全文获取类型
收费全文 | 119篇 |
免费 | 10篇 |
国内免费 | 2篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 7篇 |
2012年 | 7篇 |
2011年 | 11篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 6篇 |
2007年 | 7篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有131条查询结果,搜索用时 46 毫秒
61.
Mostafa M. S. Ismaiel Yassin M. El-Ayouty Peter C. Loewen Michele D. Piercey-Normore 《Journal of applied phycology》2014,26(4):1649-1658
Superoxide dismutase (SOD) is considered a primary antioxidant which defends against reactive oxygen species that are induced by environmental stress. In this study, we examined changes in SOD activity and expression in the cyanobacterium Spirulina (Arthrospira) platensis under iron and salinity stress; we characterized its induction under these stress conditions and we overexpressed the enzyme in a bacterial host for preliminary characterization. Analysis of SOD isoforms concludes that S. platensis was found to regulate only the iron-containing SOD isoform (FeSOD) in response to two types of stress that were tested. The FeSOD expression (on the level of both mRNA and enzyme activity) was induced by the stress conditions of salinity and iron levels. The FeSOD from S. platensis was overexpressed in Escherichia coli BL21. The recombinant FeSOD protein (about 23 kDa) was purified for characterization. It showed high specific activity and pH stability at 6.0–9.0, and it is relatively thermostable, retaining 45 % of its activity after 30 min at 90 °C. Phylogenetic analysis reveals that S. platensis FeSOD is grouped with the FeSODs from other cyanobacterial species and separated from those of the eukaryotic Chlorophyta, suggesting that the FeSOD gene may be used as a molecular marker in physiological, phylogenetic, and taxonomic studies. This study also suggests that the increased activity and expression of SOD may play a role in algal survival under stress conditions. 相似文献
62.
Ingrid M L?nnstedt Franco Caramia Jason Li Debora Fumagalli Roberto Salgado Andrew Rowan Max Salm Nnennaya Kanu Peter Savas Stuart Horswell Stephan Gade Sibylle Loibl Patrick Neven Christos Sotiriou Charles Swanton Sherene Loi Terence P Speed 《Genome biology》2014,15(9)
Intra-tumor heterogeneity concerns the existence of genetically different subclones within the same tumor. Single sample quantification of heterogeneity relies on precise determination of chromosomal copy numbers throughout the genome, and an assessment of whether identified mutation variant allele fractions match clonal or subclonal copy numbers. We discuss these issues using data from SNP arrays, whole exome sequencing and pathologist purity estimates on several breast cancers characterized by ERBB2 amplification. We show that chromosomal copy numbers can only be estimated from SNP array signals or sequencing depths for subclonal tumor samples with simple subclonal architectures under certain assumptions.
Electronic supplementary material
The online version of this article (doi:10.1186/s13059-014-0470-7) contains supplementary material, which is available to authorized users. 相似文献63.
Anmaar M. Abdul-Nabi Enas R. Yassin Nobish Varghese Hrishikesh Deshmukh Nabeel R. Yaseen 《PloS one》2010,5(8)
Different fusion oncogenes in acute myeloid leukemia (AML) have distinct clinical and laboratory features suggesting different modes of malignant transformation. Here we compare the in vitro effects of representatives of 4 major groups of AML fusion oncogenes on primary human CD34+ cells. As expected from their clinical similarities, MLL-AF9 and NUP98-HOXA9 had very similar effects in vitro. They both caused erythroid hyperplasia and a clear block in erythroid and myeloid maturation. On the other hand, AML1-ETO and PML-RARA had only modest effects on myeloid and erythroid differentiation. All oncogenes except PML-RARA caused a dramatic increase in long-term proliferation and self-renewal. Gene expression profiling revealed two distinct temporal patterns of gene deregulation. Gene deregulation by MLL-AF9 and NUP98-HOXA9 peaked 3 days after transduction. In contrast, the vast majority of gene deregulation by AML1-ETO and PML-RARA occurred within 6 hours, followed by a dramatic drop in the numbers of deregulated genes. Interestingly, the p53 inhibitor MDM2 was upregulated by AML1-ETO at 6 hours. Nutlin-3, an inhibitor of the interaction between MDM2 and p53, specifically inhibited the proliferation and self-renewal of primary human CD34+ cells transduced with AML1-ETO, suggesting that MDM2 upregulation plays a role in cell transformation by AML1-ETO. These data show that differences among AML fusion oncogenes can be recapitulated in vitro using primary human CD34+ cells and that early gene expression profiling in these cells can reveal potential drug targets in AML. 相似文献
64.
Luis Eduardo Cuevas Mohammed Ahmed Yassin Najla Al-Sonboli Lovett Lawson Isabel Arbide Nasher Al-Aghbari Jeevan Bahadur Sherchand Amin Al-Absi Emmanuel Nnamdi Emenyonu Yared Merid Mosis Ifenyi Okobi Juliana Olubunmi Onuoha Melkamsew Aschalew Abraham Aseffa Greg Harper Rachel Mary Anderson de Cuevas Kristin Kremer Dick van Soolingen Carl-Michael Nathanson Jean Joly Brian Faragher Stephen Bertel Squire Andrew Ramsay 《PLoS medicine》2011,8(7)
Background
More than 50 million people around the world are investigated for tuberculosis using sputum smear microscopy annually. This process requires repeated visits and patients often drop out.Methods and Findings
This clinical trial of adults with cough ≥2 wk duration (in Ethiopia, Nepal, Nigeria, and Yemen) compared the sensitivity/specificity of two sputum samples collected “on the spot” during the first visit plus one sputum sample collected the following morning (spot-spot-morning [SSM]) versus the standard spot-morning-spot (SMS) scheme. Analyses were per protocol analysis (PPA) and intention to treat (ITT). A sub-analysis compared just the first two smears of each scheme, spot-spot and spot-morning.In total, 6,627 patients (3,052 SSM/3,575 SMS) were enrolled; 6,466 had culture and 1,526 were culture-positive. The sensitivity of SSM (ITT, 70.2%, 95% CI 66.5%–73.9%) was non-inferior to the sensitivity of SMS (PPA, 65.9%, 95% CI 62.3%–69.5%). Similarly, the specificity of SSM (ITT, 96.9%, 95% CI 93.2%–99.9%) was non-inferior to the specificity of SMS (ITT, 97.6%, 95% CI 94.0%–99.9%). The sensitivity of spot-spot (ITT, 63.6%, 95% CI 59.7%–67.5%) was also non-inferior to spot-morning (ITT, 64.8%, 95% CI 61.3%–68.3%), as the difference was within the selected −5% non-inferiority limit (difference ITT = 1.4%, 95% CI −3.7% to 6.6%). Patients screened using the SSM scheme were more likely to provide the first two specimens than patients screened with the SMS scheme (98% versus 94.2%, p<0.01). The PPA and ITT analysis resulted in similar results.Conclusions
The sensitivity and specificity of SSM are non-inferior to those of SMS, with a higher proportion of patients submitting specimens. The scheme identifies most smear-positive patients on the first day of consultation.Trial Registration
Current Controlled Trials ISRCTN53339491 Please see later in the article for the Editors'' Summary 相似文献65.
Yassin MA Petrucci R Garie KT Harper G Arbide I Aschalew M Merid Y Kebede Z Bawazir AA Abuamer NM Cuevas LE 《PloS one》2011,6(9):e23733
Background
Diagnosis of childhood tuberculosis (TB) is difficult in high TB burden settings. Interferon-gamma-induced protein 10 (IP10) has been suggested as a marker of TB infection and disease, but its ability to differentiate the two conditions remains uncertain.Objectives
To describe Interferon-gamma (INFγ) and IP10 expression in children with TB infection and disease and controls to assess their potential to differentiate latent and active TB.Methods
This was a cross sectional study of 322 1–15 years old children with symptoms of TB (28 confirmed, 136 probable and 131 unlikely TB), 335 children in contact with adults with pulmonary TB and 156 community controls in Southern Ethiopia. The Tuberculin Skin Test (TST) and Quantiferon-In-Tube (QFT-IT) were performed. INFγ and IP10 were measured in plasma supernatants.Results and Interpretation
Children with confirmed and probable TB and contacts were more likely to have TST+ (78.6%, 59.3% and 54.1%, respectively) than children with unlikely TB (28.7%) and controls (12.8%) (p<0.001). Children with confirmed TB (59.3%) and contacts (44.7%) were more likely to have INFγ+ than children with probable (37.6%) or unlikely TB (28.1%) and controls (13.1%) (p<0.001). IP10 concentrations were higher in INFγ+ children independently of TST (p<0.001). There was no difference between IP10 concentrations of children with confirmed TB and contacts (p = 0.8) and children with and without HIV (p>0.1).INFγ and IP10 can identify children with TB infection and disease, but cannot differentiate between the two conditions. HIV status did not affect the expression of IP10. 相似文献66.
M Aravena-Román C Spröer C Siering T Inglis P Schumann AF Yassin 《Systematic and applied microbiology》2012,35(6):380-384
An unknown lipophilic coryneform bacterium isolated from the blood cultures of a patient with bacteremia was characterized by phenotypic and molecular genetic methods. Chemical analysis revealed the presence of short chain mycolic acids consistent with the genus Corynebacterium. The DNA G+C content was 60.8mol%. Comparative 16S rRNA gene sequence analysis demonstrated that the isolate represents a new subline within the genus Corynebacterium. The closely phylogenetic relative of the unknown bacterium was found to be C. tuscaniense (97.8% sequence similarity). Partial rpoB gene sequence revealed that strain IMMIB L-2475(T) exhibited 13.5% sequence divergence with C. tuscaniense. The unknown bacterium was distinguished from C. tuscaniense by, DNA-DNA hybridization, cellular fatty acid profiles, MALDI-TOF analyses of cell extracts and biochemical tests. Based on the phylogenetic and phenotypic criteria, it is proposed that this bacterium be classified as new species, Corynebacterium aquatimens sp. nov., and is represented by strain IMMIB L-2475(T) (=DSM 45632(T)=CCUG 61574(T)). 相似文献
67.
Amir Yassin Nelly Gidaszewski Béatrice Albert Jean Hivert Jean R. David Virginie Orgogozo Vincent Debat 《Fly》2012,6(4):298-302
Thirteen drosophilid species belonging to seven genera and two subfamilies are reported from three coral islands (namely Europa, Juan de Nova and Glorioso) that belong to the Scattered Islands in the Indian Ocean. Five species are cosmopolitan and five are African. Three are endemic to the insular Western Indian Ocean, including a presumably new Scaptodrosophila species. On the island of Juan de Nova, most captured flies had pollinia attached to the bases of their proboscis. DNA analysis using the rbcl gene revealed that these pollinia belong to the genus Leptadenia (Apocynaceae), of which a single species L. madagascariensis, endemic in Madagascar and Comoros, is present in this island. This is the first reported association between this plant and drosophilids. 相似文献
68.
Nawar Shara Sayf A. Yassin Eduardas Valaitis Hong Wang Barbara V. Howard Wenyu Wang Elisa T. Lee Jason G. Umans 《PloS one》2015,10(9)
Kidney and cardiovascular disease are widespread among populations with high prevalence of diabetes, such as American Indians participating in the Strong Heart Study (SHS). Studying these conditions simultaneously in longitudinal studies is challenging, because the morbidity and mortality associated with these diseases result in missing data, and these data are likely not missing at random. When such data are merely excluded, study findings may be compromised. In this article, a subset of 2264 participants with complete renal function data from Strong Heart Exams 1 (1989–1991), 2 (1993–1995), and 3 (1998–1999) was used to examine the performance of five methods used to impute missing data: listwise deletion, mean of serial measures, adjacent value, multiple imputation, and pattern-mixture. Three missing at random models and one non-missing at random model were used to compare the performance of the imputation techniques on randomly and non-randomly missing data. The pattern-mixture method was found to perform best for imputing renal function data that were not missing at random. Determining whether data are missing at random or not can help in choosing the imputation method that will provide the most accurate results. 相似文献
69.
70.
Sherene Loi Christos Sotiriou Benjamin Haibe-Kains Francoise Lallemand Nelly M Conus Martine J Piccart Terence P Speed Grant A McArthur 《BMC medical genomics》2009,2(1):1-9