuronal senescence, triggered by telomere shortening, oncogene activation, DNA damage, or oxidative stress, has been associated with neurodegenerative diseases’...  相似文献   
3.
Functional & Integrative Genomics - Adenosine to inosine (A-to-I) editing in RNA is involved in various biological processes like gene expression, alternative splicing, and mRNA degradation...  相似文献   
4.
Molecular Biology Reports - The current study investigated the change in umbilical cord tissue and the number of markers of Wharton’s jelly mesenchymal stem cells (WJ-MSC) in pregnant women...  相似文献   
5.
Protein tyrosine kinases (PTKs) play an important role in T cell development and activation. In vitro and in vivo defects, resulting in variable deficiencies in thymic development and in T cell antigen receptor (TCR) signal transduction, in PTKs have been shown. ZAP70, one of those PTKs, is a 70-kDa tyrosine phosphoprotein and associates with the ζ chain and undergoes tyrosine phosphorylation following TCR stimulation. It is expressed in T and natural killer (NK) cells. Several mutations were shown to lead to an autosomal recessive form of severe combined immunodeficiency disease (SCID).  相似文献   
6.
We investigated the effects of AT-101/cisplatin combination treatment on the expression levels of apoptotic proteins and epigenetic events such as DNA methyltransferase (DNMT) and histone deacetylase (HDAC) enzyme activities in OVCAR-3 and MDAH-2774 ovarian cancer cells. XTT cell viability assay was used to evaluate cytotoxicity. For showing apoptosis, both DNA Fragmentation and caspase 3/7 activity measurements were performed. The expression levels of apoptotic proteins were assessed by human apoptosis antibody array. DNMT and HDAC activities were evaluated by ELISA assay and mRNA levels of DNMT1 and HDAC1 genes were quantified by qRT-PCR. Combination of AT-101/cisplatin resulted in strong synergistic cytotoxicity and apoptosis in human ovarian cancer cells. Combination treatment reduced some pivotal anti-apoptotic proteins such as Bcl-2, HIF-1A, cIAP-1, XIAP in OVCAR-3 cells, whereas p21, Bcl-2, cIAP-1, HSP27, Clusterin and XIAP in MDAH-2774 cells. Among the pro-apoptotic proteins, Bad, Bax, Fas, phospho-p53 (S46), Cleaved caspase-3, SMAC/Diablo, TNFR1 and Cytochrome c were induced in OVCAR-3 cells, whereas, Bax, TRAILR2, FADD, p27, phospho-p53 (S46), Cleaved caspase-3, Cytochrome c, SMAC/Diablo and TNFR1 were induced in MDAH-2774 cells. Combination treatment also inhibited both DNMT and HDAC activities and also mRNA levels in both ovarian cancer cells. AT-101 exhibits great potential in sensitization of human ovarian cancer cells to cisplatin treatment in vitro, suggesting that the combination of AT-101 with cisplatin may hold great promise for development as a novel chemotherapeutic approach to overcome platinum-resistance in human ovarian cancer.  相似文献   
7.
The present article is a taxonomic study of all spongy spumellarian radiolarian taxa with three and four coplanar spines or spongy arms occurring in the middle Carnian from the Köseyahya section, near the town of Elbistan, SE Turkey. This fauna is characteristic of the Tetraporobrachia haeckeli radiolarian Zone, and comes from an 8 m thick succession of clayey-cherty limestones occurring at the lower part of the section. In addition, a few species from the Middle and Upper Triassic from other areas have been also included in this study to improve some generic diagnoses, and to better comprehend the diversity and evolutionary trends of some genera, subfamilies and families. The taxonomy at the generic and suprageneric levels is based primarily on the types of microsphere. This new approach allowed new taxonomic arrangements of genera and suprageneric units, and suggested new phylogenetic relationships among these radiolarians and between them and younger radiolarians. The authors discuss and describe 69 species, of which 37 are new, and 14 genera, of which three are new (Paraparonaella, Pseudangulobracchia, and Ropanaella). The genus Triassoastrum and others are reinterpreted. All genera studied are assigned to five subfamilies, of which two are new (Tetrapaurinellinae and Triassocrucellinae), and two families (Tritrabidae and Veghicycliidae). Nine species in open nomenclature are also illustrated.  相似文献   
8.
In the present study the biofilm-forming characteristics of 99 serotyped (DMC strains) and 41 genus level-identified (IS strains) Salmonella strains originating from Turkey were investigated. The strains were selected based on their ability to show the biofilm morphotype on Congo red agar plates. In addition, all strains were evaluated with regard to properties related to forming pellicle structures, physical differences of pellicles, any changes in the media associated with the formation of pellicles, and the presence of cellulose within the formed biofilm matrix as determined using 366 nm UV light. The Salmonella Typhimurium DMC4 strain was the best producer of biofilm grown on polystyrene microtiter plates (optical density at 595 nm: 3.418). In subsequent experiments industrial process conditions were used to investigate different morphotyped Salmonella strains’ biofilm-forming capability on stainless steel, a commonly preferred surface for the food industries, and on polystyrene surfaces. The effect of other important industrial conditions, such as temperature (5, 20, 37°C), pH (4.5, 5.5, 6.5, 7.4) and NaCl concentration (0.5, 1.5, 5.5, 10.5%) on the production of biofilm of the different morphotyped Salmonella strains (DMC4; red, dry and rough morphotyped S. Typhimurium, DMC12; brown, dry and rough morphotyped S. Infantis, DMC13; pink, dry and rough morphotyped S. subsp. Roughform) were also assessed. On the other hand, pH values exhibited variable effects on biofilm-forming features for different Salmonella strains on both polystyrene and stainless steel surfaces.  相似文献   
9.
10.
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