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11.
12.
The treatability of Scots pine sapwood sampled from 25 locations in northern Europe, which was impregnated with an experimental furfuryl alcohol mix, was studied. A large variation in treatability was found between stands. The treatability was affected by anatomical properties of the trees and therefore also by the immediate climate, the sociological position of the tree in the stand, growth increments and on-stand competition. With the models applied, most parts of the differences in treatability between stands could be explained, while the treatability variation between trees within a stand remained mostly unexplained. Wider annual rings and higher latewood contents were found to increase the treatability. Models that included data on growth conditions and climate explain more of the variation in treatability, indicating that also other anatomical properties are influencing the treatability. Tree attributes and growth conditions that reduce annual ring width and latewood content decreased the treatability. Trees growing under warmer conditions and developing larger growth increments were easier to impregnate. Wood from trees growing near the timberline and under environmental conditions impairing wood growth was more difficult to treat.  相似文献   
13.
The paper reviews recent progress in larviculture of Atlantic cod and Atlantic halibut in different experimental enclosed seawater systems in Norway. More than 240,000 cod juveniles have been produced in a 270,000 m3 seawater pond. However, very promising production results of cod have been achieved in plastic enclosures with volumes > 100 m3. Halibut juveniles have been successfully produced in plastic enclosures and tanks by using natural zooplankton as food. The enclosure technique could be adapted to commercial scale production of juvenile halibut. However, scaling up experiments are necessary.  相似文献   
14.
Samples (blood or tissue fluid) from 594 arctic foxes (Alopex lagopus), 390 Svalbard reindeer (Rangifer tarandus platyrhynchus), 361 sibling voles (Microtus rossiaemeridionalis), 17 walruses (Odobenus rosmarus), 149 barnacle geese (Branta leucopsis), 58 kittiwakes (Rissa tridactyla), and 27 glaucous gulls (Larus hyperboreus) from Svalbard and nearby waters were assayed for antibodies against Toxoplasma gondii using a direct agglutination test. The proportion of seropositive animals was 43% in arctic foxes, 7% in barnacle geese, and 6% (1 of 17) in walruses. There were no seropositive Svalbard reindeer, sibling voles, glaucous gulls, or kittiwakes. The prevalence in the arctic fox was relatively high compared to previous reports from canid populations. There are no wild felids in Svalbard and domestic cats are prohibited, and the absence of antibodies against T. gondii among the herbivorous Svalbard reindeer and voles indicates that transmission of the parasite by oocysts is not likely to be an important mechanism in the Svalbard ecosystem. Our results suggest that migratory birds, such as the barnacle goose, may be the most important vectors bringing the parasite to Svalbard. In addition to transmission through infected prey and carrion, the age-seroprevalence profile in the fox population suggests that their infection levels are enhanced by vertical transmission.  相似文献   
15.
The pigmentation and corresponding in vivo and in vitro absorption characteristics in three different deep-water coral species: white and orange Lophelia pertusa, Paragorgia arborea and Primnoa resedaeformis, collected from the Trondheimsfjord are described. Pigments were isolated and characterized by High-Performance Liquid Chromatography (HPLC) analysis and High-Performance Liquid Chromatography Time-Of-Flight Mass Spectrometer (LC-TOF MS). The main carotenoids identified for all three coral species were astaxanthin and a canthaxanthin-like carotenoid. Soft tissue and skeleton of orange L. pertusa contained 2 times more astaxanthin g(-1) wet weight compared to white L. pertusa. White and orange L. pertusa were characterized with in vivo absorbance peaks at 409 and 473 nm, respectively. In vivo absorbance maxima for P. arborea and P. resedaeformis was typically at 475 nm. The shapes of the absorbance spectra (400-700 nm) were species-specific, indicated by in vivo, in vitro and the corresponding difference spectra. The results may provide important chemotaxonomic information for pigment when bonded to their proteins in vivo, bio-prospecting, and for in situ identification, mapping and monitoring of corals.  相似文献   
16.
Climate change is expected to have major effects on the distribution and abundance of fish. In spite of extensive research on the topic in high‐latitude marine ecosystems, the mechanistic understanding of how temperature impacts recruitment and distribution of arcto‐boreal fish stocks remains elusive. Exemplified by an arcto‐boreal gadoid in the Barents Sea, the Northeast Arctic (NEA) haddock (Melanogrammus aeglefinus), we investigate the effect of ecosystem temperature (here temperature from a fixed reference section) on abundance and distribution boundaries between 1981 and 2008. During this time interval there has been a trend of increasing temperature in the ecosystem. We compare the ecosystem temperature with the species habitat temperature of NEA haddock (i.e., ambient temperature of the population) – two temperature approaches representing the indirect and direct environmental impacts on fish, respectively. In addition to the temperature effects, density‐dependent effects on distribution boundaries are considered. The study is based on swept area density estimates and spatial temperature data collected annually in winter surveys. We found a positive relationship between ecosystem temperature and abundance, a connection related to both direct and indirect mechanisms with short‐term and long‐term pathways. Distribution boundaries are, on a year‐to‐year basis, more related to abundance than ecosystem temperature. The long‐term trends, however, indicate a north‐eastward shift in distribution boundaries, probably indirectly related to the coinciding ecosystem temperature increase. In spite of the gradual increase in ecosystem temperature, the abundance of 4‐ to 7‐ year old NEA haddock expanded into colder waters. Thus, our results show how different the two temperature approaches may be.  相似文献   
17.
Norway spruce structural timber is one of the most important products of the Norwegian sawmilling industry, and a high grade-yield of structural timber is therefore important for the economic yield. Presorting of logs suited for production of structural timber might be one option to increase the grade yield. In this study, dynamic modulus of elasticity (Edyn) of structural timber was predicted based on forest inventory data at site level and single-tree data from airborne laser scanning (ALS) and harvester. The models were based on 611 boards from 4 sites in southeastern Norway. Important variables at site level were elevation, site index (SI), and mean stand age. However, when combining data from all information sources, mean stand age and site index were the only significant variables at site level. Tree height and variables describing the crown, like crown length and crown volume, were important vaiables extracted from ALS data. Stem diameter measures and tapering were important variables measured by the harvester. The combined model with variables from all three information sources reduced the variance the most, especially when using individual tree age instead of average stand age. However, combining all these data requires accurate positioning of the trees by the harvester.  相似文献   
18.

Background

According to the Norwegian animal welfare regulations, it has been forbidden to build new tie-stall barns since the end of 2004. Previous studies have shown that cow performance and health differ between housing systems. The interaction between housing system and herd size with respect to performance and disease incidence has not been evaluated.

Methods

Cow performance and health in 620 herds housed in free-stall barns were compared with in 192 herds housed in tie-stall barns based on a mail survey and data from the Norwegian Dairy Herd Recording and Cattle Health Systems. The housing systems herds were comparable with respect to herd size (15-55 cows). Associations between performance/disease incidence and housing system, herd size and year of building the cow barn were tested in general linear models, and values for fixed herd size of 20 and 50 cows were calculated. On the individual cow level mixed models were run to test the effect of among others housing system and herd size on test-day milk yield, and to evaluate lactation curves in different parities. All cows were of the Norwegian Red Breed.

Results

Average milk production per cow-year was 134 kg lower in free-stall herd than in tie-stall herds, but in the range 27-45 cows there was no significant difference in yields between the herd categories. In herds with less than 27 cows there were increasingly lower yields in free-stalls, particularly in first parity, whereas the yields were increasingly higher in free-stalls with more than 45 cows.In free-stalls fertility was better, calving interval shorter, and the incidence rate of teat injuries, ketosis, indigestions, anoestrus and cystic ovaries was lower than in tie-stalls. All of these factors were more favourable in estimated 50-cow herds as compared to 20-cow herds. In the larger herd category, bulk milk somatic cell counts were higher, and the incidence rate of mastitis (all cases) and all diseases was lower.

Conclusion

This study has shown that there is an interaction between housing system and herd size, and that performance and health is not universally better in small free-stalls than in tie-stalls.  相似文献   
19.
Maturing male and female Atlantic salmon (Salmo salar L.) were held under three temperature regimes for 10 weeks between September and December: warm (constant 14–16 °C), ambient (decreasing from 11 to 5 °C), and cold (decreasing from 7 to 3 °C). Blood samples were analyzed for plasma steroid levels, and the fish were inspected for the presence of expressible milt (total volume and spermatocrit) and ovulation weekly. Samples of eggs were dry-fertilized with milt stripped from three males held at the same temperatures and incubated until the eyed stage. In females, levels of plasma testosterone (T) and 17β-oestradiol (E2) dropped as ovulation approached, concurrent with a rapid increase in levels of plasma 17α,20β-dihydroxy-4-pregnen-3-one (17,20β-P). In males, levels of T and 11-ketotestosterone (11-KT) peaked 2–3 weeks after the first appearance of expressible milt, while levels of 17,20β-P increased steadily and did not exhibit a definite peak. Exposure of females to cold water amplified and advanced the profiles of all three steroids compared with the ambient group, and increased the survival rates to the eyed egg stage. Cold water had no immediate effect on the male steroid profiles, but later, higher levels of 17,20β-P were evident compared with both the ambient controls and the warm water group, while the effects on 11-KT and T were more variable. Exposure to warm water completely inhibited both milt production and ovulation. Moreover, warm water modulated the steroid profiles of the males with lower 11-KT levels compared with ambient controls and lower 17,20β-P level compared with cold-water-treated males. In females, warm water resulted in total inhibition of the peri-ovulatory peak in 17,20β-P and prevented the normal decline of T and E2 levels associated with ovulation. The findings of the present study are highly relevant for broodstock management in aquaculture, as well in understanding the impact of climate change/temperature variability on wild salmon spawning.  相似文献   
20.
Data on 216,428 Danish Red, 798,152 Danish Friesian and 232,953 Danish Jersey cows were used to estimate phenotypic and genetic parameters for actual and production‐corrected survival traits and for milk production. Genetic effects of imported breeds were also estimated. Phenotypic trends in days in milk were similar for Danish Red and Danish Friesian, and showed influences of the milk quota system, whereas Danish Jersey showed a continuous downwards trend. Significant additive and non‐additive effects due to imported breeds were found. Heritabilities differed between breeds, ranging from 0.072 to 0.122 for actual continuous lifetime traits, and from 0.048 to 0.076 for production‐corrected continuous lifetime traits. Binary stayability traits showed lower heritability. Genetic correlations between milk production and actual or production‐corrected days in milk were 0.63 and 0.31 respectively. Genetic correlations between binary stayabilities and continuous lifetime traits were high (>0.78), which indicates that stayabilities can be used as early predictors of the lifetime traits.  相似文献   
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