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41.
Sverre Ola Roald 《Aquaculture (Amsterdam, Netherlands)》1977,12(4):327-335
Young rainbow trout (Salmo gairdneri) were exposed to lignosulphonates (LS) at concentrations of 0, 40, 80, 160, 320, 640, 1 280 and 1 920 ppm for 35 or 60 days. At concentrations of 160 ppm LS and higher the growth rates were slower. The higher concentrations had the most retarding effect on growth, but a clear general relationship between LS concentration and growth retardation was not observed.The bacterial flora in the digestive tract of the fish was examined. The predominant micro-organisms were flavobacteria, bacilli, streptococci and yeasts (Cryptococcus spp.), which were also isolated from the diet. There were about 10 000 viable aerobic and 1 000 anaerobic bacteria per gramme of intestinal contents. There was no significant difference in quantitative or qualitative composition of the intestinal flora of the different groups.The following groups of digestive enzymes were studied: proteinases, amylases, lipases and deoxyribonucleases. The activities of proteinases and nucleases were significantly impaired in fish exposed to concentrations of 1 280 ppm LS and higher, and those of amylases at concentrations of 320 ppm LS and higher. A possible connection between the reduced growth rates and depressed activities of the digestive enzymes is discussed, but no firm conclusion regarding the mechanism by which LS effects fish growth can be made on the basis of the present study. 相似文献
42.
Seblewengel B. Talle Erling Fimland Ola Syrstad Theo Meuwissen Helge Klungland 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(2-3):74-79
Abstract Comparisons of seven different individual assignment methods based on likelihood and distances were carried out with four different sets of data, which varied both in number of populations and genetic divergence. Based on 27 microsatellites genotyped in eight cattle breeds (Icelandic and seven Norwegian), 28 hybrid populations were simulated. Factors affecting individual assignment success, such as number and divergence of populations, sample size and number of loci, were assessed from actual and simulated data. The Bayesian, frequency and Nei-minimum methods performed more or less similarly. Individual assignment success depended mainly on population number and divergence (FST). Higher success was observed at high level of divergence among populations and at low number of source populations considered. With eight pure breeds and 27 loci considered the assignment success rate ranged from 55 to 70%. Generally, assignment success increased with increasing number of loci and/or sample size. 相似文献
43.
Anu Korosuo Hampus Holmström Karin öhman Ljusk Ola Eriksson 《European Journal of Forest Research》2013,132(3):551-563
Decision making in forest planning often involves situations, where the value of the stand is dependent on its location or the properties of the stands nearby. Often the most intuitive tool to describe spatial objectives and outcomes is a visual map. However, evaluating and comparing different maps may prove a considerable cognitive burden, especially over large areas and in long-term planning. In this study, we investigate the use of value functions for eliciting spatial preference information from maps. Our case study is part of a project investigating the possibilities of increasing broadleaf-tree-dominated habitats in a northern Swedish landscape. The experts involved in the project evaluated maps showing different fragmentation patterns. Different spatial indices were then calculated for the maps, and expert evaluations were used to sketch value functions describing the preferred fragmentation level. The approach was found to be a quick way of translating spatial preferences into numerical values and conceptualizing the relatively abstract concept of fragmentation in the landscape. Furthermore, the results show that the choice of a certain fragmentation index has a crucial effect on the value function. 相似文献
44.
Hwaida Jaber Elias Baydoun Ola EL-Zein Sawsan Ibrahim Kreydiyyeh 《Plant foods for human nutrition (Dordrecht, Netherlands)》2013,68(1):83-89
Water extract of banana (Musa sapientum) infructescence stalks has been used in folk medicine in the treatment of diabetes mellitus. This work aims at verifying the claimed effect and elucidating its possible mode of action. The extract was given in replacement of drinking water to diabetic rats, and its mechanism of action was studied by investigating its involvement in glucose transport in Caco-2 monolayers, and in rat jejuna using an in situ perfusion technique. Its effect on the Na+/K+ ATPase was studied by measuring the amount of inorganic phosphate liberated. The extract reduced significantly blood glucose levels in diabetic rats and glucose transport across rat jejuna and Caco-2 monolayers, and induced a 50 % decrease in their Na+/K+ ATPase activity. The extract did not induce any further decrease in jejunal glucose uptake in the simultaneous presence of phloridzin and phloretin, respective inhibitors of SGLT1 and GLUT2 transporters nor did it induce a change in the protein expression of SGLT1 and GLUT2. It was concluded that the extract acts by reducing the Na+/K+ ATPase activity of enterocytes and consequently the sodium gradient required for sugar transport by SGLT1, which leads to down-regulation of GLUT2 and contributes to the observed anti-hyperglycemic effect. 相似文献
45.
46.
Ola Tveitereid Westengen Progress Nyanga Douty Chibamba Monica Guillen-Royo Dan Banik 《Agriculture and Human Values》2018,35(1):255-268
The promotion of conservation agriculture (CA) for smallholders in sub-Saharan Africa is subject to ongoing scholarly and public debate regarding the evidence-base and the agenda-setting power of involved stakeholders. We undertake a political analysis of CA in Zambia that combines a qualitative case study of a flagship CA initiative with a quantitative analysis of a nationally representative dataset on agricultural practices. This analysis moves from an investigation of the knowledge politics to a study of how the political agendas of the actors involved are shaping agrarian practices. From its initial focus on CA as soil conservation and sustainable agriculture, the framing of the initiative has evolved to accommodate shifting trends in the policy arena. In tandem with the increased focus on climate adaptation, we see an increased emphasis on private sector-led modernisation. The initiative has shifted its target group from the poorest smallholders to prospective commercial farmers, and has forged connections between its farmer-to-farmer extension network and private input suppliers and service providers. The link between CA and input intensification is reflected in national statistics as a significantly higher usage of herbicides, pesticides and mineral fertilizer on fields under CA tillage compared to other fields. We argue that the environmental and participation agendas are used to buttress CA as an environmentally and socially sustainable agricultural development strategy, while the prevailing practice is the result of a common vision for a private sector-led agricultural development shared between the implementing organisation, the donor and international organisations promoting a new green revolution in Africa. 相似文献
47.
Integrated approaches to forest planning lead to large models and there is a subsequent need for a reduction of the number of constraints and variables. One way of achieving this is to aggregate data, either spatially or temporally. In this paper an integrated forest planning mixed integer model that takes into account both long-term strategic and shorter-term tactical forest management decisions is utilised. The study analyses the consequences of temporal aggregation in the strategic part of the integrated model, whereas the tactical part is modelled by a fixed set of years divided into seasons. For reference, analyses are also made using a pure strategic linear programming model. Cases using both equal and variable strategic period lengths are presented, and two case study areas are used. Results indicate that integrated plans, as well as strategic plans, are not particularly affected by the number of equal length strategic periods when more than five periods, i.e. less than 20 year period length, are used. When modelling strategic and integrated problems using variable-length periods, care should be taken to ensure that harvest operations late in the planning horizon get enough timing options to be adequately described. 相似文献
48.
Zaki Zaki Sharawy Mohamed Ashour Eman Abbas Ola Ashry Mohamed Helal Hany Nazmi Mahmoud Kelany Abdelwahab Kamel Mohamed Hassaan Waldemar Rossi Ehab El‐Haroun Ashraf Goda 《Aquaculture Research》2020,51(6):2216-2228
The marine flagellated Chlorophyta Tetraselmis suecica is among the most important live food species in marine aquaculture. In the present study, the effects of dietary supplementation of dried marine microalgae, Tetraselmis suecica, on growth performance; feed utilization; chemical composition; gene expression of superoxide dismutase (SOD), glutathione peroxidase (GPx) and insulin‐like growth factor 2 (IGF‐II) gene of Pacific white shrimp, Litopenaeus vannamei; muscle protein polymorphism; and microbial count were assessed and evaluated. Three hundred and sixty L. vannamei (postlarvae) Pls (0.124 ± 0.002 g) were randomly stocked into 40‐L glass aquaria (30 shrimp/aquarium) and fed three times daily four tested diets: a basal diet (control), diet incorporated with 2.5 g kg?1 dried T. suecica (T1), 5 g kg?1 dried T. suecica (T2) and 7.5 g kg?1 dried T. suecica (T3) in triplicates, for 90 days. At the end of the trial, the survival rate (SR) of L. vannamei fed diets supplemented with different levels of T. suecica was significantly (p < .05) higher than the control diet. The highest weight gain and specific growth rate and the best feed conversion ratio were recorded on L. vannamei fed a diet supplemented with a 7.5 g/kg dried T. suecica. The highest protein, lipid and ash contents were obtained in L. vannamei fed the diet containing 7.5 g/kg T. suecica, when compared with the remaining tested diets. The gene expression of antioxidant genes SOD and GPx was the lowest in the T3 group in comparison with the control group. Meanwhile, expression level of IGF‐II was higher in the T2 group. The total heterotrophic bacterial count was significantly (p < .05) increased with the cumulative T. suecica level, while no significant (p > .05) differences were found in the total Vibrio count among treatments. Overall, the present results have shown that the diet supplemented with the highest inclusion level of dried T. suecica resulted in improved growth and nutrient utilization. 相似文献
49.
Robert J. Lennox Henrik H. Berntsen Åse Helen Garseth Scott G. Hinch Kjetil Hindar Ola Ugedal Kjell R. Utne Knut Wiik Vollset Frederick G. Whoriskey Eva B. Thorstad 《Fish and Fisheries》2023,24(5):759-776
While populations of other migratory salmonids suffer in the Anthropocene, pink salmon (Oncorhynchus gorbusca Salmonidae) are thriving, and their distribution is expanding both within their natural range and in the Atlantic and Arctic following introduction of the species to the White Sea in the 1950s. Pink salmon are now rapidly spreading in Europe and even across the ocean to North America. Large numbers of pink salmon breed in Norwegian rivers and small numbers of individuals have been captured throughout the North Atlantic since 2017. Although little is known about the biology and ecology of the pink salmon in its novel distribution, the impacts of the species' introduction are potentially highly significant for native species and watershed productivity. Contrasts between pink salmon in the native and extended ranges will be key to navigating management strategies for Atlantic nations where the pink salmon is entrenching itself among the fish fauna, posing potential threats to native fish communities. One key conclusion of this paper is that the species' heritable traits are rapidly selected and drive local adaptation and evolution. Within the Atlantic region, this may facilitate further establishment and spread. The invasion of pink salmon in the Atlantic basin is ultimately a massive ecological experiment and one of the first examples of a major faunal change in the North Atlantic Ocean that is already undergoing rapid changes due to other anthropogenic stressors. New research is urgently needed to understand the role and potential future impacts of pink salmon in Atlantic ecosystems. 相似文献
50.
Hildreth BE Marcellin-Little DJ Roe SC Harrysson OL 《American journal of veterinary research》2006,67(4):693-700
OBJECTIVE: To compare application time, accuracy of tibial plateau slope (TPS) correction, presence and magnitude of rotational and angular deformities, and mechanical properties of 5 canine tibial plateau leveling methods. SAMPLE POPULATION: 27 canine tibial replicas created by rapid prototyping methods. PROCEDURE: The application time, accuracy of TPS correction, presence and magnitude of rotational and angular deformation, and construct axial stiffness of 3 internal fixation methods (tibial plateau leveling osteotomy, tibial wedge osteotomy, and chevron wedge osteotomy [CWO]) and 2 external skeletal fixation (ESF) methods (hinged hybrid circular external fixation and wedge osteotomy linear fixation [WOLF]) were assessed. RESULTS: Mean bone model axial stiffness did not differ among methods. Mean application time was more rapid for WOLF than for other methods. Mean TPSs did not differ from our 5 degrees target and were lower for ESF methods, compared with internal fixation methods. Mean postoperative rotational malalignment did not differ from our target or among groups. Mean postoperative medio-lateral angulation did not differ from our target, except for CWO. Internal fixation methods lead to axially stiffer constructs than ESF methods. Reuse of ESF frames did not lead to a decrease in axial stiffness. CONCLUSIONS AND CLINICAL RELEVANCE: The 5 tibial plateau leveling methods had acceptable geometric and mechanical properties. External skeletal fixation methods were more accurate as a result of precise data available for determining the exact magnitude of correction required to achieve a 5 degrees TPS. 相似文献