全文获取类型
收费全文 | 3265篇 |
免费 | 269篇 |
国内免费 | 2篇 |
出版年
2023年 | 17篇 |
2022年 | 13篇 |
2021年 | 53篇 |
2020年 | 38篇 |
2019年 | 41篇 |
2018年 | 51篇 |
2017年 | 48篇 |
2016年 | 87篇 |
2015年 | 146篇 |
2014年 | 163篇 |
2013年 | 217篇 |
2012年 | 248篇 |
2011年 | 264篇 |
2010年 | 182篇 |
2009年 | 177篇 |
2008年 | 242篇 |
2007年 | 232篇 |
2006年 | 200篇 |
2005年 | 199篇 |
2004年 | 205篇 |
2003年 | 167篇 |
2002年 | 178篇 |
2001年 | 53篇 |
2000年 | 31篇 |
1999年 | 33篇 |
1998年 | 33篇 |
1997年 | 26篇 |
1996年 | 17篇 |
1995年 | 23篇 |
1994年 | 11篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 9篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1973年 | 3篇 |
1935年 | 1篇 |
排序方式: 共有3536条查询结果,搜索用时 31 毫秒
11.
Lucia Romani Josefa Koroivueta Andrew C. Steer Mike Kama John M. Kaldor Handan Wand Mohammed Hamid Margot J. Whitfeld 《PLoS neglected tropical diseases》2015,9(3)
BackgroundScabies is recognised as a major public health problem in many countries, and is responsible for significant morbidity due to secondary bacterial infection of the skin causing impetigo, abscesses and cellulitis, that can in turn lead to serious systemic complications such as septicaemia, kidney disease and, potentially, rheumatic heart disease. Despite the apparent burden of disease in many countries, there have been few large-scale surveys of scabies prevalence or risk factors. We undertook a population-based survey in Fiji of scabies and impetigo to evaluate the magnitude of the problem and inform public health strategies.ConclusionsAs far as we are aware, this is the first national survey of scabies and impetigo ever conducted. We found that scabies occurs at high levels across all age groups, ethnicities, and geographical locations. Improved strategies are urgently needed to achieve control of scabies and its complications in endemic communities. 相似文献
12.
13.
Modulations in lipid A and phospholipid biosynthesis pathways influence outer membrane protein assembly in Escherichia coli K-12 总被引:3,自引:3,他引:0
The assembly defect of a mutant outer membrane protein, OmpF315, can be corrected by suppressor mutations that lower lipopolysaccharide (LPS) levels and indirectly elevate phospholipid levels. One such assembly suppressor mutation, asmB1 , is an allele of lpxC ( envA ) whose product catalyses the first rate-limiting step in the lipid A (LPS) biosynthesis pathway. Besides reducing LPS levels, asmB1 confers sensitivity to MacConkey medium. A mutation, sabA1 , that reverses the MacConkey sensitivity phenotype of asmB1 maps within fabZ (whose product is needed for phospholipid synthesis from a precursor) is also required for lipid A synthesis. In addition to reversing MacConkey sensitivity, the sabA1 mutation reverses the OmpF315 assembly suppression phenotype of asmB1 . These results show that OmpF315 assembly suppression by asmB1 , which is achieved by lowering LPS levels, can be averted by a subsequent aberration in phospholipid synthesis at a point where the biosynthetic pathways for these two lipid molecules split. OmpF315 assembly suppression can also be achieved in an asmB + background where FabZ expression is increased. The data obtained in this study provide genetic evidence that elevated phospholipid levels and/or phospholipid to LPS ratios are necessary for assembly suppression. 相似文献
14.
15.
16.
17.
Saida Abdelli Klearchos K. Papas Kate R. Mueller Mike P. Murtaugh Bernhard J. Hering Christophe Bonny 《PloS one》2014,9(7)
Stress conditions generated throughout pancreatic islet processing initiate the activation of pro-inflammatory pathways and beta-cell destruction. Our goal is to identify relevant and preferably beta-specific markers to assess the activation of beta-cell stress and apoptotic mechanisms, and therefore the general quality of the islet preparation prior to transplantation. Protein expression and activation were analyzed by Western blotting and kinase assays. ATP measurements were performed by a luminescence-based assay. Oxygen consumption rate (OCR) was measured based on standard protocols using fiber optic sensors. Total RNA was used for gene expression analyzes. Our results indicate that pancreas digestion initiates a potent stress response in the islets by activating two stress kinases, c-Jun N-terminal Kinase (JNK) and p38. JNK1 protein levels remained unchanged between different islet preparations and following culture. In contrast, levels of JNK3 increased after islet culture, but varied markedly, with a subset of preparations bearing low JNK3 expression. The observed changes in JNK3 protein content strongly correlated with OCR measurements as determined by the Spearman''s rank correlation coefficient rho
in the matching islet samples, while inversely correlating with c-fos mRNA expression . In conclusion, pancreas digestion recruits JNK and p38 kinases that are known to participate to beta-cell apoptosis. Concomitantly, the islet isolation alters JNK3 and c-fos expression, both strongly correlating with OCR. Thus, a comparative analysis of JNK3 and c-fos expression before and after culture may provide for novel markers to assess islet quality prior to transplantation. JNK3 has the advantage over all other proposed markers to be islet-specific, and thus to provide for a marker independent of non-beta cell contamination. 相似文献
18.
Correlation of surface sediment diatoms with the present lake water pH in 28 Algoma lakes,Ontario, Canada 总被引:1,自引:1,他引:0
The surface sediment diatom analysis of 28 Algoma lakes (pH 4.40–8.13) indicates that even though each lake has a widely different aquatic environment and characteristic diatom assemblage, a definite relationship exists between the lake water pH and their diatom assemblages. In the acidic lakes acidobiontic and acidophilous diatom species predominate whereas in circumneutral and alkaline lakes circumneutral and alkaliphilous diatoms were most common. Cluster analysis of the pH indicator diatom assemblages grouped the study lakes into three distinct cluster groups. These groups also closely corresponded to lake water pH. On the basis of published ecological information as well as their presence in our study lakes, the pH indicator status of a number of diatom taxa have been discussed. A detailed listing of the diatom taxa identified and their pH indicator status is provided in order to facilitate their use in future diatom-inferred pH studies. 相似文献
19.
20.
Community perspectives on scabies,impetigo and mass drug administration in Fiji: A qualitative study
Elke Mitchell Stephen Bell Li Jun Thean Aalisha Sahukhan Mike Kama Aminiasi Koroivueti John Kaldor Andrew Steer Lucia Romani 《PLoS neglected tropical diseases》2020,14(12)
Scabies is endemic in Fiji and is a significant cause of morbidity. Little is known about the sociocultural beliefs and practices that affect the occurrence of scabies and impetigo, or community attitudes towards the strategy of mass drug administration that is emerging as a public health option for scabies and impetigo control in Fiji and other countries. Data were collected during semi-structured interviews with 33 community members in four locations in Fiji’s Northern Division. Thematic analysis examined participants’ lived experiences of scabies and impetigo; community knowledge and perceptions about scabies and impetigo aetiology and transmission; community-based treatment and prevention measures; and attitudes towards mass drug administration. Many indigenous Fijian (iTaukei) participants noted extensive and ongoing experience of scabies and impetigo among children in their families and communities, but only one participant of Indian descent (Indo-Fijian) identified personal childhood experience of scabies. Scabies and impetigo were perceived as diseases affecting children, impacting on school attendance and families’ quality of sleep. Awareness of scabies and impetigo was considerable, but there were major misconceptions around disease causation and transmission. Traditional remedies were preferred for scabies treatment, followed by biomedicines provided by local health centres and hospitals. Treatment of close household contacts was not prioritised. Attitudes towards mass drug administration to control scabies were mostly positive, although some concerns were noted about adverse effects and hesitation to participate in the planned scabies elimination programme. Findings from this first study to document perspectives and experiences related to scabies and impetigo and their management in the Asia Pacific region illustrate that a community-centred approach to scabies and impetigo is needed for the success of control efforts in Fiji, and most likely in other affected countries. This includes community-based health promotion messaging on the social dynamics of scabies transmission, and a campaign of education and community engagement prior to mass drug administration. 相似文献