全文获取类型
收费全文 | 486篇 |
免费 | 20篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 12篇 |
2017年 | 5篇 |
2016年 | 18篇 |
2015年 | 25篇 |
2014年 | 21篇 |
2013年 | 31篇 |
2012年 | 38篇 |
2011年 | 40篇 |
2010年 | 31篇 |
2009年 | 18篇 |
2008年 | 30篇 |
2007年 | 16篇 |
2006年 | 29篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 27篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 10篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1988年 | 3篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1974年 | 1篇 |
排序方式: 共有506条查询结果,搜索用时 31 毫秒
111.
Bogdan Nowicki Mikael Rhen Vuokko Väisänen-Rhen Auli Pere Timo K. Korhonen 《FEMS microbiology letters》1985,28(3):237-242
Abstract The rate of fimbrial phase variation in Escherichia coli strain 3040 was determined. The strain has type-1 and S fimbriae. The bacterial culture was fractionated into homogeneous subpopulations expressing either one of the fimbrial types only; the subpopulations were inoculated into broth and the fimbriation of individual cells was assayed by immunofluorescence as a function of time. The rate of the shift from S- or type-1-fimbriate cells to non-fimbriate ones was of the order of 10−2 per cell generation and more rapid than a direct shift from one fimbrial phase to another, although both types of phase variations were observed. 相似文献
112.
Fractionation of a bacterial cell population by adsorption to erythrocytes and yeast cells 总被引:1,自引:0,他引:1
Bogdan Nowicki Mikael Rhen Vuokko Väisänen-Rhen Auli Pere Timo K. Korhonen 《FEMS microbiology letters》1985,26(1):35-40
Abstract Fluorochrome-labeled antibodies specific for either S or type-1 fimbriae of Escherichia coli were used to show that in broth culture the two fimbrial types of strain 3040 mostly occurred on different cells. 12% of the cells were nonfimbriated. A fractionation procedure that involved adsorption of bacterial cells onto erythrocytes and yeast cells was developed to isolate homogeneous subpopulations (S-fimbriated, type-1-fimbriated, and non-fimbriated) of. E. coli. The level of contamination in each isolated subpopulation was 4% at the highest. The method is useful in obtaining homogeneous bacterial populations for adherence studies and for purification of specific fimbrial antigens. 相似文献
113.
Antonio Rosato Leonardo Tenori Marta Cascante Pedro Ramon De Atauri Carulla Vitor A. P. Martins dos Santos Edoardo Saccenti 《Metabolomics : Official journal of the Metabolomic Society》2018,14(4):37
Introduction
Metabolomics is a well-established tool in systems biology, especially in the top–down approach. Metabolomics experiments often results in discovery studies that provide intriguing biological hypotheses but rarely offer mechanistic explanation of such findings. In this light, the interpretation of metabolomics data can be boosted by deploying systems biology approaches.Objectives
This review aims to provide an overview of systems biology approaches that are relevant to metabolomics and to discuss some successful applications of these methods.Methods
We review the most recent applications of systems biology tools in the field of metabolomics, such as network inference and analysis, metabolic modelling and pathways analysis.Results
We offer an ample overview of systems biology tools that can be applied to address metabolomics problems. The characteristics and application results of these tools are discussed also in a comparative manner.Conclusions
Systems biology-enhanced analysis of metabolomics data can provide insights into the molecular mechanisms originating the observed metabolic profiles and enhance the scientific impact of metabolomics studies.114.
Aging is associated with increased FGF21 levels but unaltered FGF21 responsiveness in adipose tissue
下载免费PDF全文
![点击此处可从《Aging cell》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alejando Delgado‐Anglés Montserrat Cairó Ricardo Moure Ma Gracia Mateo Joan C. Domingo Pere Domingo Marta Giralt Francesc Villarroya 《Aging cell》2018,17(5)
Fibroblast growth factor 21 (FGF21) has been proposed to be an antiaging hormone on the basis of experimental studies in rodent models. However, circulating FGF21 levels are increased with aging in rodents and humans. Moreover, despite the metabolic health‐promoting effects of FGF21, the levels of this hormone are increased under conditions such as obesity and diabetes, an apparent incongruity that has been attributed to altered tissue responsiveness to FGF21. Here, we investigated serum FGF21 levels and expression of genes encoding components of the FGF21‐response molecular machinery in adipose tissue from healthy elderly individuals (≥70 years old) and young controls. Serum FGF21 levels were increased in elderly individuals and were positively correlated with insulinemia and HOMA‐IR, indices of mildly deteriorated glucose homeostasis. Levels of β‐Klotho, the coreceptor required for cellular responsiveness to FGF21, were increased in subcutaneous adipose tissue from elderly individuals relative to those from young controls, whereas FGF receptor‐1 levels were unaltered. Moreover, total ERK1/2 protein levels were decreased in elderly individuals in association with an increase in the ERK1/2 phosphorylation ratio relative to young controls. Adipose explants from aged and young mice respond similarly to FGF21 “ex vivo”. Thus, in contrast to what is observed in obesity and diabetes, high levels of FGF21 in healthy aging are not associated with repressed FGF21‐responsiveness machinery in adipose tissue. The lack of evidence for impaired FGF21 responsiveness in adipose tissue establishes a distinction between alterations in the FGF21 endocrine system in aging and chronic metabolic pathologies. 相似文献
115.
116.
Summary As part of scaling-up studies for the preparation of antinociceptive neoglycopeptides, the purification of appropriate glycosylated building blocks has been optimized. The synthesis and purification of O-(2,3,4,6,-tetra-O-acetyl-- d-galactopyranosyl/glucopyranosyl)-N
-fluoren-9-yl-methoxycarbonyl-hydroxyproline is described in this paper. The building blocks, suitable for solid-phase synthesis, are obtained in a single chemical step from partially protected hydroxyproline, followed by a rapid and efficient preparative purification. Preparative reversed-phase HPLC conditions have been adjusted to maximize recoveries, while reducing both time and costs of consumables. For the galactosyl conjugate, up to 0.5 g of pure lyophilized building block was obtained from 1.5 g of a crude reaction mixture using plain deionized water and less than 2 l of preparative-grade CH3CN. The glucosyl derivative was even more efficiently purified by spontaneous after-column crystallization from the elution mixture. 相似文献
117.
Joan Rieradevall Xavier Domènech Pere Fullana 《The International Journal of Life Cycle Assessment》1997,2(3):141-144
A case study of a life-cycle assessment (LCA) is performed concerning the treatment of household solid wastes in a landfill.
The stages considered in this LCA study are: goal and scope definition, inventory analysis and impact assessment. The data
of the inventory include the consumption of raw materials and energy through the transport of wastes and the management of
landfill, and the corresponding emissions to the environment. Abiotic resource depletion, global warming, acidification, eutrophication
and human toxicological impacts have been considered as impact categories for the impact assessment phase of the LCA. A comparison
of the environmental impact of the landfilling with and without energy recovery is carried out.
Members of the Spanish Association for LCA Development (APRODACV) 相似文献
118.
119.
Pere Picart Margarita Orejas F. I. Javier Pastor 《World journal of microbiology & biotechnology》2016,32(8):123
The β-glucanase Cel12A gene from Stachybotrys atra has been cloned and heterologously expressed in Aspergillus nidulans and Saccharomyces cerevisiae. The recombinant strains constructed, contained the exonic sequence of cel12A including its own signal peptide coding sequence. SDS-PAGE and zymography revealed that recombinant Cel12A has a molecular mass of 24 kDa which agrees with that deduced from its amino acid sequence, indicating that it is expressed in the non-glycosylated active form. Recombinant A. nidulans showed about eightfold greater activity yield than S. cerevisiae recombinant strain, namely 0.71 and 0.09 β-glucanase Units/ml of culture, respectively. In both host strains most of the activity was secreted to the extracellular media, evidencing the functionality of Cel12A signal peptide in yeast and fungi. This novel signal peptide might facilitate the expression and efficient secretion of other recombinant proteins difficult to secrete. 相似文献
120.
A hydroxyproline-rich glycoprotein (HRGP) component of the maize cell wall was shown to be present in different organs of the plant by extraction of cell wall proteins and detection by Western blotting and immunocytochemistry. Antibodies raised against the protein or against synthetic peptides designed from the protein sequence immunoprecipitated a proline-rich polypeptide which was synthesized in-vitro from poly(A) + RNA extracted from different tissues of the plant and from the complete in-vitro-transcribed mRNA. A very low amount of the protein was found in immature embryos. In particular, the protein could not be detected in the scutellum either by Western blotting or by immunocytochemistry. In agreement with this finding, HRGP mRNA was barely detected in the scutellum, in contrast to its accumulation in the embryo axis. Our results indicate the existence of a unique cell wall structure in embryonic tissues from maize as well as a tissuespecific component of the control of maize HRGP gene expression, distinct to others already described such as cell division.Abbreviations HRGP(s)
hydroxyproline-richglycoprotein(s)
- DAP
days after pollination
The present work was supported by grants from Plan Nacional de Investigation Cientifica y Técnica (grant BI088-0242) and European Communities (grant BAP-374). L.R.-A. is the recipient of a fellowship from the Plan Nacional de Formación de Personal Investigador. 相似文献