全文获取类型
收费全文 | 167篇 |
免费 | 9篇 |
出版年
2021年 | 3篇 |
2018年 | 2篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 12篇 |
2012年 | 14篇 |
2011年 | 17篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有176条查询结果,搜索用时 328 毫秒
81.
Broccardo M Ciotti MT Linari G Agostini S Petrella C Amadoro G Severini C Improta G 《Peptides》2005,26(11):2351-2354
In this study, we investigated the immunocytochemical distribution of NK-1 and NK-3 tachykinin receptors in guinea pig and rat isolated pancreatic acini. In dispersed acinar cells from guinea pig, immunofluorescence staining detected similar densities of NK-1 and NK-3 receptors; conversely, rat acinar cells expressed NK-1 receptors more strongly than NK-3 receptors. In line with previous functional studies, these immunocytochemical findings suggest that guinea pig NK-1 and NK-3 receptors and rat NK-1 receptors alone play a direct stimulatory role in the basal pancreatic acinar amylase release. 相似文献
82.
Polymorphism and divergence at the prune locus in Drosophila melanogaster and D. simulans 总被引:3,自引:0,他引:3
The prune locus of Drosophila melanogaster lies at the tip of the X
chromosome, in a region of reduced recombination in which nearby loci show
reduced variation relative to evolutionary divergence from D. simulans. DNA
sequencing of prune alleles from D. melanogaster and D. simulans reveals
extremely low variation in D. melanogaster but greater variation in D.
simulans. Divergence between the two species is not reduced. This pattern
may be explained by either positive selection leading to hitchhiking of
neutral variation or background selection against deleterious mutations.
The pattern of silent versus replacement polymorphism and divergence at
prune is consistent with either a model of weakly deleterious selection
against amino acid substitutions or balancing selection.
相似文献
83.
Marco Di Luca Luciano Toma Daniela Boccolini Francesco Severini Giuseppe La Rosa Giada Minelli Gioia Bongiorno Fabrizio Montarsi Daniele Arnoldi Gioia Capelli Annapaola Rizzoli Roberto Romi 《PloS one》2016,11(1)
Mosquitoes in the Culex pipiens complex are considered to be involved in the transmission of a range of pathogens, including West Nile virus (WNV). Although its taxonomic status is still debated, the complex includes species, both globally distributed or with a more limited distribution, morphologically similar and characterised by different physiological and behavioural traits, which affect their ability as vectors. In many European countries, Cx. pipiens and its sibling species Culex torrentium occur in sympatry, exhibiting similar bionomic and morphological characters, but only Cx. pipiens appears to play a vector role in WNV transmission. This species consists of two biotypes, pipiens and molestus, which can interbreed when in sympatry, and their hybrids can act as WNV-bridge vectors, due to intermediate ecological features. Considering the yearly WNV outbreaks since 2008 and given the morphological difficulties in recognising species and biotypes, our aim was to molecularly identify and characterised Cx. pipiens and Cx. torrentium in Italy, using recently developed molecular assays. Culex torrentium was not detected; as in other European countries, the pipiens and molestus biotypes were widely found in sympatry with hybrids in most environments. The UPGMA cluster analysis applied to CQ11 genotypic frequencies mainly revealed two groups of Cx. pipiens populations that differed in ecological features. The high propensity of the molestus biotype to exist in hypogean environments, where the habitat’s physical characteristics hinder and preclude the gene flow, was shown. These results confirmed the CQ11 assay as a reliable diagnostic method, consistent with the ecological and physiological aspects of the populations analysed. Since the assessment of the actual role of three biotypes in the WNV circulation remains a crucial point to be elucidated, this extensive molecular screening of Cx. pipiens populations can provide new insights into the ecology of the species and may give useful indications to plan and implement WNV surveillance activities in Italy. 相似文献
84.
The operations involved in the extraction of chorionic somatomammotropin from human placentas cause hemolysis of blood which is present in placental tissue and contamination of crude extract with large amounts of hematic pigments. Most of the pigments are removed by the purification procedure. The portion of purified hCS with high heme content was subjected to treatments with acid acetone and neutral butanone on the basis of procedures generally used for the separation of heme and protein portions in hemoproteins. Both treatments resulted in the removal of heme from hCS; the treatment using butanone was more efficient than the one using acetone. After treatment with both organic solvents, the immunological activity measured with radial immunodiffusion was entirely retained while binding activity on rat ventral prostate particles was slightly decreased. 相似文献
85.
John Schellenberg Matthew G. Links Janet E. Hill Tim J. Dumonceaux Geoffrey A. Peters Shaun Tyler T. Blake Ball Alberto Severini Francis A. Plummer 《Applied and environmental microbiology》2009,75(9):2889-2898
We compared dideoxy sequencing of cloned chaperonin-60 universal target (cpn60 UT) amplicons to pyrosequencing of amplicons derived from vaginal microbial communities. In samples pooled from a number of individuals, the pyrosequencing method produced a data set that included virtually all of the sequences that were found within the clone library and revealed an additional level of taxonomic richness. However, the relative abundances of the sequences were different in the two datasets. These observations were expanded and confirmed by the analysis of paired clone library and pyrosequencing datasets from vaginal swabs taken from four individuals. Both for individuals with a normal vaginal microbiota and for those with bacterial vaginosis, the pyrosequencing method revealed a large number of low-abundance taxa that were missed by the clone library approach. In addition, we showed that the pyrosequencing method generates a reproducible profile of microbial community structure in replicate amplifications from the same community. We also compared the taxonomic composition of a vaginal microbial community determined by pyrosequencing of 16S rRNA amplicons to that obtained using cpn60 universal primers. We found that the profiles generated by the two molecular targets were highly similar, with slight differences in the proportional representation of the taxa detected. However, the number of operational taxonomic units was significantly higher in the cpn60 data set, suggesting that the protein-encoding gene provides improved species resolution over the 16S rRNA target. These observations demonstrate that pyrosequencing of cpn60 UT amplicons provides a robust, reliable method for deep sequencing of microbial communities.Scientific interest in human microbial communities is growing, and basic concepts about the “human microbiome” are evolving rapidly (3, 34). Molecular phylogenetic analysis of 16S rRNA-encoding DNA sequences has revealed a vast diversity of uncultured microbial symbionts that influence animal physiology in ways only beginning to be understood. In particular, microbial species inhabiting the human vagina are thought to play an important role in host health (10). A shift in the composition of the vaginal microbiota from “normal” (Lactobacillus dominated) to a state defined as bacterial vaginosis (BV; increased abundance of gram-negative organisms) is associated with a range of negative outcomes, including pelvic inflammatory disease, preterm births, and the acquisition of sexually transmitted diseases (21, 22, 37). This observation has led to an increased interest in determining the composition of the vaginal microbiota by culture-independent methods (8, 11, 17, 25, 30, 35, 36). However, established cloning and sequencing techniques remain time- and labor-intensive, severely limiting the reach of phylogenetic or functional surveys of microbial communities across body sites, individuals, geographic areas, and scales of time.The advent of next-generation ultra-high-throughput sequencing technologies, in particular, the GS FLX (454 Life Sciences, Branford, CT), has removed an important quantitative barrier in molecular analysis by increasing the number of reads from a gene or genome by orders of magnitude in a single run (20). Unfortunately, the short average length of pyrosequencing reads (∼200 bp compared to ∼700 bp using dideoxy sequencing) presents a new set of problems. The results of recent application of this technology to analysis of 16S rRNA gene sequences from microbes in vaginal samples have demonstrated that short reads are more likely to generate matches to multiple sequences in the rRNA sequence database and that taxonomic and phylogenetic resolution was limited due to strong similarities between 16S rRNA sequences from closely related species (32).An alternative molecular target for microbial identification and phylogenetic analysis is cpn60, a gene that encodes the 60-kDa chaperonin or heat shock protein (HSP60/GroEL) (13). The cpn60 gene is universal in eubacteria and eukaryotes and an extensive, curated reference database is available (13) (http://cpndb.cbr.nrc.ca). The cpn60 universal target (UT) offers key advantages, including short target length (549 to 567 bp), sufficient resolving power to distinguish closely related species and subspecies, and a relatively uniform distribution of variability across the entire length of the target (9, 12). The use of the cpn60 UT has been well established for phylogenetic analysis of complex samples (4, 14) and has recently been applied to vaginal microbial communities (11). In the present study, we examined the feasibility of pyrosequencing for determining the composition of the vaginal microbiota using the cpn60 UT. We compared the microbial community structure generated by pyrosequencing of cpn60 amplicons using the GS FLX with dideoxy sequencing based on clone libraries generated from the same samples. In addition, we evaluated the microbial community profiles generated by pyrosequencing of cpn60 UT amplicons and 16S rRNA amplicons from the same vaginal samples. 相似文献
86.
87.
Nicoline BM Voet Gijs Bleijenberg George W Padberg Baziel GM van Engelen Alexander CH Geurts 《BMC neurology》2010,10(1):56
Background
In facioscapulohumeral dystrophy (FSHD) muscle function is impaired and declines over time. Currently there is no effective treatment available to slow down this decline. We have previously reported that loss of muscle strength contributes to chronic fatigue through a decreased level of physical activity, while fatigue and physical inactivity both determine loss of societal participation. To decrease chronic fatigue, two distinctly different therapeutic approaches can be proposed: aerobic exercise training (AET) to improve physical capacity and cognitive behavioural therapy (CBT) to stimulate an active life-style yet avoiding excessive physical strain. The primary aim of the FACTS-2-FSHD (acronym for Fitness And Cognitive behavioural TherapieS/for Fatigue and ACTivitieS in FSHD) trial is to study the effect of AET and CBT on the reduction of chronic fatigue as assessed with the Checklist Individual Strength subscale fatigue (CIS-fatigue) in patients with FSHD. Additionally, possible working mechanisms and the effects on various secondary outcome measures at all levels of the International Classification of Functioning, Disability and Health (ICF) are evaluated.Methods/Design
A multi-centre, assessor-blinded, randomized controlled trial is conducted. A sample of 75 FSHD patients with severe chronic fatigue (CIS-fatigue ≥ 35) will be recruited and randomized to one of three groups: (1) AET + usual care, (2) CBT + usual care or (3) usual care alone, which consists of no therapy at all or occasional (conventional) physical therapy. After an intervention period of 16 weeks and a follow-up of 3 months, the third (control) group will as yet be randomized to either AET or CBT (approximately 7 months after inclusion). Outcomes will be assessed at baseline, immediately post intervention and at 3 and 6 months follow up.Discussion
The FACTS-2-FSHD study is the first theory-based randomized clinical trial which evaluates the effect and the maintenance of effects of AET and CBT on the reduction of chronic fatigue in patients with FSHD. The interventions are based on a theoretical model of chronic fatigue in patients with FSHD. The study will provide a unique set of data with which the relationships between outcome measures at all levels of the ICF could be assessed.Trial registration
Dutch Trial Register, NTR1447.88.
A cross-regulation between type I IFN and TNFα has been proposed recently, where both cytokines are hypothesized to counteract
each other. According to this model, different autoimmune diseases can be viewed as disequilibrium between both cytokines.
As this model may have important clinical implications, the present review summarizes and discusses the currently available
clinical evidence arguing for or against the proposed cross-regulation between TNFα and type I IFN. In addition, we review
how this cross-regulation works at the cellular and molecular levels. Finally, we discuss the clinical relevance of this proposed
cross-regulation for biological therapies such as type I IFN or anti-TNFα treatment. 相似文献
89.
Lisa GM van Baarsen Carla A Wijbrandts François Rustenburg Tineke Cantaert Tineke CTM van der Pouw Kraan Dominique L Baeten Ben AC Dijkmans Paul P Tak Cornelis L Verweij 《Arthritis research & therapy》2010,12(1):R11
Introduction
Cross-regulation between TNF and type I IFN has been postulated to play an important role in autoimmune diseases. Therefore, we determined the effect of TNF blockade in rheumatoid arthritis (RA) on the type I IFN response gene activity in relation to clinical response. 相似文献90.
In a recent paper written by Hilbe et al (BMC vet res, 2009), the nature and specificity of the prion protein deposition in
the kidney of feline species affected with feline spongiform encephalopathy (FSE) were clearly considered doubtful. This article
was brought to our attention because we published several years ago an immunodetection of abnormal prion protein in the kidney
of a cheetah affected with FSE. At this time we were convinced of its specificity but without having all the possibilities
to demonstrate it. As previously published by another group, the presence of abnormal prion protein in some renal glomeruli
in domestic cats affected with FSE is indeed generally considered as doubtful mainly because of low intensity detected in
this organ and because control kidneys from safe animals present also a weak prion immunolabelling. Here we come back on these
studies and thought it would be helpful to relay our last data to the readers of BMC Vet res for future reference on this
subject. 相似文献