全文获取类型
收费全文 | 231篇 |
免费 | 13篇 |
专业分类
林业 | 14篇 |
农学 | 4篇 |
基础科学 | 1篇 |
35篇 | |
综合类 | 20篇 |
农作物 | 18篇 |
水产渔业 | 16篇 |
畜牧兽医 | 117篇 |
园艺 | 5篇 |
植物保护 | 14篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 5篇 |
2014年 | 7篇 |
2013年 | 10篇 |
2012年 | 12篇 |
2011年 | 14篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 20篇 |
2007年 | 16篇 |
2006年 | 8篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 15篇 |
2002年 | 12篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 4篇 |
排序方式: 共有244条查询结果,搜索用时 797 毫秒
81.
Siano Francesco Cutignano Adele Moccia Stefania Russo Gian Luigi Volpe Maria Grazia Picariello Gianluca 《Plant foods for human nutrition (Dordrecht, Netherlands)》2020,75(4):487-494
Plant Foods for Human Nutrition - The ethno-pharmaceutical use of the edible fixed oil produced from lentisk (Pistacia lentiscus) berries covers a long tradition in several Mediterranean regions.... 相似文献
82.
Toiber-Yasur Inbar Rosner M. Hadas Aviva Russo D. Yaron B. 《Water, air, and soil pollution》1999,113(1-4):319-335
A field experiment was designed to provide data on the effect of soil heterogeneity on the distribution of herbicides following leaching by irrigation and rain water. Terbuthylazine and bromacil, two nonconservative herbicides, together with CaBr2, a conservative chemical, were used in the reported experiment. The experimental field consisted of a noncultivated 175-m2 plot in which 20 observation points were randomly selected. A hundred and ten centimeters of irrigation and rainwater were applied and the field was periodically sampled for chemical distributions. The spatial variability of the field was determined by measuring the Ks (saturated conductivity) and α (Gardner parameter). Auxiliary laboratory experiments were performed to define the adsorption-desorption of the chemicals studied in these field soils. Results on the adsorption-desorption of terbuthylazine and bromacil and on the redistribution of these chemicals in the field to a depth of 120 cm during leaching are shown. Bromacil leached to a greater extent than terbuthylazine. The differences among the concentrations of herbicides in the various cores studied may be explained in terms of properties of the chemicals and soil spatial variability. The residual concentrations of terbuthylazine and bromacil were also determined to a depth of 400 cm after the leaching of 110 cm of water. In some of the cores, two zones showing a relatively high concentration of terbuthylazine and bromacil were observed at depths of 40–60 and 200–300 cm, respectively. This redistribution pattern of the herbicides could be explained by the preferential flow of the solute in the cores studied. 相似文献
83.
Victor S Panangala Riccardo Russo Vicky L van Santen Karen G Wolfe & Phillip H Klesius 《Aquaculture Research》2009,40(10):1135-1147
Edwardsiella ictaluri , the cause of enteric septicaemia in channel catfish ( Ictalurus punctatus ), is motile by means of peritrichous flagella. We determined the complete flagellin gene sequences and their organization in E. ictaluri by sequencing genomic segments from a λ-ZAP phage genomic library of E. ictaluri . Four flagellin genes ( fliC1, fliC2, fliC3 and fliC4 ) are arranged in tandem within 6 kb in the E. ictaluri genome. Each flagellin-coding sequence is preceded by a σ28 recognition site consensus sequence. The predicted amino acid sequences of all four flagellin proteins (between 36 and 37.5 kDa) are similar in the N-terminal (1–160 aa) and C-terminal (last 74 aa) portions and are divergent in the central portion of the proteins. Proteins encoded by flC1, fliC2 and fliC3 are more similar to each other (88–90% aa identity) than to the protein encoded by fliC4 (76–78% aa identity). basic local alignment search tool analysis of GenBank sequences showed that all flagellin aa sequences are more similar to those of Serratia marcescens (72–74% identity) than to those of Edwardsiella tarda (≤64% identity). Primary determination of E. ictaluri flagellin gene sequences facilitate advanced studies on the role of flagella in host–pathogen interaction. 相似文献
84.
Victor S Panangala Craig A Shoemaker Phillip H Klesius Amitava Mitra & Riccardo Russo 《Aquaculture Research》2009,40(8):915-926
Cross-protection of channel catfish ( Ictalurus punctatus Rafinesque) immunized with a low dose of virulent Edwardsiella ictaluri and challenged with six E. ictaluri strains was examined in four trials. The relative per cent survival among low-dose immunized and then challenged fish ranged from 27.7% to 100%. Significant protection ( P <0.05), with the exception of strain ATCC-33202, was conferred by immunization with a given E. ictaluri strain challenged either with a homologous or a heterologous strain. Antibody titres of pooled serum collected on day 22 from surviving fish examined by enzyme-linked immunosorbent assay (ELISA) ranged from 1:40 to 1:320, but no differences were apparent among different vaccinated groups. The protein profiles of six E. ictaluri strains examined by Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed a relatively homogeneous pattern. Immuno-blots probed with pooled serum from immunized and challenged fish showed a pattern similar to LPS-reaction patterns observed with E. ictaluri in other studies. Since the present studies further corroborate that E. ictaluri is a clonal bacterial species with no apparent antigenic differences, it is possible that immunization with a single E. ictaluri field strain should confer protection against any other strain. 相似文献
85.
86.
Modelling the impact of agricultural abandonment and wildfires on vertebrate diversity in Mediterranean Europe 总被引:1,自引:0,他引:1
Agricultural land abandonment, widespread in the Mediterranean, is leading to a recovery of scrubland and forests which are
replacing open habitats and increasing wildfire events. Using published data, we modelled the global and regional impact of
abandonment and wildfires on 554 species of terrestrial vertebrates occurring in Mediterranean Europe. For all groups except
amphibians, open habitats or farmland sustained higher species richness. Open habitats showed regional differences in their
conservation value, western areas being particularly important for birds and amphibians and eastern areas for reptiles. Scrublands
hosted fewer species than open habitats, farmland and forest, but sustained several endemic birds and mammals. The greater
species richness of forests was mostly due to species widespread in Europe. Wildfires promote scrubland expansion in detriment
of forest; because more species are associated to eastern forests, fire is predicted to affect more seriously this region.
Scrubland conservation value was found to be highest in the west, where fire might have a positive impact. Fire regime, however,
plays a crucial role. Although large fires have a negative impact, small-scale fires may favour biodiversity in abandoned
areas. Due to the intrinsic difficulty in managing abandoned land to preserve the original Mediterranean vertebrate diversity,
the best option to achieve this goal is the development of policies designed to make farmers and traditional farmland survive. 相似文献
87.
Virus isolation from saliva and salivary glands of cattle naturally infected with paralytic rabies 总被引:1,自引:0,他引:1
The infectivity of saliva, salivary and mammary glands, muscle, lung, kidney and liver of 87 cattle infected with paralytic rabies (positive viral isolation from brains) was studied. Fifty percent dilutions of saliva and tissue samples were inoculated intracerebrally into 10- to 15-day-old mice. Viral isolation in mice was confirmed by direct rabies fluorescent-antibody test and the antigenic variant of the isolates characterized by monoclonal antibodies. Rabies virus was isolated from 4.6% of salivary glands and from 1.6% of saliva samples. The rest of the peripheral tissues were negative. Cerebral and peripheral isolates belonged to vampire-bat antigenic variants. These results indicate that cattle infected by vampire bats may be a source of infection for man. The infection risk would depend on the type of contact between rabid cattle and man. 相似文献
88.
Shear-wave splitting of S and SKS phases reveals the anisotropy and strain field of the mantle beneath the subducting Nazca plate, Cocos plate, and the Caribbean region. These observations can be used to test models of mantle flow. Two-dimensional entrained mantle flow beneath the subducting Nazca slab is not consistent with the data. Rather, there is evidence for horizontal trench-parallel flow in the mantle beneath the Nazca plate along much of the Andean subduction zone. Trench-parallel flow is attributale utable to retrograde motion of the slab, the decoupling of the slab and underlying mantle, and a partial barrier to flow at depth, resulting in lateral mantle flow beneath the slab. Such flow facilitates the transfer of material from the shrinking mantle reservoir beneath the Pacific basin to the growing mantle reservoir beneath the Atlantic basin. Trenchparallel flow may explain the eastward motions of the Caribbean and Scotia sea plates, the anomalously shallow bathymetry of the eastern Nazca plate, the long-wavelength geoid high over western South America, and it may contribute to the high elevation and intense deformation of the central Andes. 相似文献
89.
This paper investigates how Food Security (FS) is enacted in a southern region of Italy, characterized by high rates of mafias-related activity, arguing for the inclusion in the research of socio-cultural features and power relationships to explain how Alternative Food Networks (AFNs) can facilitate individual empowerment and community resilience. In fact, while FS entails legality and social justice, AFNs are intended as ‘instrumental value’ to reach the ‘terminal value’ of FS within an urban community in Sicily, as well as the space where citizens can act their individual and collective political food choices. Building on the social psychology literature and on ecologic-psychopolitical models (Christens and Perkins in J Commun Psychol 36(2):214–231, 2008), we discuss the case of Addiopizzo, a citizen project promoting the legality of their AFNs through the rejection of the payment of the pizzo (the protection money asked by racket) in the local food chain. The aim is to problematize the extent to which FS is able to re-localize ‘legal’ food in the market. This was done by reconnecting citizens to their space and territory in a socio-cultural context at risk where agro-food producers, retailers and consumers are not free to fully enact their citizenship agency because of a widespread illegal structure. The research findings show that Addiopizzo project enables citizens to act their social power: agro-food producers and retailers by subscribing to formal requirements based on values that reject racket; consumers by purchasing Addiopizzo labelled products; individuals and groups by participating further open-to-the-public activities that promote everyday politically oriented behaviour. The citizen empowerment and community resilience can be exerted within AFNs as they are interconnected paths of reflexivity and social learning within social adaptation. The paper concludes by advocating the role of urban communities as a pivotal agent to maintain positive social adaptations, where AFNs work as a socio-cultural synthesis of traditional and alternative producer–consumer ways of interaction, which are embodied in the FS value. 相似文献
90.
Mumma MJ DiSanti MA Magee-Sauer K Bonev BP Villanueva GL Kawakita H Dello Russo N Gibb EL Blake GA Lyke JE Campbell RD Aycock J Conrad A Hill GM 《Science (New York, N.Y.)》2005,310(5746):270-274
We quantified eight parent volatiles (H2O, C2H6, HCN, CO, CH3OH, H2CO, C2H2, and CH4) in the Jupiter-family comet Tempel 1 using high-dispersion infrared spectroscopy in the wavelength range 2.8 to 5.0 micrometers. The abundance ratio for ethane was significantly higher after impact, whereas those for methanol and hydrogen cyanide were unchanged. The abundance ratios in the ejecta are similar to those for most Oort cloud comets, but methanol and acetylene are lower in Tempel 1 by a factor of about 2. These results suggest that the volatile ices in Tempel 1 and in most Oort cloud comets originated in a common region of the protoplanetary disk. 相似文献