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1.
Dorothee Ehrich Maite Cerezo Anna Y. Rodnikova Natalya A. Sokolova Eva Fuglei Victor G. Shtro Aleksandr A. Sokolov 《BMC ecology》2017,17(1):32
Background
High latitude ecosystems are at present changing rapidly under the influence of climate warming, and specialized Arctic species at the southern margin of the Arctic may be particularly affected. The Arctic fox (Vulpes lagopus), a small mammalian predator endemic to northern tundra areas, is able to exploit different resources in the context of varying tundra ecosystems. Although generally widespread, it is critically endangered in subarctic Fennoscandia, where a fading out of the characteristic lemming cycles and competition with abundant red foxes have been identified as main threats. We studied an Arctic fox population at the Erkuta Tundra Monitoring site in low Arctic Yamal (Russia) during 10 years in order to determine which resources support the breeding activity in this population. In the study area, lemmings have been rare during the last 15 years and red foxes are nearly absent, creating an interesting contrast to the situation in Fennoscandia.Results
Arctic fox was breeding in nine of the 10 years of the study. The number of active dens was on average 2.6 (range 0–6) per 100 km2 and increased with small rodent abundance. It was also higher after winters with many reindeer carcasses, which occurred when mortality was unusually high due to icy pastures following rain-on-snow events. Average litter size was 5.2 (SD = 2.1). Scat dissection suggested that small rodents (mostly Microtus spp.) were the most important prey category. Prey remains observed at dens show that birds, notably waterfowl, were also an important resource in summer.Conclusions
The Arctic fox in southern Yamal, which is part of a species-rich low Arctic food web, seems at present able to cope with a state shift of the small rodent community from high amplitude cyclicity with lemming dominated peaks, to a vole community with low amplitude fluctuations. The estimated breeding parameters characterized the population as intermediate between the lemming fox and the coastal fox ecotype. Only continued ecosystem-based monitoring will reveal their fate in a changing tundra ecosystem.2.
3.
Zavalin A. A. Sokolov O. A. Shmyreva N. Ya. Lukin S. V. Awilow A. S. 《Eurasian Soil Science》2022,55(1):56-63
Eurasian Soil Science - The nitrogen of organic fertilizers contributes to stabilization of nitrogen cycles and sustainable development of agroecosystems. The application of green manure biomass as... 相似文献
4.
A method to select measures for enhancing natural forest-regeneration process in areas under extensive management is discussed. Using available information on geomorphological site characteristics and stand parameters, indices are determined using a specific criterion that describes the forest regeneration process. Using these indices as model inputs, clearcuts and burns can be classified; within each stratum the natural forest regeneration process is similar. Analysing these strata, one can select a regime of forest treatment that is appropriate for a given stratum and, consequently, for the clearcuts (or burns) it includes. 相似文献
5.
Preparation on the basis of Trichoderma asperellum in the system of biological protection of wheat from Fusarium ear scab 下载免费PDF全文
During the last century, as the area of wheat grown under advanced grain husbandry has increased worldwide, so too has the importance of Fusarium ear scab (FES) (synonym, Fusarium head blight) caused by several species of the fungus Fusarium. Yield losses due to FES can total 20%-40% and more depending on climatic conditions. During the last twenty years epidemics of FES in cereals have become chronic all over the world, including the United States and Russia. The most destructive of t… 相似文献
6.
Piro L Garmire G Garcia M Stratta G Costa E Feroci M Mészáros P Vietri M Bradt H Frail D Frontera F Halpern J Heise J Hurley K Kawai N Kippen RM Marshall F Murakami T Sokolov VV Takeshima T Yoshida A 《Science (New York, N.Y.)》2000,290(5493):955-958
We report on the discovery of two emission features observed in the x-ray spectrum of the afterglow of the gamma-ray burst (GRB) of 16 December 1999 by the Chandra X-ray Observatory. These features are identified with the Ly(alpha) line and the narrow recombination continuum by hydrogenic ions of iron at a redshift z = 1.00 +/- 0.02, providing an unambiguous measurement of the distance of a GRB. Line width and intensity imply that the progenitor of the GRB was a massive star system that ejected, before the GRB event, a quantity of iron approximately 0.01 of the mass of the sun at a velocity approximately 0.1 of the speed of light, probably by a supernova explosion. 相似文献
7.
The qualitative indices of coextruded products obtained from a multicomponent mixture of grain products having a high protein content are investigated. The extrudates have a high nutritional and energy value as well as balanced protein-carbohydrate and amino acid compositions. 相似文献
8.
9.
A. S. Avilov S. V. Lukin N. Ya. Shmyreva A. A. Zavalin O. A. Sokolov 《Russian Agricultural Sciences》2018,44(3):245-249
It is shown that an increase in winter wheat on typical chernozem characterized by the acid reaction of the soil medium leads to a decrease in grain yield to 30% and straw weight to 25%. The crop reached the maximum level after introducing urea and manure wastes (the yield gain was 199% in neutral soil and 165% in acidic soil). The improvement of plant nitrogen nutrition by introducing fertilizers led to an increase in the protein content in grain by 1.2 times on both soils; at the same time, the protein content was 1.1 times lower in acidic soil than in the neutral one. The maximum content of protein in winter wheat grain accumulated after both types of fertilizers were applied on neutral soil; the use of manure wastes alone decreased the protein content in grain. It has been revealed that a decrease in the yield of grain and a decrease in the content of crude protein in this grain after acidification of typical chernozem is due to a decrease in the amount of mineral nitrogen in soil and an increase in its gaseous losses. The pattern of nitrogen transformation in soil, as well as the availability of nitrogen for the plants, varied as the reaction of the medium changed. In acidic soil, the consumption of mineral fertilizer nitrogen and manure wastes by the plants decreased by 12–13% and the consumption of soil nitrogen decreased by 45%. The effect of wastes decreased the consumption of urea nitrogen by 49% (neutral soil) and by 69% (acidic soil). The consumption of fertilizer nitrogen by the plants decreased by 12–15% after acidifying typical chernozem and by 12–17% after immobilizing this type of chernozem and increased gaseous losses by 18–81%. It has been concluded that the agrophytocenosis of winter wheat maintains the ecological balance (homeostasis) when wastes from a pig-breeding complex are used and is exposed to stress when urea is applied in acid chernozem. Soil acidification decreased the resistance of agrophytocenosis to the level that is observed when manure wastes were applied and to adaptive depletion when urea was used. 相似文献
10.
Specific features of the development of redox systems in the soils of coal mine dumps in Kemerovo oblast were studied. The
quantitative characteristics of the fractional composition of the oxidized and reduced components in these soils were obtained,
and their heterogeneity was shown. Distribution patterns of the reduced and oxidized components in the parent material of
these specific technogenic landscapes in the course of soil evolution were revealed. 相似文献