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108.
Genetic and phenotypic parameter estimates for body weights and egg production in Horro chicken of Ethiopia 总被引:1,自引:0,他引:1
Nigussie Dana E. H. vander Waaij Johan A. M. van Arendonk 《Tropical animal health and production》2011,43(1):21-28
A breeding program has been established in 2008 to improve productivity of Horro chicken, an indigenous population in the
western highlands of Ethiopia. The pedigree descended from 26 sires and 260 dams. Body weights were measured every 2 weeks
from hatch to 8 weeks then every 4 weeks for the next 8 weeks. Egg production was recorded to 44 weeks of age for one generation.
Genetic parameters were estimated using animal model fitted with common environmental effects for growth traits and ignoring
common environment for egg production traits. Direct heritabilities ranged from low (0.15 ± 0.08), for body weight at 6 weeks,
to moderate (0.40 ± 0.23), for hatch weight. Heritabilities of common environmental effects on growth were high at hatch (0.39 ± 0.10)
and remained low afterwards. Age at first egg showed a very low heritability (0.06 ± 0.15). Heritabilities of egg numbers
in the first, second, third, and fourth months of laying were 0.32 (±0.13), 0.20 (±0.16), 0.56 (±0.15), and 0.25 (±0.14),
respectively. Heritabilities of cumulative of monthly records of egg numbers were from 0.24 ± 0.16 (for the first 2 months,
EP12) to 0.35 ± 0.16 (over the 6 months, EP16). Body weight at 16 weeks of age (BW16) has a strong genetic correlation with
the cumulative of monthly records: 0.92 (with EP12), 0.69 (with EP36), and 0.73 (with EP16). Besides their strong association,
BW16 and EP16 showed higher heritability, relative to their respective trait categories. These two traits seemed to have common
genes and utilizing them as selection traits would be expected to improve both egg production and growth performance of local
chicken. However, the standard errors of estimates in this study were mostly high indicating that the estimates have low precision.
Parameter estimations based on more data are needed before applying the current results in breeding programs. 相似文献
109.
The infection dynamics of Ascaridia galli in laying hens was investigated in six commercial non-caged flocks. Three flocks were managed in accordance with the regulations for organic production and had outdoor access, whereas three flocks were housed indoors in aviaries or traditional floor systems. Faecal egg counts and total worm burdens were determined at specified intervals during the first 50 weeks of the production period. In two conventional flocks the efficacy of flubendazole on lumenal stages was investigated. All flocks became infected following the arrival of the birds (post placement) with residual infective eggs derived from the previous flock. In four flocks (two organic and two conventional) parasite eggs were first detected in faeces 6-7 weeks post placement, whereas parasite eggs were not detected until after 17-18 weeks in two flocks. This delay was observed in two of three flocks that were housed in barns that had been thoroughly cleaned and disinfected by chlorocresol. In three flocks (two conventional and one organic) flubendazole was administered to the birds in the drinking water for approximately one week. Both conventional flocks were dewormed twice approximately 20 weeks apart, whereas the organic flock was dewormed only once about 40 weeks post placement. Parasite eggs reappeared after deworming in all flocks, often within 2-4 weeks, followed by a rapid increase in parasite egg expulsion. Our results suggested impairment of host immunity post treatment, as the egg counts exceeded pre-treatment levels after 7-8 weeks on both conventional farms. Accordingly, the way by which anthelmintics and/or disinfectants are used in non-caged chicken flocks must be refined. 相似文献
110.
Goddard A Schoeman JP Leisewitz AL Nagel SS Aroch I 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2011,40(3):282-292
Envenomation of domestic animals by snakes occurs frequently in certain geographic areas. However, reports describing clinical signs, clinicopathologic abnormalities, therapeutic approaches, and outcomes are sparse. This review summarizes various snake families, venom types associated with harmful snakes, and the significant hematologic, hemostatic, and biochemical abnormalities associated with envenomation. Hematologic abnormalities include RBC membrane abnormalities, hemolysis, hemoconcentration, leukogram changes, and platelet abnormalities, specifically thrombocytopenia. Coagulopathies associated with snake envenomation are well described in human medicine, and many studies have demonstrated properties of venoms that lead to both procoagulation and anticoagulation. As expected, similar abnormalities have been described in domestic animals. Biochemical abnormalities are associated with the effects of venom on tissues such as liver, skeletal and cardiac muscle, vascular endothelium, and kidney as well as effects on protein components and cholesterol. This comprehensive review of clinicopathologic abnormalities associated with envenomation and their relationships to characterized venom constituents should be useful both in the diagnosis and management of envenomation and should serve as a foundation for future research in this field. 相似文献