全文获取类型
收费全文 | 540篇 |
免费 | 90篇 |
出版年
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 17篇 |
2012年 | 29篇 |
2011年 | 14篇 |
2010年 | 26篇 |
2009年 | 16篇 |
2008年 | 22篇 |
2007年 | 35篇 |
2006年 | 16篇 |
2005年 | 19篇 |
2004年 | 15篇 |
2003年 | 18篇 |
2002年 | 12篇 |
2001年 | 14篇 |
2000年 | 20篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 12篇 |
1988年 | 13篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1971年 | 11篇 |
1969年 | 10篇 |
1968年 | 9篇 |
1966年 | 6篇 |
排序方式: 共有630条查询结果,搜索用时 15 毫秒
51.
Development and Evaluation of Methods To Detect Nucleopolyhedroviruses in Larvae of the Douglas-Fir Tussock Moth, Orgyia pseudotsugata (McDunnough)
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Christine M. Thorne Imre S. Otvos Nicholas Conder David B. Levin 《Applied microbiology》2007,73(4):1101-1106
Various molecular methods are used to detect pathogenic microorganisms and viruses within their hosts, but these methods are rarely validated by direct comparison. Southern hybridization, enzyme-linked immunosorbent assay (ELISA), and a novel DNA extraction/PCR assay were used to detect Orgyia pseudotsugata multiple nucleopolyhedrovirus (OpMNPV) in Douglas-fir tussock moth larvae. PCR was more sensitive than Southern hybridization and ELISA at detecting semipurified virus. ELISA, however, was the most accurate method for detecting virus within larvae, given that Southern hybridization and PCR produced false-negative results (31% and 2.5%, respectively). ELISA may be preferable in some applications because virus infections can be quantified (r2 = 0.995). These results may be applicable to both applied and academic research that seeks to accurately identify the incidence of viruses and microorganisms that regulate insect populations. 相似文献
52.
Xiaoyan Lin Lucy Thorne Zhinan Jin Loubna A. Hammad Serena Li Jerome Deval Ian G. Goodfellow C. Cheng Kao 《Nucleic acids research》2015,43(1):446-460
The replication enzyme of RNA viruses must preferentially recognize their RNAs in an environment that contains an abundance of cellular RNAs. The factors responsible for specific RNA recognition are not well understood, in part because viral RNA synthesis takes place within enzyme complexes associated with modified cellular membrane compartments. Recombinant RNA-dependent RNA polymerases (RdRps) from the human norovirus and the murine norovirus (MNV) were found to preferentially recognize RNA segments that contain the promoter and a short template sequence for subgenomic RNA synthesis. Both the promoter and template sequence contribute to stable RdRp binding, accurate initiation of the subgenomic RNAs and efficient RNA synthesis. Using a method that combines RNA crosslinking and mass spectrometry, residues near the template channel of the MNV RdRp were found to contact the hairpin RNA motif. Mutations in the hairpin contact site in the MNV RdRp reduced MNV replication and virus production in cells. This work demonstrates that the specific recognition of the norovirus subgenomic promoter is through binding by the viral RdRp. 相似文献
53.
54.
The osmotic stress response signalling pathway of the model yeast Saccharomyces cerevisae is crucial for the survival of cells under osmotic stress, and is preserved to varying degrees in other related fungal species. We apply a method for inference of ancestral states of characteristics over a phylogeny to 17 fungal species to infer the maximum likelihood estimate of presence or absence in ancestral genomes of genes involved in osmotic stress response. The same method allows us furthermore to perform a statistical test for correlated evolution between genes. Where such correlations exist within the osmotic stress response pathway of S. cerevisae, we have used this in order to predict and subsequently test for the presence of physical protein-protein interactions in an attempt to detect novel interactions. Finally we assess the relevance of observed evolutionary correlations in predicting protein interactions in light of the experimental results. We do find that correlated evolution provides some useful information for the prediction of protein-protein interactions, but that these alone are not sufficient to explain detectable patterns of correlated evolution. 相似文献
55.
Reproductive or neotenic soldiers of the Archotermopsid Zootermopsis nevadensisnevadensis (Hagen) are compared to sterile soldiers and primary male reproductives. Several head capsule morphometrics correlate significantly with gonad size across all forms and both sexes of soldiers. The easily observed field character of ratio of mandible length to labrum length is a consistent and reliable feature of head capsule external morphology for predicting gonad development and reproductive potential of soldier forms regardless of age, sex, or live weight. 相似文献
56.
Cooper C Thorne A Klein M Conway B Boivin G Haase D Shafran S Zubyk W Singer J Halperin S Walmsley S;CIHR Canadian HIV Trials Network Influenza Vaccine Research Group 《PloS one》2011,6(3):e17758
Introduction
The risk of poor vaccine immunogenicity and more severe influenza disease in HIV necessitate strategies to improve vaccine efficacy.Methods
A randomized, multi-centered, controlled, vaccine trial with three parallel groups was conducted at 12 CIHR Canadian HIV Trials Network sites. Three dosing strategies were used in HIV infected adults (18 to 60 years): two standard doses over 28 days, two double doses over 28 days and a single standard dose of influenza vaccine, administered prior to the 2008 influenza season. A trivalent killed split non-adjuvanted influenza vaccine (Fluviral™) was used. Serum hemagglutinin inhibition (HAI) activity for the three influenza strains in the vaccine was measured to assess immunogenicity.Results
297 of 298 participants received at least one injection. Baseline CD4 (median 470 cells/µL) and HIV RNA (76% of patients with viral load <50 copies/mL) were similar between groups. 89% were on HAART. The overall immunogenicity of influenza vaccine across time points and the three influenza strains assessed was poor (Range HAI ≥40 = 31–58%). Double dose plus double dose booster slightly increased the proportion achieving HAI titre doubling from baseline for A/Brisbane and B/Florida at weeks 4, 8 and 20 compared to standard vaccine dose. Increased immunogenicity with increased antigen dose and booster dosing was most apparent in participants with unsuppressed HIV RNA at baseline. None of 8 serious adverse events were thought to be immunization-related.Conclusion
Even with increased antigen dose and booster dosing, non-adjuvanted influenza vaccine immunogenicity is poor in HIV infected individuals. Alternative influenza vaccines are required in this hyporesponsive population.Trial Registration
ClinicalTrials.gov NCT00764998相似文献57.
The replacement histone H2A.Z in a hyperacetylated form is a feature of active genes in the chicken 总被引:7,自引:1,他引:6
Bruce K Myers FA Mantouvalou E Lefevre P Greaves I Bonifer C Tremethick DJ Thorne AW Crane-Robinson C 《Nucleic acids research》2005,33(17):5633-5639
The replacement histone H2A.Z is variously reported as being linked to gene expression and preventing the spread of heterochromatin in yeast, or concentrated at heterochromatin in mammals. To resolve this apparent dichotomy, affinity-purified antibodies against the N-terminal region of H2A.Z, in both a triacetylated and non-acetylated state, are used in native chromatin immmuno-precipitation experiments with mononucleosomes from three chicken cell types. The hyperacetylated species concentrates at the 5′ end of active genes, both tissue specific and housekeeping but is absent from inactive genes, while the unacetylated form is absent from both active and inactive genes. A concentration of H2A.Z is also found at insulators under circumstances implying a link to barrier activity but not to enhancer blocking. Although acetylated H2A.Z is widespread throughout the interphase genome, at mitosis its acetylation is erased, the unmodified form remaining. Thus, although H2A.Z may operate as an epigenetic marker for active genes, its N-terminal acetylation does not. 相似文献
58.
59.
Kusano KF Pola R Murayama T Curry C Kawamoto A Iwakura A Shintani S Ii M Asai J Tkebuchava T Thorne T Takenaka H Aikawa R Goukassian D von Samson P Hamada H Yoon YS Silver M Eaton E Ma H Heyd L Kearney M Munger W Porter JA Kishore R Losordo DW 《Nature medicine》2005,11(11):1197-1204
Sonic hedgehog (Shh) is a crucial regulator of organ development during embryogenesis. We investigated whether intramyocardial gene transfer of naked DNA encoding human Shh (phShh) could promote a favorable effect on recovery from acute and chronic myocardial ischemia in adult animals, not only by promoting neovascularization, but by broader effects, consistent with the role of this morphogen in embryogenesis. After Shh gene transfer, the hedgehog pathway was upregulated in mammalian fibroblasts and cardiomyocytes. This resulted in preservation of left ventricular function in both acute and chronic myocardial ischemia by enhanced neovascularization, and reduced fibrosis and cardiac apoptosis. Shh gene transfer also enhanced the contribution of bone marrow-derived endothelial progenitor cells to myocardial neovascularization. These data suggest that Shh gene therapy may have considerable therapeutic potential in individuals with acute and chronic myocardial ischemia by triggering expression of multiple trophic factors and engendering tissue repair in the adult heart. 相似文献
60.
AB Chang NC Cox J Purcell JM Marchant PJ Lewindon GJ Cleghorn LC Ee GD Withers MK Patrick J Faoagali 《Respiratory research》2005,6(1):1-5