全文获取类型
收费全文 | 193篇 |
免费 | 18篇 |
专业分类
211篇 |
出版年
2024年 | 1篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 11篇 |
2015年 | 12篇 |
2014年 | 14篇 |
2013年 | 19篇 |
2012年 | 17篇 |
2011年 | 24篇 |
2010年 | 11篇 |
2009年 | 7篇 |
2008年 | 12篇 |
2007年 | 9篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1996年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有211条查询结果,搜索用时 0 毫秒
71.
Perrine Marcenac W. Robert Shaw Evdoxia G. Kakani Sara N. Mitchell Adam South Kristine Werling Eryney Marrogi Daniel G. Abernathy Rakiswend Serge Yerbanga Roch K. Dabir Abdoulaye Diabat Thierry Lefvre Flaminia Catteruccia 《PLoS pathogens》2020,16(12)
Anopheles mosquitoes have transmitted Plasmodium parasites for millions of years, yet it remains unclear whether they suffer fitness costs to infection. Here we report that the fecundity of virgin and mated females of two important vectors—Anopheles gambiae and Anopheles stephensi—is not affected by infection with Plasmodium falciparum, demonstrating that these human malaria parasites do not inflict this reproductive cost on their natural mosquito hosts. Additionally, parasite development is not impacted by mating status. However, in field studies using different P. falciparum isolates in Anopheles coluzzii, we find that Mating-Induced Stimulator of Oogenesis (MISO), a female reproductive gene strongly induced after mating by the sexual transfer of the steroid hormone 20-hydroxyecdysone (20E), protects females from incurring fecundity costs to infection. MISO-silenced females produce fewer eggs as they become increasingly infected with P. falciparum, while parasite development is not impacted by this gene silencing. Interestingly, previous work had shown that sexual transfer of 20E has specifically evolved in Cellia species of the Anopheles genus, driving the co-adaptation of MISO. Our data therefore suggest that evolution of male-female sexual interactions may have promoted Anopheles tolerance to P. falciparum infection in the Cellia subgenus, which comprises the most important malaria vectors. 相似文献
72.
D Barbier D Perrine C Duhamel R Doublet P Georges 《Applied and environmental microbiology》1990,56(5):1420-1422
A modification of the FAUST technique allowed a highly regular recovery of Taenia saginata eggs from sewage sludge, as well as their quantification. Despite the low viability (8%) noted, the viable T. saginata egg level remains high (20.10(6)/ha) and offers a serious risk for cattle even after a 3-week "no-grazing" period. 相似文献
73.
This research is relevant to oral processing of lipid continuous foods. During this first step of food digestion, lipid continuous foods such as chocolate or margarine phase invert into oil-in-water emulsions stimulated through the mechanical action of tongue and teeth in combination with the change in temperature and the high surface activity of salivary proteins. These are hypothesised to stabilise the newly formed interface in competition with surfactants or surface active molecules released from the food if present. Here competitive adsorption between mechanically stimulated human whole saliva (HWS) and lecithin dissolved in sunflower oil freed of interfacially active contaminants was investigated in-vitro using a pendant drop tensiometer for dynamic interfacial tension and interfacial rheological measurements. Initially, it was validated that the interfacial properties of HWS samples remained unaffected by frozen storage at ?80 °C during 6 weeks. Protein concentration affected the absolute values of interfacial tension and in particular the dilatational elastic modulus. Competitive adsorption studies revealed a mixed interface and it follows that emulsion stabilisation during oral processing involves both salivary proteins and lecithin present in the oil phase. 相似文献
74.
Expression patterns of nm23 genes during mouse organogenesis 总被引:2,自引:0,他引:2
Nucleoside di-phosphate kinase enzyme (NDPK) isoforms, encoded by the nm23 family of genes, may be involved in various cellular differentiation and proliferation processes. We have therefore analyzed
the expression of nm23-M1, -M2, -M3, and -M4 during embryonic mouse development. In situ hybridization data has revealed the differential expression of nm23 mRNA during organogenesis. Whereas nm23-M1 and -M3 are preferentially expressed in the nervous and sensory systems, nm23-M2 mRNA is found ubiquitously. Irrespective of the developmental state studied, nm23-M4 mRNA is only expressed at low levels in a few embryonic organs. In the cerebellum and cerebral cortex, nm23-M1, -M2, and -M3 are present in the neuronal differentiation layer, whereas nm23-M4 mRNA is distributed in the proliferating layer. Thus, nm23 mRNA is differentially expressed, and the diverse NDPK isoforms are sequentially involved in various developmental processes. 相似文献
75.
Physiochemical properties of the Vi antigen before and after mild alkaline hydrolysis 总被引:4,自引:1,他引:3 下载免费PDF全文
Sedimentation and diffusion constants were determined for electrophoretically purified Vi antigen before and after mild alkaline hydrolysis. The molecular weight of the intact antigen was found to be 1.7 × 106. Mild alkaline hydrolysis completely removed O-acetyl, reduced the molecular weight to 1.0 × 105, and lowered the intrinsic viscosity from 8.0 deciliters/g to approximately 0.5 deciliter/g. Infrared spectra of the two antigen preparations were also compared. 相似文献
76.
Incorporating climate change into ecosystem service assessments and decisions: a review 总被引:3,自引:0,他引:3 下载免费PDF全文
Rebecca K. Runting Brett A. Bryan Laura E. Dee Fleur J. F. Maseyk Lisa Mandle Perrine Hamel Kerrie A. Wilson Kathleen Yetka Hugh P. Possingham Jonathan R. Rhodes 《Global Change Biology》2017,23(1):28-41
Climate change is having a significant impact on ecosystem services and is likely to become increasingly important as this phenomenon intensifies. Future impacts can be difficult to assess as they often involve long timescales, dynamic systems with high uncertainties, and are typically confounded by other drivers of change. Despite a growing literature on climate change impacts on ecosystem services, no quantitative syntheses exist. Hence, we lack an overarching understanding of the impacts of climate change, how they are being assessed, and the extent to which other drivers, uncertainties, and decision making are incorporated. To address this, we systematically reviewed the peer‐reviewed literature that assesses climate change impacts on ecosystem services at subglobal scales. We found that the impact of climate change on most types of services was predominantly negative (59% negative, 24% mixed, 4% neutral, 13% positive), but varied across services, drivers, and assessment methods. Although uncertainty was usually incorporated, there were substantial gaps in the sources of uncertainty included, along with the methods used to incorporate them. We found that relatively few studies integrated decision making, and even fewer studies aimed to identify solutions that were robust to uncertainty. For management or policy to ensure the delivery of ecosystem services, integrated approaches that incorporate multiple drivers of change and account for multiple sources of uncertainty are needed. This is undoubtedly a challenging task, but ignoring these complexities can result in misleading assessments of the impacts of climate change, suboptimal management outcomes, and the inefficient allocation of resources for climate adaptation. 相似文献
77.
78.
79.
Lisa C. Hennemann Shantelle L. LaFayette Julien K. Malet Perrine Bortolotti Tianxiao Yang Geoffrey A. McKay Daniel Houle Danuta Radzioch Simon Rousseau Dao Nguyen 《PLoS pathogens》2021,17(3)
Pseudomonas aeruginosa causes chronic airway infections, a major determinant of lung inflammation and damage in cystic fibrosis (CF). Loss-of-function lasR mutants commonly arise during chronic CF infections, are associated with accelerated lung function decline in CF patients and induce exaggerated neutrophilic inflammation in model systems. In this study, we investigated how lasR mutants modulate airway epithelial membrane bound ICAM-1 (mICAM-1), a surface adhesion molecule, and determined its impact on neutrophilic inflammation in vitro and in vivo. We demonstrated that LasR-deficient strains induce increased mICAM-1 levels in airway epithelial cells compared to wild-type strains, an effect attributable to the loss of mICAM-1 degradation by LasR-regulated proteases and associated with enhanced neutrophil adhesion. In a subacute airway infection model, we also observed that lasR mutant-infected mice displayed greater airway epithelial ICAM-1 expression and increased neutrophilic pulmonary inflammation. Our findings provide new insights into the intricate interplay between lasR mutants, LasR-regulated proteases and airway epithelial ICAM-1 expression, and reveal a new mechanism involved in the exaggerated inflammatory response induced by lasR mutants. 相似文献
80.
Improvement of RT-PCR detection of chronic bee paralysis virus (CBPV) required by the description of genomic variability in French CBPV isolates 总被引:2,自引:0,他引:2
Blanchard P Olivier V Iscache AL Celle O Schurr F Lallemand P Ribière M 《Journal of invertebrate pathology》2008,97(2):182-185
A new RT-PCR test has been developed to diagnose Chronic bee paralysis virus (CBPV) that is able to detect genetically variable viral isolates. In fact, up to 8.7% divergence between partial nucleotide sequences from viral isolates from French honey bees was highlighted in a preliminary variability study. The previously-described RT-PCR was unable to detect all these viral isolates and RT-PCR diagnosis needed improvement. The new RT-PCR test can detect up to 40% more CBPV isolates. 相似文献