全文获取类型
收费全文 | 104篇 |
免费 | 18篇 |
专业分类
林业 | 1篇 |
2篇 | |
综合类 | 14篇 |
水产渔业 | 2篇 |
畜牧兽医 | 101篇 |
园艺 | 1篇 |
植物保护 | 1篇 |
出版年
2023年 | 5篇 |
2021年 | 1篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 1篇 |
2011年 | 3篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 10篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
排序方式: 共有122条查询结果,搜索用时 15 毫秒
71.
72.
Control of nematode parasites with reduced reliance on the use of anthelmintics was studied in 16 ewes with suckling twin lambs on contaminated pasture in Denmark. Ewes and lambs were treated with albendazole at turn-out 3 May. Ewes were removed from the groups on 26 July, and lambs were slaughtered on 11 October. The animals were allocated to 4 groups of 8 lambs and their 4 ewes. Group TS was treated with albendazole at weeks 3, 6 and 8 after turnout and set-stocked; group TM was similarly treated but moved to clean pasture in conjunction with the last drenching; group US was untreated and set-stocked, and group UM was left untreated but moved to clean pasture week 8 after turn-out. Supplementary feed was offered in June and August due to scarcity of pasture. Strategic treatments of ewes and lambs weeks 3, 6 and 8 after turn-out, with or without a move to clean pasture, were highly effective in controlling nematode infections for most of the season. This was reflected in better weight gains and carcass characteristics in the treated compared to untreated lambs, resulting in an average increase in the value of the product by 36%. The effect of moving without treatment (UM) on faecal egg counts was limited but peak pasture infectivity was reduced to less than 10% compared to the set-stocked group and weight gains of lambs were significantly better despite poor feed availability in late season. The study showed that under set-stocked conditions repeated anthelmintic treatments of both ewes and lambs in early season may ensure sufficient nematode control whereas moving animals to clean pasture without dosing was less efficient. The latter may, however, still be a viable option in organic and other production systems where routine use of anthelmintics is banned, particularly if weaning and moving are combined or a second move is performed. 相似文献
73.
M D Tokach J E Pettigrew B A Crooker G D Dial A F Sower 《Journal of animal science》1992,70(6):1864-1872
A regression approach was used to assess quantitatively the influence of lysine and ME intake during lactation on yield of milk components and to determine whether this influence was mediated through precursor metabolite concentrations in the blood. The influence of lysine and energy intake on sow weight and backfat loss also was analyzed by linear regression. Twenty-three primiparous Landrace x Yorkshire sows were fed one of nine corn-soybean meal diets to achieve a matrix of lysine (15, 30, or 45 g/d) and ME (6.5, 11.5, or 16.5 Mcal/d) intakes. Sow BW and backfat losses were found to be predominantly controlled by ME intake (P less than .02), with no response to lysine intake (P greater than .92). Lysine and ME intake explained a smaller portion of the variability in milk component yield on d 8 (R2 less than .34) than on d 22 (R2 = .64 to .78), evidence that dietary effects of milk production increased as lactation progressed. Lysine and ME intake had an interactive influence (P less than .05) on yield of all milk components except lactose, demonstrating that the amount of lysine required to maximize milk production increased as ME intake increased. Strong relationships between diet and most blood precursor metabolite concentrations (R2 = .5 to .7) were detected on d 22. No obvious relationships between precursor metabolite concentrations and milk component yield (R2 = .05 to .2) were observed. These results describe quantitatively the prominent interactive effects of lysine and ME intake on yield of milk components and demonstrate that these effects are not directly associated with changes in precursor pool concentrations. 相似文献
74.
SM Rhind 《Reproduction in domestic animals》2008,43(S2):15-22
Pollutants of many chemical classes, derived primarily from anthropogenic activities, are ubiquitous in the environment, persistent, biologically available and can exert adverse effects on the reproductive and other, indirectly related, physiological systems. Food is generally considered to be the major route of animal exposure in vertebrate species but the relative contributions of other routes of exposure such as through lungs, gills or skin are not well studied and may be of importance for certain animal groups, depending on their immediate environment. Animals are particularly sensitive to exposure during developmental stages but the pattern of exposure to chemicals is likely to be different to that of adults. Quantification of the risk posed by the ingestion of pollutants in food is complex and depends on many factors including species, diet composition, duration of exposure to the food, efficiency of pollutant absorption, subsequent metabolism, sensitivity of target organs and stage of development. While the effects of high doses of single chemicals are proven, dietary exposure to pollutants generally involves prolonged, low-level exposure to a large number of compounds, each of which has different chemical characteristics, exerts different biological effects and is present at varying concentrations. Thus, while exposure to pollutants through feed is undoubtedly a significant risk factor for many species and may be the most important one for many terrestrial vertebrates, other routes of exposure may be more important in other groups. 相似文献
75.
Coccidioidomycosis is a systemic fungal infection endemic to the southwestern United States. Although cell-mediated immunity is considered critical in control of the infection, little is known of the cellular population in naturally occurring lesions. To characterize the lymphocytic infiltration, archived formalin-fixed, paraffin-embedded tissues (subcutis, pericardium/heart, lung, bone, and synovium) from 18 dogs with coccidioidomycosis were studied with immunohistochemistry for CD3 and CD79a. In nearly all lesions, T lymphocytes were more numerous than B lymphocytes and were distributed throughout the lesion with concentration in the periphery of granulomas, whereas B lymphocytes were mostly confined to the periphery of granulomas. The predominance of T lymphocytes in lesions of canine coccidioidomycosis was independent of the tissue evaluated, the number of intralesional organisms, and the nature or severity of the inflammatory response. 相似文献
76.
Polarized and unpolarized neutron scattering was used to measure the wave vector- and frequency-dependent magnetic fluctuations in the normal state (from the superconducting transition temperature, Tc = 35 kelvin, up to 350 kelvin) of single crystals of La1.86Sr0.14CuO4. The peaks that dominate the fluctuations have amplitudes that decrease as T-2 and widths that increase in proportion to the thermal energy, kBT (where kB is Boltzmann's constant), and energy transfer added in quadrature. The nearly singular fluctuations are consistent with a nearby quantum critical point. 相似文献
77.
CC Kneipp AM Rose J Robson R Malik AT Deutscher AK Wiethoelter SM Mor 《Australian veterinary journal》2023,101(4):133-141
Brucella suis is an emerging, zoonotic disease predominantly affecting dogs and humans that engage in feral pig hunting in Australia and other countries. Although B. suis infection in dogs shares some clinical similarities to the host-adapted species (B. canis), B. suis remains an incompletely understood pathogen in dogs with limited published data on its pathogenesis and clinical features. This case series describes the presentations, diagnosis, and clinical management of B. suis infection in three dogs: (1) a bitch with dystocia, abortion and mastitis; (2) an entire male dog with septic arthritis and presumptive osteomyelitis; and (3) a castrated male dog with lymphadenitis. Unique features of these cases are reported including the first documented detection of B. suis from milk and isolation from lymph nodes of canine patients, as well as the follow-up of pups born to a B. suis-infected bitch. Consistent with previous reports, all three dogs showed a favourable clinical response to combination antibiotic therapy with rifampicin and doxycycline. Individually tailored drug regimens were required based on the clinical presentation and other factors, including owner expectations and compliance with therapy as well as a zoonotic risk assessment (generally considered low, except around time of whelping). The authors include their recommendations for the clinical management of dogs that are at-risk or seropositive for B. suis with or without clinical signs or laboratory-confirmed infection. 相似文献
78.
Copper-Catalyzed Oxidation of Alcohols to Aldehydes and Ketones: An Efficient, Aerobic Alternative 总被引:1,自引:0,他引:1
An efficient, copper-based catalyst has been discovered that oxidizes a wide range of alcohols into aldehydes and ketones under mild conditions. This catalytic system utilizes oxygen or air as the ultimate, stoichiometric oxidant, producing water as the only by-product. 相似文献
79.
Objective To investigate tissue residues of two longacting oxytetracycline (OTC) preparations in cattle.
Design A randomised drug residue trial.
Two hundred and forty beef cattle in 24 groups of ten.
Procedure Two blind-coded 200 mg/mL OTC preparations were used in five treatment regimens of various combinations of injection sites (from one to five) and administrations (one or two). Five cattle from each group were slaughtered at 21, 30 and 60 days after injection and the injection site, urine, kidney and diaphragm muscle analysed for residues.
Results The OTC concentration exceeded the maximum residue limit in kidney in animals slaughtered 21 days after treatment, which is the prescribed withholding period. Concentration at the injection site was much greater than the maximum residue limit 30 days post-treatment, but not 45 days post-treatment. The residue was smaller when OTC had been injected in multiple sites. There was no difference between the two OTC preparations.
Conclusion A review of the maximum injection volume, site of injection and the withholding period is needed for long-acting OTC formulations. 相似文献
Design A randomised drug residue trial.
Animals
Two hundred and forty beef cattle in 24 groups of ten.
Procedure Two blind-coded 200 mg/mL OTC preparations were used in five treatment regimens of various combinations of injection sites (from one to five) and administrations (one or two). Five cattle from each group were slaughtered at 21, 30 and 60 days after injection and the injection site, urine, kidney and diaphragm muscle analysed for residues.
Results The OTC concentration exceeded the maximum residue limit in kidney in animals slaughtered 21 days after treatment, which is the prescribed withholding period. Concentration at the injection site was much greater than the maximum residue limit 30 days post-treatment, but not 45 days post-treatment. The residue was smaller when OTC had been injected in multiple sites. There was no difference between the two OTC preparations.
Conclusion A review of the maximum injection volume, site of injection and the withholding period is needed for long-acting OTC formulations. 相似文献
80.
Lulu Rayhan Khushi SM Rubaiot Abdullah Sanjoy Saha Mohammad Raqibul Hasan Siddique 《Southern Forests》2019,81(1):45-48
Gmelina arborea Roxb. is a fast-growing, deciduous tree species native to Bangladesh. It has been widely planted since 1992 for commercial production of pulpwood in hilly areas of Bangladesh. The purpose of this study was to derive well-fitting allometric models for estimation of aboveground biomass, and carbon and nutrient (nitrogen, phosphorus and potassium) stocks in G. arborea to ensure sustainable production and management of this species. Eight linear models with 64 regression equations were tested for estimation of aboveground biomass, carbon and nutrient stocks in different parts (leaves, branches, bark and stem) of the plant. The best-fitting allometric models were selected in accordance with various relevant statistical criteria. 相似文献