全文获取类型
收费全文 | 157篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
166篇 |
出版年
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 11篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2001年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1990年 | 3篇 |
1986年 | 2篇 |
1982年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1972年 | 3篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1966年 | 3篇 |
1958年 | 2篇 |
1957年 | 6篇 |
1956年 | 3篇 |
1955年 | 3篇 |
1954年 | 2篇 |
1952年 | 2篇 |
1951年 | 4篇 |
1950年 | 3篇 |
1949年 | 2篇 |
1948年 | 2篇 |
1936年 | 2篇 |
1934年 | 2篇 |
1930年 | 2篇 |
1928年 | 2篇 |
1926年 | 2篇 |
1925年 | 3篇 |
1924年 | 1篇 |
1923年 | 3篇 |
排序方式: 共有166条查询结果,搜索用时 15 毫秒
31.
Background
Understanding evolutionary processes that drive genome reduction requires determining the tempo (rate) and the mode (size and types of deletions) of gene losses. In this study, we analysed five endosymbiotic genome sequences of the gamma-proteobacteria (three different Buchnera aphidicola strains, Wigglesworthia glossinidia, Blochmannia floridanus) to test if gene loss could be driven by the selective importance of genes. We used a parsimony method to reconstruct a minimal ancestral genome of insect endosymbionts and quantified gene loss along the branches of the phylogenetic tree. To evaluate the selective or functional importance of genes, we used a parameter that measures the level of adaptive codon bias in E. coli (i.e. codon adaptive index, or CAI), and also estimates of evolutionary rates (Ka) between pairs of orthologs either in free-living bacteria or in pairs of symbionts. 相似文献32.
33.
Galbeta1-3GalNAc (T-disaccharide) and related molecules were assayed to
describe the structural requirements of carbohydrates to bind Agaricus
bisporus lectin (ABL). Results provide insight into the most relevant
regions of T-disaccharide involved in the binding of ABL. It was found that
monosaccharides bind ABL weakly indicating a more extended
carbohydrate-binding site as compared to those involvedin the T-
disaccharide specific lectins such as jacalin and peanut agglutinin.
Lacto-N-biose (Galbeta1-3GlcNAc) unlike T-disaccharide, is unable to
inhibit the ABL interaction, thus showing the great importance of the
position of the axial C-4 hydroxyl group of GalNAc in T-disaccharide. This
finding could explain the inhibitory ability of Galbeta1-6GlcNAc and
lactose because C-4 and C-3 hydroxyl groups of reducing Glc, respectively,
occupy a similar position as reported by conformational analysis. From the
comparison of different glycolipids bearing terminal T-disaccharide bound
to different linkages, it can be seen than ABL binding is even more
impaired by an adjacent C-6 residual position than by the anomeric
influence of T-disaccharide. Furthermore, the addition of beta-GlcNAc to
the terminal T-disaccharide in C-3 position of Gal does not affect the ABL
binding whereas if an anionic group such as glucuronic acid is added to
C-3, the binding is partially affected. These findings demonstrate that ABL
holds a particular binding nature different from that of other
T-disaccharide specific lectins.
相似文献
34.
35.
36.
37.
Background
The Mycobacterium tuberculosis 19-kDa lipoprotein has been reported to stimulate both T and B cell responses as well as induce a number of Th1 cytokines. In order to evaluate the Mycobacterium avium subsp. paratuberculosis (M. avium subsp. paratuberculosis) 19-kDa lipoprotein as an immunomodulator in cattle with Johne's disease, the gene encoding the 19-kDa protein (MAP0261c) was analyzed. 相似文献38.
39.
A NOTE ON THE FLORAL ANATOMY OF RIVINA HUMILIS L. 总被引:1,自引:0,他引:1
EDITH R. SAUNDERS 《The New phytologist》1934,33(1):66-67
40.
EDITH R. SAUNDERS 《The New phytologist》1934,33(2):127-169