全文获取类型
收费全文 | 111篇 |
免费 | 1篇 |
专业分类
林业 | 6篇 |
农学 | 1篇 |
基础科学 | 1篇 |
47篇 | |
综合类 | 3篇 |
农作物 | 13篇 |
水产渔业 | 11篇 |
畜牧兽医 | 24篇 |
园艺 | 1篇 |
植物保护 | 5篇 |
出版年
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2013年 | 6篇 |
2012年 | 4篇 |
2011年 | 9篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 18篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 11篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有112条查询结果,搜索用时 812 毫秒
61.
Claudia Tonon Adriana Andreu Maria Elvira Aued Marcela Van Damme M. Huarte G. R. Daleo 《Potato Research》1998,41(4):319-325
Summary The kinetics of accumulation of chitinases, glucanases and phytoalexins were studied in two potato cultivars, differing in
their degrees of vertical and horizontal resistance, when infected with two races ofPhytophthora infestans. Tuber disks of cvs Kennebec (susceptible, low horizontal resistance) and Huinkul (tolerant, high horizontal resistance)
were infected with either race “0” (avirulent) or “C” (complex, race 1.3.5.7.11) ofPhytophthora infestans. Extracts of tuber tissue (0–7 days) from cv. Kennebec infected with race “0” showed a strong increase in phytoalexin production
and in chitinase and glucanase activities when compared with those infected with race “C”. These results indicate that race
“C” is able to block defensive reactions. No significant differences were observed in cv. Huinkul infected with both races.
The contribution of these reactions to horizontal resistance is unknown, and our results would not support a conclusive role
for them in the interaction. 相似文献
62.
Abstract – Feeding tactics, body condition and size structure of two populations of pumpkinseed Lepomis gibbosus from Cabañeros National Park (Guadiana River basin, central Spain) were compared to provide insight into the ecological requirements favouring levels of success/failure in relation to human intervention. Habitat, benthic macroinvertebrates and pumpkinseed were quantified in Bullaque (regulated flow, affected by agricultural activities) and Estena (natural conditions) rivers, from May to September of 2005 and 2006. Significant differences were found in the limnological characteristics between the two rivers. Spatial and temporal variations in diet composition were likely related to opportunistic feeding and high foraging plasticity. Diet diversity was higher in Bullaque River. Electivity of benthic prey showed variation between sized individuals and populations. The body condition of pumpkinseed was better in Bullaque River. Current results show that this invasive species is favoured by human intervention in Bullaque River. 相似文献
63.
Pedro L. Castro Rafael Gins David Dominguez Elvira Rey Lidia Robaina Vasileios Karalazos Marisol Izquierdo 《Aquaculture Nutrition》2019,25(1):66-77
To describe the effect and the distribution of zinc in different tissues of a representative marine fish species, gilthead seabreams (Sparus aurata Linnaeus, 1758) were fed different diets containing zinc in different sources (organic, inorganic, encapsulated, blood‐rich diet or fishmeal). The effect was monitored by histology in the lens, liver and intestine. In addition, the anterior and posterior intestine was studied by means of autometallography, a histochemical silver‐based staining method to determine the zinc flow and distribution. The histology of lens did not improve by dietary zinc as there was no occurrence of cataracts. In the liver, the experimental diets were correlated with different changes in the tissue architecture. In the intestine, no histological changes were found using haematoxylin and eosin stain. However, with the use of autometallography stain, it was possible to visualize and describe the route that zinc follows through the enterocytes and the lamina propria. Organic and inorganic zinc diet produced the richest silver deposition in the anterior intestine. 相似文献
64.
Maluta Nathalie Kristine Prado Lopes João Roberto Spotti Fiallo-Olivé Elvira Navas-Castillo Jesús Lourenção André Luiz 《Journal of pest science》2021,94(4):1265-1276
Journal of Pest Science - The whiteflies of the Bemisia tabaci (Genn.) complex (Hemiptera: Aleyrodidae) are serious agricultural pests that cause severe losses to vegetable, ornamental and fiber... 相似文献
65.
Eduardo Vicentin Tatiana Mituti Angélica Maria Nogueira Mônika Fecury Moura Vinicius Henrique Bello Marcos Roberto Ribeiro-Júnior William M. Wintermantel Elvira Fiallo-Olivé Jesús Navas-Castillo Renate Krause-Sakate Jorge Alberto Marques Rezende 《Plant pathology》2022,71(6):1313-1322
The tomato chlorosis virus (ToCV), transmitted by whitefly species of the genera Bemisia and Trialeurodes in a semipersistent manner, causes significant losses in solanaceous crops including tomato (Solanum lycopersicum) and sweet pepper (Capsicum annuum). Worldwide reports of natural and experimental infection of sweet pepper plants with ToCV are contradictory, raising the question of whether the critical factor determining infection is related to the susceptibility of sweet pepper cultivars or the genetics of virus isolates. In this work, ToCV isolates obtained from different hosts and geographical origins were biologically and molecularly analysed, transmitted by B. tabaci MEAM1 and MED, and the reaction of different sweet pepper cultivars was evaluated under different environmental conditions. Brazilian ToCV isolates from tomato, potato (S. tuberosum), S. americanum, and Physalis angulata did not infect plants of five sweet pepper cultivars when transmitted by B. tabaci MEAM1. Temperatures did not affect the sweet pepper susceptibility to tomato-ToCV isolates from São Paulo, Brazil, and Florida, USA. However, sweet pepper-ToCV isolates from Spain and São Paulo, Brazil, were transmitted efficiently to sweet pepper plants by B. tabaci MEAM1 and MED. Although the results indicated that ToCV isolates from naturally infected sweet pepper plants seem to be better adapted to plants of C. annuum, phylogenetic analyses based on the complete nucleotide sequences of RNA1 and RNA2 as well as the p22 gene did not reveal significant nucleotide differences among them. Additional studies are needed to identify intrinsic characteristics of ToCV isolates that favour infection of sweet pepper plants. 相似文献
66.
Zusammenfassung Die K?rnigkeit einer Lebensmitteloberfl?che wird am Beispiel der Kartoffel untersucht. Da eine Gewebeoberfl?che geprüft werden
soll, muss das Prüfgut zun?chst geteilt werden. Als Teilverfahren erweist sich das Schneiden in einer fixierten Vorrichtung
mit einem gespannten Stahldraht bzw. bei hoher Gewebefestigkeit mit einem Messer als am besten geeignet. Optimiert wurden
dabei Schneidwinkel, Schneidgeschwindigkeit und Schneidbewegung. Nach dem Trocknen der Oberfl?che mit Warmluft wird ein m?glichst
formtreuer Abguss der Gewebeoberfl?che erstellt. Zur Bestimmung der Rauheit wird ein Einkufentastsystem (Perthometer S 5 P)
eingesetzt. Die vorgestellte Methode kann als begleitende Untersuchung zur Charakterisierung der K?rnigkeit von Kartoffeln
dienen.
Grundlage: M. Ringenberg, 1985: Rauheitsmessungen an Kartoffelgewebe. Erprobung einer Methode zur Charakterisierung von Kartoffeln.
Freising, Technische Universit?t München-Weihenstephan, Fachgebiet Haushalttechnik, Diplomarbeit. 相似文献
67.
Zhaoqin Wang Haibo Huang Elvira Gonzalez de Mejia Qian Li Vijay Singh 《Cereal Chemistry》2016,93(4):344-351
In the dry‐grind ethanol process, distillers dried grains with solubles (DDGS) is the main coproduct, which is primarily used as an ingredient in ruminant animal diets. Increasing the value of DDGS will improve the profitability of the dry‐grind ethanol process. One way to increase DDGS value is to use pigmented maize as the feedstock for ethanol production. Pigmented maize is rich in anthocyanin content, and the anthocyanin imparts red, blue, and purple color to the grain. It is reported that anthocyanin would be absorbed by yeast cell walls during the fermentation process. The effects of anthocyanin on fermentation characteristics in the dry‐grind process are not known. In this study, the effects of anthocyanin in conventional (conventional starch hydrolyzing enzymes) and modified (granular starch hydrolyzing enzymes [GSHE]) dry‐grind processes were evaluated. The modified process using GSHE replaced high‐temperature liquefaction. The ethanol conversion efficiencies of pigmented maize were comparable to that of yellow dent corn in both conventional (78.4 ± 0.5% for blue maize, 74.3 ± 0.4% for red maize, 81.2 ± 1.0% for purple maize, and 75.1 ± 0.2% for yellow dent corn) and modified dry‐grind processes using GSHE (83.8 ± 0.8% for blue maize, 81.1 ± 0.3% for red maize, 93.5 ± 0.8% for purple maize, and 85.6 ± 0.1% for yellow dent corn). Total anthocyanin content in DDGS from the modified process was 1.4, 1.9, and 2.4 times of that from the conventional process for purple, red, and blue maize samples, respectively. These results indicated that pigmented maize rich in anthocyanin did not negatively affect the fermentation characteristics of the dry‐grind process and that there was a potential to use pigmented maize in the dry‐grind process, especially when using GSHE. 相似文献
68.
Martha Böttcher Benita Kluge Karin Tomalak Elvira Meyer W. Lange 《Reproduction in domestic animals》1992,27(2):101-111
Inhalt Follikelflüssigkeit aus Follikeln des Rindes am Tag des Östrus gewonnen, wurde als Serumanalogon zum Kultivierungsmedium TCM 199 zugesetzt. Die Supplementierung des TCM mit 20%östrischer Follikelflüssigkeit (ÖFF) in der Reifungsphase und während der Zygotenkultivierung erbrachte 6–7 Tage post inseminationem einen Anteil an Morulae und Blastozysten von 41,7% (30,8–47,8%). Eine Reduzierung des Anteils ÖFF auf 10% zog einen Abfall transfertauglicher Rinderembryonen auf 9,2% (2,6–16,9%) nach sich. In einer Kurzzeitkultivierung von bis zu 90 h post inseminationem wurden außerdem verschiedene Serumanaloga, im Anteil von 10%, wie fetales Kälberserum (FKS), ÖFF und Follikelflüssigkeit (NÖFF) aus nicht östrischen Follikeln (≥ 10mm Durchmesser) auf ihre Wirksamkeit während verschiedener In-vitro-Phasen verglichen. Von den drei getesteten Seren erwies sich die ÖFF als der wirksamste Zusatz mit 19,9% morphologisch intakten 8- bis 16-Zeller. Das Ergebnis scheint unabhängig davon, ob die Applikation kontinuierlich während aller In-vitro-Phasen oder nur in der Reifungsphase erfolgte. Eine Schlüsselposition der Oozy tenreifung für die In-vitro-Fertilisation wird besonders deutlich. Contents: Influence of follicular fluid on fertilization of in vitro matured bovine oocytes Follicular fluid obtained from bovine follicles on the day of estrus was added to TCM 199 culture medium as a serum analogue. TCM supplementation with 20% estric follicular fluid (EFF) during maturation and zygote cultivation produced a morulae and blastozyst yield of 41,7% (30,8–47,8%) 6–7 days after insemination. Reduction of the EFF fraction to 10% reduced the yield of transferable bovine embryos to 9,2% (2,6–16,9%). In a short term cultivation experiment lasting up to 90 h after insemination, the effects of 10% supplementation with different serum analogues fetal calf serum (FCS), EFF and follicular fluid (NEFF) fiom non-estric follicles (≥10mm diameter) during various in vitro phases were compared. EFF with a yield of 19,9% morphologically intact 8 to 16 cell stages proved to be the most effective of the three sera. This yield is not apparently affected by whether the serum is applied continuously during all phases of in vitro development or only during the maturation phase. The oocyte maturation phase is obviously the key phase for successful in vitro fertilization. 相似文献
69.
Ayllón D, Almodóvar A, Nicola GG, Elvira B. Ontogenetic and spatial variations in brown trout habitat selection.Ecology of Freshwater Fish 2010: 19: 420–432. © 2010 John Wiley & Sons A/S Abstract – Habitat quality and quantity determine many biological processes and traits that directly affect the population dynamics of stream fishes. Understanding how habitat selection is adjusted to different ecological conditions is essential to improve predictive modelling of population dynamics. We describe brown trout Salmo trutta summer habitat selection patterns through univariate and multivariate habitat selection functions across defined river reach typologies. We sampled 44 sites and performed a principal component analysis that defined eight reach types differing in both local site and catchment‐scale physical features. We observed ontogenetic changes in habitat selection, as trout preferred deeper and slower flowing water as they increased in size. Likewise, selectivity for different types of structural habitat elements changed through ontogeny. Both patterns were consistent across reach types. Moreover, we detected spatial variations in habitat selection patterns within age‐classes among different reach types. Our results indicate that brown trout is a habitat generalist and suggest that spatial variations in habitat selection patterns are driven by physical and environmental factors operating at multiple spatial scales. 相似文献
70.
Catalytic inhibition of human DNA topoisomerase II by interactions of grape cell culture polyphenols
Previously, we isolated mixed polyphenolic fractions on a toyopearl matrix (TP-2 to TP-6) from grape cell cultures that were highly potent catalytic inhibitors in a human DNA topoisomerase II assay for cancer chemoprevention. The objectives of this study were to evaluate the potency of, and potential interactions between, individual fractions and some of the purified bioactive polyphenols that comprise these fractions on human DNA topoisomerase II catalytic activity. Treatments that combined anthocyanin-rich fractions (TP-2; 0.5 or 2.0 microg of dried material/mL), fractions containing catechins, procyanidin dimers, and flavanones (TP-4; 0.25 microg of dried material/mL), and/or fractions enriched with procyanidin oligomers and polymers (TP-6; 0.15 or 0.5 microg of dried material/mL) showed additive effects toward catalytic inhibition of the enzyme. Epicatechin gallate (IC50 = 0.029 microM), myricetin (0.39 microM), procyanidin B2 (PB2, 4.5 microM), and resveratrol (65.7 microM), constituents of the most bioactive mixed fraction from grape cell culture (TP-4), each individually provided potent catalytic inhibition of topoisomerase II. In addition, potentiating interactions between the PB2 and the other polyphenolic constituents mentioned above and between myricetin and resveratrol were clearly demonstrated. A synergistic interaction between myricetin and resveratrol was also confirmed with isobolographic analysis at a molar ratio of 1:70. 相似文献