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   48篇
  免费   7篇
林业   3篇
农学   1篇
  16篇
综合类   2篇
农作物   2篇
水产渔业   6篇
畜牧兽医   14篇
植物保护   11篇
  2020年   4篇
  2019年   1篇
  2017年   5篇
  2016年   2篇
  2015年   1篇
  2014年   2篇
  2012年   4篇
  2011年   3篇
  2010年   3篇
  2009年   5篇
  2008年   2篇
  2007年   1篇
  2006年   2篇
  2005年   4篇
  2004年   5篇
  2003年   2篇
  2002年   3篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1994年   1篇
  1988年   1篇
排序方式: 共有55条查询结果,搜索用时 31 毫秒
1.
Studies were conducted in four regions of central Greece (Larisa, Karditsa, Livadia, Thiva), to evaluate the productivity and fibre properties (fibre strength and fibre length) of the five most commonly grown cotton cultivars in these regions. The experiments lasted for 6 years (1995–2000). All the characteristics tested were strongly influenced by the factors ‘year’, ‘cultivar’ and ‘region’. Significant cultivar × region, year × cultivar, region × year and cultivar × region × year interactions occurred for all the characteristics studied. The cultivar Alegria had the highest seed‐cotton and lint yield, while Aria had the lowest ones. Both cultivars gave the highest mean lint percentage but the lowest mean boll weight (MBW). Alegria had the lowest fibre strength, while Aria had the highest. The Acala‐type cultivars, Acala SJ2 and Zeta 2, had intermediate seed‐cotton and lint yield, while Vered 171 had high seed‐cotton and satisfactory lint yield. The three cultivars mentioned above had the highest MBW and very good fibre strength. Positive correlation was observed between fibre strength and length. In spite of the fact that mean fibre length was statistically the same in all cultivars, it was influenced by the factor ‘year’, as a result of different weather conditions. The year 1996 was the most unfavourable one for seed‐cotton yield and MBW, because it was characterized by lower than average air temperatures and rather dry conditions for all study sites. The factor ‘region’, a combination of different climatic conditions and cultural practices, influenced significantly all the parameters studied.  相似文献   
2.
A 4-year (1996–99) survey of the biology of L. serricorne (F) (Coleoptera, Anobiidae) on stored tobacco has taken place in Thessaloniki, northern Greece. For the trapping of the adults, pheromone ('New Serrico' and 'Black Stripe Moth') as well as electric (black light) traps were used. The first generation adults emerging from larvae hibernating inside the tobacco bales appeared flying on the 17/5, 16/5, 28/4, and 30/4 of the years 1996, 1997, 1998, and 1999, respectively. In parallel observations, adults inside the bales were found on the 14/5, 12/5, 23/4, and 26/4 of the above-mentioned years, respectively. Termination of flights, in all the years concerned, took place during October or November, while the last flights of November were recorded in temperatures of about 13°C.  相似文献   
3.
Cryopreservation, a technique of high potential for culture collections, might offer a solution for reliable supply of microalgae in aquaculture units. Marine microalgae used in aquaculture were cryopreserved under 4, −20 and −80 °C using common cryoprotectants (methanol, dimethylsulfoxide (DMSO), propylene glycol and polyvinylpyrrolidone (PVP)) with promising results for Chlorella minutissima, Chlorella stigmatophora, Isochrysis galbana and Dunaliella tertiolecta. As cryoprotectants usually are toxic above certain concentrations and exposure time, and assuming that low amounts of cryoprotectants will remain in regenerated cultures, an experimental scheme was employed to explore the lower limits of safety for these algae and their primary consumers in hatchery food chains. Results showed that methanol was well tolerated by C. stigmatophora and D. tertiolecta up to a concentration of 1.6% (v/v) while I. galbana could not survive in culture at any concentration and C. minutissima exhibited some 30% of the control's yield at 0.2%. DMSO was highly tolerated up to 1.0% by all strains with the Chlorella strains surviving well up to 2%. Propylene glycol was not only tolerated up to 8% by Dunaliella but induced mixotrophic growth as well, while for Isochrysis it was lethal at any concentration. Among zooplanktonic consumers, brine shrimp Artemia nauplii could tolerate very high concentrations of the tested cryoprotectants, the rotifer Brachionus plicatilis was found sensitive to low amounts of PVP, while the nauplii of the shrimp Penaeus japonicus and the crab Eriocheir sinensis were in general very sensitive to all cryoprotectants and in several cases to much lower amounts than 1%. However, as long as the residues of cryoprotectants are kept below 1% in the regenerated cultures, there will be no problem with the animal consumers.  相似文献   
4.
The composition of essential oils from twigs and needles of Balkan pine (Pinus peuce Gris.) grown in northern Greece was investigated. The compounds were identified by using GC-MS analysis. The twig oil was rich in alpha-pinene (7.38%), beta-pinene (12.46%), beta-phellandrene (26.93%), beta-caryophyllene (4.48%), and citronellol (12.48%), and the needle oil was rich in alpha-pinene (23.07%), camphene (5.52%), beta-pinene (22.00%), beta-phellandrene (6.78%), bornyl acetate (9.76%), beta-caryophyllene (3.05%), and citronellol (13.42%). The mean oil yield was 2.85% for twigs and 0. 57% for needles.  相似文献   
5.
The interaction between four flavonoids (catechin, epicatechin, rutin, and quercetin) and bovine serum albumin (BSA) was investigated using tryptophan fluorescence quenching. Quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between the flavonoids and BSA. The binding affinity was strongest for quercetin and ranked in the order quercetin > rutin > epicatechin = catechin. The pH in the range of 5-7.4 does not affect significantly (p < 0.05) the association of rutin, epicatechin, and catechin with BSA, but quercetin exhibited a stronger affinity at pH 7.4 than at lower pH (p < 0.05). Quercetin has a total quenching effect on BSA tryptophan fluorescence at a molar ratio of 10:1 and rutin at approximately 25:1. However, epicatechin and catechin did not fully quench tryptophan fluorescence over the concentration range studied. Furthermore, the data suggested that the association between flavonoids and BSA did not change molecular conformation of BSA and that hydrogen bonding, ionic, and hydrophobic interaction are equally important driving forces for protein-flavonoid association.  相似文献   
6.
To prevent bone loss that occurs with increasing age, nutritional and pharmacological factors are needed. Traditional therapeutic agents (selective estrogen receptor modulators or SERMs, biphosphonates, calcitonin) may have serious side effects or contraindications. In an attempt to find food components potentially acting as SERMs, we submitted four plant aqueous extracts derived from Greek flora (Sideritis euboea, Sideritis clandestina, Marticaria chamomilla, and Pimpinella anisum) in a series of in vitro biological assays reflective of SERM profile. We examined their ability (a) to stimulate the differentiation and mineralization of osteoblastic cell culture by histochemical staining for alkaline phosphatase and Alizarin Red-S staining, (b) to induce, like antiestrogens, the insulin growth factor binding protein 3 (IGFBP3) in MCF-7 breast cancer cells, and (c) to proliferate cervical adenocarcinoma (HeLa) cells by use of MTT assay. Our data reveal that all the plant extracts studied at a concentration range 10-100 microg/mL stimulate osteoblastic cell differentiation and exhibit antiestrogenic effect on breast cancer cells without proliferative effects on cervical adenocarcinoma cells. The presence of estradiol inhibited the antiestrogenic effect induced by the extracts on MCF-7 cells, suggesting an estrogen receptor-related mechanism. In conclusion, the aqueous extracts derived from Sideritis euboea, Sideritis clandestina, Marticaria chamomilla, and Pimpinella anisum may form the basis to design "functional foods" for the prevention of osteoporosis.  相似文献   
7.
The rule of thumb in marine trophodynamics indicates that the bigger an organism, the higher its trophic level (TROPH). This generalization leads to the assumption that fishes increase their TROPH with growth. However, a recent review showed that for many species, TROPH does not increase with body size, suggesting that size‐independent feeding is not rare in marine fishes. Here, we assessed some morphological traits of marine fishes that could potentially be used as indicators for the ability to vary TROPH with body size. Stable isotope values of nitrogen were used as a proxy TROPH. The specific objectives were as follows: (a) to evaluate the relationship between the oral gape and the trophodynamic trend and (b) to quantify the relevance of 11 external morphological traits in determining the size‐based trophodynamics. We used random forest models to identify the morphological traits that would help predict which species would have the potential to increase TROPH with growth and which would have not. The selected traits included the pelvic fin relative position, the dorsal fin shape, total length, and relative mouth size. Our results also showed a marked relationship between the rate of increase in the oral gape and TROPH. The analyses presented here provide the first comprehensive and quantitative review aiming at linking the trophodynamics of marine fishes with external morphological traits.  相似文献   
8.
9.
10.
Simplified algebraic equations are derived to calculate directly the Brooks and Corey model parameters using data obtained from one‐step outflow experiments and saturated hydraulic conductivity. The suggested method has been demonstrated only for horticultural substrates and is verified experimentally for four substrates with satisfactory agreement of the results.  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