全文获取类型
收费全文 | 98篇 |
免费 | 6篇 |
专业分类
104篇 |
出版年
2022年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2015年 | 9篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 11篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有104条查询结果,搜索用时 0 毫秒
101.
Comparison of the effects of concentration, pH and anion species on astringency and sourness of organic acids 总被引:3,自引:1,他引:3
The separate effects of concentration, pH and anion species on intensity of
sourness and astringency of organic acids were evaluated. Judges rated
sourness and astringency intensity of lactic, malic, tartaric and citric
acid solutions at three levels of constant pH varying in normality and at
three levels of constant concentration varying in pH. To assess the
comparative sourness and astringency of the organic acid anions of study,
binary acid solutions matched in pH and titratable acidity were also rated.
As pH was decreased in equinormal solutions, both sourness and astringency
increased significantly (P < 0.001). By contrast, as the normality of
the equi-pH solutions was increased, only sourness demonstrated significant
increases (P < 0.001) while astringency remained constant or decreased
slightly. At the lowest normality tested, all solutions were more
astringent than sour (P < 0.05). Although lactic acid was found to be
significantly more sour than citric acid (P < 0.05), no other sourness
or astringency differences among the organic acid anions were noted. This
study demonstrates for the first time that astringency elicited by acids is
a function of pH and not concentration or anion species, and confirms that
sourness is independently influenced by concentration, pH and anion species
of the acid.
相似文献
102.
Cytokinin-to-Auxin Ratios and Morphology of Shoots and Tissues Transformed by a Chimeric Isopentenyl Transferase Gene 总被引:3,自引:5,他引:3 下载免费PDF全文
Tissues transformed with the isopentenyl transferase (ipt) gene cloned from the T-DNA region of the Ti plasmid or with the ipt gene placed under the control of the cauliflower mosaic virus 35S promoter (35S-ipt) were analyzed for auxin and cytokinin. Free and total indole-3-acetic acid (IAA) levels in 35S-ipt-transformed Nicotiana tabacum and cucumber cells were reduced by 12 to 78% in comparison to untransformed tissues. In contrast, free IAA concentrations in 35S-ipt-transformed Nicotiana plumbaginifolia were almost three times those of untransformed tissues, while total IAA levels were not significantly affected. Cytokinin levels in these antibodies were elevated an average of 300-fold resulting in a 24- to over 2000-fold increase in the cytokinin-to-auxin ratios. High cytokinin-to-auxin ratios correlated with the shooty phenotype of transformed tissues propagated in vitro in the absence of added growth hormones. We conclude that increased endogenous cytokinin-to-auxin ratios can induce cells to undergo morphogenesis and that elevated cytokinin levels can also induce auxin-autonomous growth of transformed tissues without causing a corresponding increase in endogenous IAA levels. 相似文献
103.
104.