全文获取类型
收费全文 | 246篇 |
免费 | 34篇 |
出版年
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 10篇 |
2012年 | 10篇 |
2011年 | 19篇 |
2010年 | 13篇 |
2009年 | 12篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 17篇 |
1998年 | 9篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 11篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有280条查询结果,搜索用时 187 毫秒
231.
232.
233.
Combining protein evolution and secondary structure 总被引:19,自引:9,他引:10
An evolutionary model that combines protein secondary structure and amino
acid replacement is introduced. It allows likelihood analysis of aligned
protein sequences and does not require the underlying secondary (or
tertiary) structures of these sequences to be known. One component of the
model describes the organization of secondary structure along a protein
sequence and another specifies the evolutionary process for each category
of secondary structure. A database of proteins with known secondary
structures is used to estimate model parameters representing these two
components. Phylogeny, the third component of the model, can be estimated
from the data set of interest. As an example, we employ our model to
analyze a set of sucrose synthase sequences. For the evolution of sucrose
synthase, a parametric bootstrap approach indicates that our model is
statistically preferable to one that ignores secondary structure.
相似文献
234.
235.
236.
237.
Developmental Genetic Analysis of Contrabithorax Mutations in Drosophila Melanogaster 总被引:3,自引:1,他引:2 下载免费PDF全文
A developmental analysis of the Contrabithorax (Cbx) alleles offers the opportunity to examine the role of the Ultrabithorax (Ubx) gene in controlling haltere, as alternative to wing, morphogenesis in Drosophila. Several Cbx alleles are known with different spatial specificity in their wing toward haltere homeotic transformation. The molecular data on these mutations, however, does not readily explain differences among mutant phenotypes. In this work, we have analyzed the "apogenetic" mosaic spots of transformation in their adult phenotype, in mitotic recombination clones and in the spatial distribution of Ubx proteins in imaginal discs. The results suggest that the phenotypes emerge from early clonality in some Cbx alleles, and from cell-cell interactions leading to recruitment of cells to Ubx gene expression in others. We have found, in addition, mutual interactions between haltere and wing territories in pattern and dorsoventral symmetries, suggesting short distance influences, "accommodation," during cell proliferation of the anlage. These findings are considered in an attempt to explain allele specificity in molecular and developmental terms. 相似文献
238.
239.
240.
A M Jiménez-Monreal F J Aranda V Micol P Sánchez-Pi?era A de Godos J C Gómez-Fernández 《Biochemistry》1999,38(24):7747-7754
The activation of protein kinase C alpha was studied by using a lipid system consisting of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine (POPS) (molar ratio 4:1) and different proportions of 1-palmitoyl-2-oleoyl-sn-glycerol (POG). The phase behavior of the lipidic system was characterized by using differential scanning calorimetry and 31P NMR, and a phase diagram was elaborated. The results suggested the formation of two diacylglycerol/phospholipid complexes, one at 15 mol % of POG and the second at 30 mol % of POG. These two complexes would define the three regions of the phase diagram: in the first region (concentrations of POG lower than 15 mol %) there is gel-gel immiscibility at temperatures below that of the phase transition between C1 and pure phospholipid, and a fluid lamellar phase above of the phase transition. In the second region (between 15 and 30 mol % of POG), gel-gel immiscibility between C1 and C2 with fluid-fluid immiscibility was observed, while inverted hexagonal HII and isotropic phases were detected by 31P NMR. In the third region (concentrations of POG higher than 30 mol %), gel-gel immiscibility seemed to occur between C2 and pure POG along with fluid-fluid immiscibility, while an isotropic phase was detected by 31P NMR. When PKC alpha activity was measured, as a function of POG concentration, maximum activity was found at POG concentrations as low as 5-10 mol %; the activity slightly decreased as POG concentration was increased to 45 mol % at 32 degrees C (above Tc) whereas activity did not change with increasing concentrations of POG at 5 degrees C (below Tc). When the activity was studied as a function of temperature, at different POG concentrations, and depicted as Arrhenius plots, it was found that the activity increased with increasing temperatures, showing a discontinuity at a temperature very close to the phase transition of the system and a lower activation energy at the upper slope of the graph, indicating that the physical state of the membrane affected the interaction of PKC alpha with the membrane. 相似文献