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Market-based fisheries management systems give incentives to reduce the fleet size and employment, which increases earnings and contributes to resolve the tragedy of the commons. However, the often-stated expectation that economies of scale cause the disappearance of small-scale fishery is not observed in many cases. In this study, we investigate the effects on fleet structure in the period after introducing individual fishing quotas or individual fishing days with various degrees of transferability in selected fisheries in the seven Nordic countries. Despite observing economies of scale in most cases, it is found that the market-based fisheries management often does not reduce the small-scale fleet more than the fleet of large vessels. This is explained partly by small vessels targeting demersal species and large vessels pelagic species, and partly by the larger need of larger than small vessels to continuously utilize their capital stocks through fast adaptation to ensure return. A more important explanation is the regulation design, with limitations in sale of fishing rights and lease between vessel groups and regions and in the share of the total quota holdings of fishing rights by individuals and vessels. This is important for countries considering the introduction of market-based fisheries management, since the Nordic experiences show that with proper regulation design, economic gains can be achieved with small-scale fishing surviving even under economies of scale.  相似文献   
33.
Damage caused by pine weevil (Hylobius abietus L.) to planted seedlings and cuttings of Norway spruce (Picea abies (L.) Karst.) was studied at five clearcut sites in south-eastern Sweden. The main objective was to compare the two types of stock in terms of attack frequency and mortality due to pine weevil feeding. Cuttings and seedlings with the same initial stem-base diameter (4 mm) were compared. Two sites were harvested and scarified shortly before planting, two were harvested shortly before planting, but were not scarified, and one was harvested 2 years before and scarified the autumn before planting. The total mortality 5 years after planting was highest, greater than 90%, at the new, non-scarified sites, and lowest, 23%, at the old, scarified site. More than 90% of the mortality was caused by pine weevil feeding. Attack frequency and pine weevil induced mortality were significantly higher among seedlings than among cuttings. Mortality due to pine weevil damage was 4–43% higher in seedlings than in cuttings after the fifth year. Of the cuttings and seedlings that were attacked in the first year, a significantly higher frequency of the seedlings were girdled. The higher resistance of cuttings to pine weevil damage may partly explain the more rapid growth of cuttings reported in other studies. However, the causes of their higher resistance need to be further investigated. The thicker bark and needles on the stem base of the cuttings could be important in this respect.  相似文献   
34.
Eriksson  Erik; Berg  Staffan 《Forestry》2007,80(2):99-111
Forestry has an important role to play as a provider of energyfrom renewable biomass and through the sequestration of carbonin biomass and soil. Forests are also habitats for a large numberof species which are important for biodiversity. In some cases,these two roles may conflict. The aim of this study was to modelthe implications of specific environmental quality objectiveson the potential of forestry to reduce net CO2 emissions byaddressing interim targets 1 and 2 in the environmental qualityobjective, sustainable forests for Uppsala County and used thisregion as a case study. The carbon stock in the biomass, thesubstitution effect, and the economic consequences associatedwith six forest management scenarios were considered. The developmentfor the scenarios was simulated at stand level using an empiricalmodel. The results of the study showed that the shortest rotationperiod was preferable to mitigate net CO2 emissions since itresulted in more biomass that could replace fossil fuel. However,such a strategy might affect sustainable policies negatively.Increasing the extent of mixed stands could be a preferablestrategy since it may achieve several objectives.  相似文献   
35.
In Fennoscandia, logging residues (LR) are increasingly being harvested to provide fuel for renewable energy. However, the removal of LR is thought to lead to decreased growth in the next generation of trees. The effect on tree growth has generally been obtained by comparing the total removal of residues with retained residues spread evenly on the ground. With current clear-cutting practices, residues can be left with different spatial distributions, confounding the effects of residue removal. Field experiments were, therefore, established at two Norway spruce sites, comprising six treatments with varying distributions and volumes of residues. Before planting seedlings, the sites were disc-trenched. At one of the sites, seedling survival was significantly lower when all residues were removed immediately. At both sites, after 10 years there were statistically significant growth losses after removal of residues. There were no differences in plant growth if the residues were concentrated in small heaps and strings, simulating the normal distribution of LR following stem-only harvesting, compared with residues left evenly spread on the ground. To determine the duration of the observed growth effects, these study sites must be monitored more long term.  相似文献   
36.
Serum thymidine kinase (sTK) activity was evaluated as a tumor marker for canine malignant lymphoma (ML). The objective was to investigate if sTK, as in humans, could be used as a prognostic marker for survival time in dogs with ML and if sTK could identify early signs of progression of disease in treated dogs. Serum samples from 52 dogs with ML were tested for initial TK activity. Samples from 21 normal dogs and 25 dogs with nonhematologic neoplasms were used for comparison. Forty-four dogs with ML were treated. Serum TK activity was measured in treated dogs before each treatment and every 4 weeks thereafter until relapse. Dogs with ML had 2-180 times higher TK activity (TK 5-900 U/L) than normal dogs (TK <7 U/L) based on the mean + 2 standard deviations. In the group of other neoplasms, only 2 dogs had a moderate increase (6.4 and 7.5 U/L) compared with the controls. Mean sTK activities in the dogs with ML that had gone into complete remission (CR) were not significantly different from activities in healthy controls (P = .68). Mean sTK at least 3 weeks before and at the time of relapse was significantly higher than activity measured at CR (P < .0001). Dogs with ML that initially had sTK >30 U/L had significantly shorter survival times (P < .0001). Furthermore, sTK activity reflected the clinical staging of ML. Measuring sTK can be used as a powerful objective tumor marker for prognosis and for predicting relapse before recurrence of clinically detectable disease in dogs with ML undergoing chemotherapy.  相似文献   
37.
Sea buckthorn berries ( Hippophae rhamnoides L.) are used in foods, cosmetics, and pharmaceutical products. They are of particular interest for their high content of healthy phytochemicals, including vitamin E-related compounds (tocopherols and tocotrienols). This study investigated the content of tocopherols and tocotrienols during ripening in berries from four cultivars of sea buckthorn over a three-year period. The results showed large variations in tocopherols and tocotrienols depending on harvest date, cultivar, and year. Levels of alpha-tocopherol were higher early in the ripening period, while at later dates, delta-tocopherol levels increased. Great differences in amounts and composition of tocopherols and tocotrienols were observed between cultivars. Tocopherol levels were positively correlated with daily temperature, but this trend varied between years. Variations in tocopherols and tocotrienol levels in sea buckthorn berries due to cultivar, year, and ripening stage should therefore be considered in the production of nutritional products.  相似文献   
38.
In this article, the development and operationalisation of forestry-wood chain indicators within the frame of sustainability impact assessment are discussed. The analytical framework follows a distinction between indicator definition and selection in a first phase, and a second operational phase of indicator application in terms of interconnecting material flows, calculation of chain performance and utilisation within evaluation components. A clear boundary drawing effort in terms of the development of indicator definitions, related subclasses, and measurement units as well as the creation of conversion factors between indicator values and individual chain stages supports this. Economic, social and environmental indicators have to respond to data collection needs on individual process levels (that correspond to sub-divisions of the forestry-wood chain). For the usage of indicators within evaluation tools, a functional hierarchy has to be provided that supports clear preference elicitation as well as information on related externalities. In total, this paper aims at demonstrating an enhanced spectrum in the use of sustainability indicators, and the challenges that arise from a developing and applying multi-functional indicators in sustainability impact assessment.  相似文献   
39.
The purpose of this study was to evaluate the efficacy of high molecular weight (HMW) sodium hyaluronate (Hylartin V) for treatment of acute equine superficial flexor tendinitis. The study was a blinded randomized clinical study with placebo control. The horses included in the study were clinical patients diagnosed with tendinitis based on physical symptoms and ultrasonography, as well as historical information consistent with acute onset. Sixty-three horses were enrolled in the study, but ten were excluded from statistical analysis because they had tendon injuries in more than one leg (seven cases, four horses) or in a hind leg (three cases, three horses).Two (2) ml of sodium hyaluronate (treatment group) or 2 ml of saline (placebo) was given as a single injection into the center of the superficial flexor tendon lesion. All other treatments and exercise recommendations were the same in both groups. The end point of the study was resolution of the ultrasonographic lesion within a six-month period. The results showed that 60% of the horses in the Hylartin V treatment group had their lesions resolved in that time frame, while 24% of the placebo group showed a similar degree of improvement and resolution. It was concluded that the treatment with HMW sodium hyaluronate significantly improves the rate of ultrasonographic resolution as compared with placebo control.  相似文献   
40.
The forest sector is important for the German Federal State of Baden-Württemberg (BW) and the Västerbotten (VB) County in Sweden. Their forestry wood chains (FWCs) are of similar magnitude and supply forest industries. This study provides a regional comparison of the performance of FWCs from roundwood harvesting, including hauling, to mill gate concerning the factors that impact sustainability and assess different sustainability indicators for alternative supply chains, in particular fully mechanized chains in comparison to motor-manual operations. The harvest volumes are similar but operational conditions differ. Analysis of sustainability indicators demonstrated that the total costs for roundwood to industry are similar. Higher harvesting costs in BW are compensated for by lower transport costs to the mills. Employment per unit is higher in BW because of the high share of labour in felling. Due to smaller machinery and shorter transport distances in BW, energy use and greenhouse gas emissions per unit are lower than in VB. Areas for improvement are the technologies for logging in BW and the logistics of timber transport in VB.  相似文献   
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