全文获取类型
收费全文 | 49篇 |
免费 | 7篇 |
专业分类
林业 | 2篇 |
农学 | 1篇 |
5篇 | |
综合类 | 4篇 |
农作物 | 2篇 |
畜牧兽医 | 37篇 |
植物保护 | 5篇 |
出版年
2023年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2013年 | 8篇 |
2012年 | 2篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2007年 | 1篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 4篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1957年 | 1篇 |
1948年 | 1篇 |
1939年 | 1篇 |
排序方式: 共有56条查询结果,搜索用时 265 毫秒
51.
Two lettuce cultivars (Lactuca sativa L., cv. Calmar and cv. Climax) were selected to compare their tolerance to salt stress. The plants were grown in a hydroponic system using a 0.5 modified Hoagland solution. Treatments of 0, 40, 80, and 120 mol m–3 NaCl or 0 and 20 mol m–3 Na2SO4 were started when the second leaf above the cotyledons appeared. The plants were harvested 20 days later. Climax showed a greater tolerance to salinity at the 40 mol m–3 NaCl concentration; the % decrease in both shoot and root fresh weight was significantly less than Calmar. No differences between the cultivars were found in the Na2SO4 experiments. Differences in root Cl– content at the 40 mol m–3 concentration corresponded to an enhanced water content of the roots. A mechanism for the observed differences in salt tolerance between the two cultivars is discussed. 相似文献
52.
Abstract An unusual response vas noted in the salinized nutrient solutions of lettuce (Lactuca sativa L.) in that they became clear yellow in color. This condition also developed in experiments using polyethylene glycol in place of salt, suggesting that the response vas due to the osmotic stress imposed upon the roots. Photometric and fluorometric determinations indicated that the color could be attributed to a flavin‐like compound or compounds released by the roots. 相似文献
53.
Kieren D. Rix Alistair J. Gracie Bradley M. Potts Phillip H. Brown Cameron J. Spurr Peter L. Gore 《Annals of Forest Science》2012,69(6):673-679
Context
High temperature stress in nurseries germinating Eucalyptus globulus seed is an important problem affecting germination synchrony and rate. Where there is a risk of high-temperature stress, then the choice of female parent may be important. This issue is particularly relevant to the production of full-sib families from mass-supplementary pollination where there may be opportunities for seed producers to manipulate the directionality of the crossing done in seed orchards.Aims
This study aimed to quantify the maternal versus paternal influence of seed sensitivity to high temperature stress during germination.Methods
A diallel crossing scheme involving four genotypes was used to test the relative importance of male and female genetic influences on the germination and development of E. globulus seed and their response to high temperature stress. Seed was germinated at optimum (25°C) and supra-optimal (32°C and 37°C) temperatures, and six traits describing the proportion and rate of seed germination and early seedling development were assessed.Results
Both paternal and maternal effects affected the germination response, arguing for at least some influence of the nuclear genotype of the embryo. However, the response to high temperature stress was more influenced by the maternal than paternal parent.Conclusion
Both the male and female genotype may affect various aspects of seed germination and early seedling development independent of seed size; however, some facets of the germination response will be mainly affected by the female parent. 相似文献54.
55.
56.
Successful vaccination of sheep against footrot and attempts to eradicate the disease depend on there being a limit to the antigenic diversity of the causative bacterium, Bacteroides nodosus. Fimbrial antigenic variation was therefore investigated in vivo, both under conditions of chronic infection and under the pressure of a vaccine-induced immune response, to ascertain whether this represented an obstacle to such goals. Material was available from 5 experiments and although B. nodosus appeared to have undergone changes in its fimbrial antigens in one of these, the possibility that superinfection was responsible for the variation detected could not be ruled out because all sheep in this case were maintained at pasture. Overall, the results provided no evidence of fimbrial antigenic shift in B. nodosus in vivo and in conclusion, the survival of the organism in the sheep's foot, both in long-term natural infection and following vaccination, must therefore be related to factors other than the ability to undergo antigenic variation in order to evade the host's immune response. 相似文献