全文获取类型
收费全文 | 99篇 |
免费 | 6篇 |
出版年
2021年 | 1篇 |
2020年 | 3篇 |
2018年 | 1篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 13篇 |
2013年 | 6篇 |
2012年 | 7篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 7篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有105条查询结果,搜索用时 15 毫秒
11.
Stephan P. Frankenfeld Leonardo P. Oliveira Victor H. Ortenzi Igor CC. Rego-Monteiro Elen A. Chaves Andrea C. Ferreira Alvaro C. Leit?o Denise P. Carvalho Rodrigo S. Fortunato 《PloS one》2014,9(9)
The abuse of anabolic androgenic steroids (AAS) may cause side effects in several tissues. Oxidative stress is linked to the pathophysiology of most of these alterations, being involved in fibrosis, cellular proliferation, tumorigenesis, amongst others. Thus, the aim of this study was to determine the impact of supraphysiological doses of nandrolone decanoate (DECA) on the redox balance of liver, heart and kidney. Wistar male rats were treated with intramuscular injections of vehicle or DECA (1 mg.100 g−1 body weight) once a week for 8 weeks. The activity and mRNA levels of NADPH Oxidase (NOX), and the activity of catalase, glutathione peroxidase (GPx) and total superoxide dismutase (SOD), as well as the reduced thiol and carbonyl residue proteins, were measured in liver, heart and kidney. DECA treatment increased NOX activity in heart and liver, but NOX2 mRNA levels were only increased in heart. Liver catalase and SOD activities were decreased in the DECA-treated group, but only catalase activity was decreased in the kidney. No differences were detected in GPx activity. Thiol residues were decreased in the liver and kidney of treated animals in comparison to the control group, while carbonyl residues were increased in the kidney after the treatment. Taken together, our results show that chronically administered DECA is able to disrupt the cellular redox balance, leading to an oxidative stress state. 相似文献
12.
Remi Tachet Paolo Santi Stanislav Sobolevsky Luis Ignacio Reyes-Castro Emilio Frazzoli Dirk Helbing Carlo Ratti 《PloS one》2016,11(3)
Since their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs). Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities. 相似文献
13.
14.
15.
Michael CW Chan Renee WY Chan Wendy CL Yu Carol CC Ho WH Chui CK Lo Kit M Yuen Yi Guan John M Nicholls JS Malik Peiris 《Respiratory research》2009,10(1):102
Background
Highly pathogenic avian influenza (HPAI) H5N1 virus is entrenched in poultry in Asia and Africa and continues to infect humans zoonotically causing acute respiratory disease syndrome and death. There is evidence that the virus may sometimes spread beyond respiratory tract to cause disseminated infection. The primary target cell for HPAI H5N1 virus in human lung is the alveolar epithelial cell. Alveolar epithelium and its adjacent lung microvascular endothelium form host barriers to the initiation of infection and dissemination of influenza H5N1 infection in humans. These are polarized cells and the polarity of influenza virus entry and egress as well as the secretion of cytokines and chemokines from the virus infected cells are likely to be central to the pathogenesis of human H5N1 disease.Aim
To study influenza A (H5N1) virus replication and host innate immune responses in polarized primary human alveolar epithelial cells and lung microvascular endothelial cells and its relevance to the pathogenesis of human H5N1 disease.Methods
We use an in vitro model of polarized primary human alveolar epithelial cells and lung microvascular endothelial cells grown in transwell culture inserts to compare infection with influenza A subtype H1N1 and H5N1 viruses via the apical or basolateral surfaces.Results
We demonstrate that both influenza H1N1 and H5N1 viruses efficiently infect alveolar epithelial cells from both apical and basolateral surface of the epithelium but release of newly formed virus is mainly from the apical side of the epithelium. In contrast, influenza H5N1 virus, but not H1N1 virus, efficiently infected polarized microvascular endothelial cells from both apical and basolateral aspects. This provides a mechanistic explanation for how H5N1 virus may infect the lung from systemic circulation. Epidemiological evidence has implicated ingestion of virus-contaminated foods as the source of infection in some instances and our data suggests that viremia, secondary to, for example, gastro-intestinal infection, can potentially lead to infection of the lung. HPAI H5N1 virus was a more potent inducer of cytokines (e.g. IP-10, RANTES, IL-6) in comparison to H1N1 virus in alveolar epithelial cells, and these virus-induced chemokines were secreted onto both the apical and basolateral aspects of the polarized alveolar epithelium.Conclusion
The predilection of viruses for different routes of entry and egress from the infected cell is important in understanding the pathogenesis of influenza H5N1 infection and may help unravel the pathogenesis of human H5N1 disease. 相似文献16.
Human crowd motion is mainly driven by self-organized processes based on local interactions among pedestrians. While most studies of crowd behaviour consider only interactions among isolated individuals, it turns out that up to 70% of people in a crowd are actually moving in groups, such as friends, couples, or families walking together. These groups constitute medium-scale aggregated structures and their impact on crowd dynamics is still largely unknown. In this work, we analyze the motion of approximately 1500 pedestrian groups under natural condition, and show that social interactions among group members generate typical group walking patterns that influence crowd dynamics. At low density, group members tend to walk side by side, forming a line perpendicular to the walking direction. As the density increases, however, the linear walking formation is bent forward, turning it into a V-like pattern. These spatial patterns can be well described by a model based on social communication between group members. We show that the V-like walking pattern facilitates social interactions within the group, but reduces the flow because of its “non-aerodynamic” shape. Therefore, when crowd density increases, the group organization results from a trade-off between walking faster and facilitating social exchange. These insights demonstrate that crowd dynamics is not only determined by physical constraints induced by other pedestrians and the environment, but also significantly by communicative, social interactions among individuals. 相似文献
17.
Tainá CC Monte Rosana Gentile Juberlan Garcia Ester Mota Jeannie N Santos Arnaldo Maldonado Júnior 《Memórias do Instituto Oswaldo Cruz》2014,109(8):1057-1063
Angiostrongylus cantonensis is the etiologic agent of eosinophilic
meningoencephalitis in humans. Cases have been recorded in many parts of the world,
including Brazil. The aim of this study was to compare the differences in the biology
and morphology of two different Brazilian haplotypes of A. : ac8 and
ac9. A significantly larger number of L1 larvae eliminated in the faeces of rodents
at the beginning of the patent period was observed for ac9 haplotype and compared to
the total of L1 larvae eliminated, there was a significant difference between the two
haplotypes. The ac9 haplotype showed a significant difference in the proportion of
female and male specimens (0.6:1), but the same was not observed for ac8 (1.2:1). The
morphometric analysis showed that male and female specimens isolated from ac8
haplotype were significantly larger with respect to body length, oesophagus length,
spicule length (male) and distance from the anus to the rear end (female) compared to
specimens from ac9. The morphological analysis by light microscopy showed little
variation in the level of bifurcations at the lateral rays in the right lobe of the
copulatory bursa between the two haplotypes. The biological, morphological and
morphometric variations observed between the two haplotypes agree with the observed
variation at the molecular level using the cytochrome oxidase subunit I marker and
reinforce the possible influence of geographical isolation on the development of
these haplotypes. 相似文献
18.
Periconceptional parental conditions and perimembranous ventricular septal defects in the offspring
下载免费PDF全文
![点击此处可从《Birth defects research. Part A, Clinical and molecular teratology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kim P.J. Wijnands Gerda A. Zeilmaker Willemijn M. Meijer Willem A. Helbing Régine P.M. Steegers‐Theunissen 《Birth defects research. Part A, Clinical and molecular teratology》2014,100(12):944-950
Background: The perimembranous ventricular septal (pVSD) defect is the most common congenital heart disease phenotype. Several parental factors are associated with pVSD risk in the offspring. To contribute to the future prevention of pVSDs, we investigated associations with nongenetic parental conditions. Methods: In a case–control study with standardized data collection at 17 months after birth, 115 parents of a child with pVSD and 484 parents of a healthy child completed questionnaires about periconceptional nongenetic conditions. Univariable and multivariable logistic regression analyses were used to estimate odds ratios (OR) with 95% confidence intervals (95% CI). Results: Complete data were available for 588 families (98%). Maternal risk conditions associated with pVSD offspring were a positive family history of congenital heart disease (OR, 2.61; 95%CI, 0.98–6.91), medication use (OR, 1.80; 95%CI, 1.13–2.85) and advanced age (OR, 1.07; 95%CI, 1.02–1.12). Exposure to phthalates (OR, 1.93; 95%CI, 1.05–3.54) was the only paternal risk condition associated with pVSD offspring. Conclusion: Four periconceptional parental conditions contributed to pVSD risk in the offspring. Couples planning pregnancy should be counseled on these risk conditions which are partially modifiable to contribute to the future prevention of pVSDs. Birth Defects Research (Part A) 100:944–950, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
19.
20.
Claudia T Guimaraes Christiano C Simoes Maria Marta Pastina Lyza G Maron Jurandir V Magalhaes Renato CC Vasconcellos Lauro JM Guimaraes Ubiraci GP Lana Carlos FS Tinoco Roberto W Noda Silvia N Jardim-Belicuas Leon V Kochian Vera MC Alves Sidney N Parentoni 《BMC genomics》2014,15(1)