全文获取类型
收费全文 | 548篇 |
免费 | 61篇 |
出版年
2022年 | 5篇 |
2019年 | 5篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 12篇 |
2014年 | 16篇 |
2013年 | 23篇 |
2012年 | 27篇 |
2011年 | 30篇 |
2010年 | 16篇 |
2009年 | 17篇 |
2008年 | 21篇 |
2007年 | 22篇 |
2006年 | 21篇 |
2005年 | 19篇 |
2004年 | 13篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 18篇 |
2000年 | 23篇 |
1999年 | 18篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 12篇 |
1992年 | 18篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 16篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1979年 | 8篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1975年 | 7篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1971年 | 5篇 |
1970年 | 3篇 |
1968年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有609条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Genetic diversity and the way a species is introduced influence the capacity of
populations of invasive species to persist in, and adapt to, their new environment. The
diversity of introduced populations affects their evolutionary potential, which is
particularly important for species that have invaded a wide range of habitats and
climates, such as European gorse, Ulex europaeus. This species originated in the
Iberian peninsula and colonised Europe in the Neolithic; over the course of the past two
centuries it was introduced to, and has become invasive in, other continents. We
characterised neutral genetic diversity and its structure in the native range and in
invaded regions. By coupling these results with historical data, we have identified the
way in which gorse populations were introduced and the consequences of introduction
history on genetic diversity. Our study is based on the genotyping of individuals from 18
populations at six microsatellite loci. As U. europaeus is an allohexaploid
species, we used recently developed tools that take into account genotypic ambiguity. Our
results show that genetic diversity in gorse is very high and mainly contained within
populations. We confirm that colonisation occurred in two stages. During the first stage,
gorse spread out naturally from Spain towards northern Europe, losing some genetic
diversity. During the second stage, gorse was introduced by humans into different regions
of the world, from northern Europe. These introductions resulted in the loss of rare
alleles but did not significantly reduce genetic diversity and thus the evolutionary
potential of this invasive species. 相似文献
85.
86.
Maria J. Gomez-Lamarca Julia Falo-Sanjuan Robert Stojnic Sohaib Abdul Rehman Leila Muresan Matthew L. Jones Zoe Pillidge Gustavo Cerda-Moya Zhenyu Yuan Sarah Baloul Phillippe Valenti Kerstin Bystricky Francois Payre Kevin OHolleran Rhett Kovall Sarah J. Bray 《Developmental cell》2018,44(5):611-623.e7
87.
Axially chiral Ni(II) complexes of α‐amino acids: Separation of enantiomers and kinetics of racemization
下载免费PDF全文
![点击此处可从《Chirality》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wenzhong Zhang Romuald Eto Ekomo Christian Roussel Hiroki Moriwaki Hidenori Abe Jianlin Han Vadim A. Soloshonok 《Chirality》2018,30(4):498-508
Herein we present design, synthesis, chiral HPLC resolution, and kinetics of racemization of axially chiral Ni(II) complexes of glycine and di‐(benzyl)glycine Schiff bases. We found that while the ortho‐fluoro derivatives are configurationally unstable, the pure enantiomers of corresponding axially chiral ortho‐chloro‐containing complexes can be isolated by preparative HPLC and show exceptional configurational stability (t1/2 from 4 to 216 centuries) at ambient conditions. Synthetic implications of this discovery for the development of new generation of axially chiral auxiliaries, useful for general asymmetric synthesis of α‐amino acids, are discussed. 相似文献
88.
89.
Unravelling the mechanisms of a protein refolding process based on the association of detergents and co‐solvents
下载免费PDF全文
![点击此处可从《Journal of peptide science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
C. Michaux G. Roussel M. Lopes‐Rodrigues A. Matagne E.A. Perpète 《Journal of peptide science》2016,22(7):485-491
A new technique associating the detergent Sodium Dodecyl Sulphate (SDS) and an alcohol‐type co‐solvent has been set up, showing an unexpected efficiency to refold several types of soluble or membrane proteins. The present contribution deepens the fundamental knowledge on the phenomena underlying this process, considering the refolding of two model peptides featuring the main protein secondary structures: α‐helix and β‐sheet. Their refolding was monitored by fluorescence and circular dichroism, and it turns out that: (i) 100% recovery of the folded structure is observed for both peptides, (ii) the highest the SDS concentration, the more co‐solvent to be added to recover the peptides' native structures, (iii) a high alcohol concentration is required to alter the SDS denaturing properties, (iv) the co‐solvent performance relies on its specific lipophilic–hydrophilic balanced character, (v) the size of the micelle formed by the detergent does not enter the process critical parameters, and (vi) increasing the salt concentration up to 1 M NaCl has a beneficial impact on the process efficiency. These mechanistic aspects will help us to improve the method and extend its application. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
90.
Pseudomonas aeruginosa plays an important role in the colonization of the airways of patients suffering from cystic fibrosis. It binds to the carbohydrate part of respiratory and salivary mucins and its binding to cystic fibrosis mucins is even higher, suggesting that qualitative or/and quantitative modifications of the carbohydrate chains may be involved in this process. In order to find out the best carbohydrate receptors for P.aeruginosa, a flow cytometry technique using a panel of polyacrylamide based glycoconjugates labeled with fluorescein was developed. The neoglycoconjugates contained neutral, sialylated or sulfated chains analogous to carbohydrate determinants found at the periphery of respiratory mucins (Le(a), Le(y), Le(x), sialyl- and 3'-sulfo-Le(x), and blood group A determinants). We used also neoglycoconjugates containing Gal(alpha1-2)Galbeta and sialyl- N -acetyllactosamine determinants. The interaction of these glycoconjugates with the nonpiliated strain of P.aeruginosa, 1244-NP, was saturable except for the glycoconjugates containing blood group A or sialyl- N -acetyllactosamine epitopes. The measure of Kd indicated that strain 1244-NP had a higher affinity for the glycoconjugate bearing the sialyl-Le(x)determinant than for all the other glycoconjugates studied. The role of sialic acid was confirmed by competition assay using mainly sialylated mucin glycopeptides. In order to find out if this behavior was the same for pathological strains as for the 1244-NP mutant, four mucoid strains of P.aeruginosa isolated from cystic fibrosis patients were analyzed with the Le(x)neoglycoconjugate, its sialylated and its sulfated derivatives. Individual variations in the binding of these strains to the three glycoconjugates were observed. However, three strains out of four had a higher affinity for the sialyl-Le(x)than for the 3'-sulfo-Le(x)derivative. 相似文献