首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   78篇
  免费   5篇
林业   19篇
农学   1篇
  13篇
农作物   10篇
水产渔业   17篇
畜牧兽医   21篇
植物保护   2篇
  2020年   2篇
  2019年   1篇
  2018年   5篇
  2017年   2篇
  2016年   3篇
  2015年   3篇
  2014年   2篇
  2013年   7篇
  2012年   8篇
  2011年   8篇
  2010年   1篇
  2009年   14篇
  2008年   5篇
  2007年   2篇
  2006年   3篇
  2005年   3篇
  2004年   3篇
  2003年   2篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1985年   1篇
  1979年   2篇
  1978年   2篇
排序方式: 共有83条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Considering monkeys are animals closely related to the human, and semitendinosus muscle has been used in many postural research experiments, we have decided to study its histochemical characteristics. Samples were removed from the proximal, middle and distal regions of the semitendinosus muscles of five adult male tufted capuchin monkeys and observed for reaction with m-ATPase (with alkaline and acid pre-incubation), nicotinamide adenine dinucleotide tetrazolium reductase, and haematoxylin and eosin. The muscle fibres were classified as fast glycolytic (FG), fast oxidative glycolytic (FOG) and slow oxidative (SO) and quantified in terms of frequency and area. The three regions of the semitendinosus muscle showed no significant differences in frequency or area of the respective fibre types, and therefore the muscle can be considered histoenzymologically homogeneous. FG fibres presented higher frequencies and larger areas. The sum of FOG and SO fibres was 57.5%, suggesting that the semitendinosus muscle of the tufted capuchin monkey is adapted to an action involved in posture maintenance and in long arboreal dislocation. The present data agrees with the notion of differentiated quadrupedalism in some primates, which support a lower percentage of their weight on the fore limbs.  相似文献   
5.
This study determined the effects of oil processing conditions on functional properties of milkweed seed proteins to evaluate their potential for value-added uses. Flaked milkweed seeds were cooked at 82 °C (180 °F) for 30, 60 or 90 min in the seed conditioner, and then screw-pressed to extract the oil. Proximate composition and protein functional properties of cooked flakes and press cakes were determined and compared with those of unprocessed ground, defatted milkweed seeds. Milkweed seed protein was most soluble at the pH range of 7–10, had excellent emulsifying properties, and produced substantial but highly unstable foams. Heat applied during seed cooking and screw-pressing did not reduce protein solubility and improved emulsifying, foaming, and water-holding capacities. Emulsifying capacity was much higher at pH 10 than at pH 7. These results showed that the protein in both the milkweed seed and its press cake from oil processing has useful functional properties that could be utilized in applications such as paint emulsifier and adhesive extender.  相似文献   
6.
Roque  Róger Moya 《New Forests》2004,28(2-3):299-307
New Forests - Gmelina arborea Roxb. (gmelina) was introduced in Costa Rica in the late 1960s. At the present time, gmelina is the most widely planted tree species in Costa Rica. According to...  相似文献   
7.
When the effect of calcium on the oxidation of linoleic acid by potato tuber 5-lipoxygenase (LOX) was investigated, it was seen to promote the enzyme's activity at pH values higher than the optimum pH of 6.3, resulting in an enzyme activation at alkaline pH. Kinetic analysis of calcium activation at different pH values revealed that the cation abolished the inhibition by high substrate concentration, which occurs in the absence of Ca(2+), thus leading to activation at high substrate concentration. Studies were conducted to investigate the influence of Ca(2+) on the physicochemical nature of the substrate and its effect on the LOX activity expression. It was concluded that the aggregation mode rather than the aggregation state of linoleic acid is responsible for potato 5-LOX changes.  相似文献   
8.
Empirical, statistically based models were used to describe the growth and development of Eucalyptus nitens plantations for a range of site productivities and the standard biomass and pulp silvicultural regime currently applied in Northern Spain. The results obtained, along with data gathered from a network of 68 plots, 48 trees felled for biomass estimations and 73 trees sampled for foliar area estimation were used to parameterize the 3-PG model for this species in Northern Spain. Most parameters associated with allometric relationships and partitioning (i.e. bark and branch fraction, basic density, age modifier and mortality) were derived from local data, and the remaining parameters were obtained from published studies on E. nitens or default values previously used for E. globulus. The parameterized model was validated with data from three trials measured from age 3 years until age 8-14 years, and performed better than the empirical model in terms of total stand under bark volume, mean diameter at breast height, basal area and foliar biomass. The process-based model was then used to forecast changes in plantations subjected to a clearwood regime, initializing the model at age 3 years, considering 3 prunings, 2 thinnings and lengthening the rotation to 18 years. This integrated regime was able to provide biomass for bioenergy, pulp or fibreboard wood and also solid wood, with thinning operations assisting the financial viability, and was a potentially good alternative for productive sites.  相似文献   
9.
Ultrasonographic measurements were made at least once a month during 14 gestations in seven Tursiops truncatus and 12 gestations in five Tursiops aduncus (bottlenosed dolphins). The 121 measurements of the fetal biparietal diameter and 139 measurements of the fetal thoracic diameter in T truncatus and the 97 measurements of the biparietal diameter and 97 measurements of the thoracic diameter in Taduncus were used to establish regression lines for the increases in the diameter of the head and thorax of the fetus with time. From these relationships an easy-to-use computer program was developed to predict the date of birth of the two species of bottlenosed dolphin, and its predictions were compared with the actual dates of birth of other calves of both species. The births occurred within the range of predicted dates, and even when only a few measurements were available, the program provided accurate predictions.  相似文献   
10.
The β-ketoadipate pathway is the major route for degradation of aromatic compounds by various soil microorganisms. Protocatechuate 3,4-dioxygenase, a key enzyme of this pathway and which is encoded by pcaGH genes, catalyses the ring cleavage of protocatechuate. Microorganisms harbouring pcaGH genes are widely distributed in the environment but little is known about their relative abundance within the total microflora. Hence, this paper reports the development of a real-time PCR assay to quantify the bacterial pcaH sequence that encodes the β sub-unit of the protocatechuate 3,4-dioxygenase. This real-time PCR assay was linear over seven orders of magnitude with a calculated efficiency of 99% and sensitive up to 102 copies of the pcaH sequence per assay. Real-time PCR analyses performed on six soils with different physico-chemical properties, revealed pcaH densities ranging from 103 to 104 copies of pcaH  ng−1 of soil DNA, which corresponded to approximately 0.2–10.9% of the total bacterial community. The sequencing of real-time PCR amplicons yielded 48 deduced amino acid sequences that exhibited 44–100% identity to known bacterial PcaH sequences, thereby confirming the accuracy of this real-time PCR assay.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号