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51.
ARB HIGGS RT NORRIS FC BALDOCK NJ CAMPBELL S. KOH RB RICHARDS 《Australian veterinary journal》1996,74(3):215-220
Objective: To investigate control options for contagious ecthyma (scabby mouth) in Australian sheep exported live to the Middle East.
Design: Prevalence, vaccination and modelling studies.
Procedure: One hundred and forty weaner sheep (less than 1 year old) on each of 106 farms in Western Australia (WA) and 18 farm groups of adult wethers received at a WA commercial feedlot were examined for lesions of scabby mouth. Sheep on a total of 26 farms in 3 States were divided into treatment and control groups for the vaccination study. A simple deterministic compartmental model was developed to establish which parameters had the greater effect on disease prevalence.
Results: The proportion of farms with evidence of scabby mouth in weaner sheep was 23.6% and, on those farms with the disease, the overall prevalence was 6.1%. At the feedlot, 4 out of 18 farm groups had 5 or more sheep with lesions on arrival. The overall prevalence in the 4 diseased groups was 5.2%. Sheep vaccinated on farm before trucking to the feed-lot had a lower prevalence of scabby mouth at the end of simulated shipping than controls. The main determinant of scabby mouth prevalence was the proportion of sheep immune to the disease.
Conclusion: A program of vaccination for scabby mouth will reduce the prevalence of disease during live export. However, using current technology it is not possible to deliver shipments of sheep to the Middle East that are guaranteed completely free of scabby mouth. 相似文献
Design: Prevalence, vaccination and modelling studies.
Procedure: One hundred and forty weaner sheep (less than 1 year old) on each of 106 farms in Western Australia (WA) and 18 farm groups of adult wethers received at a WA commercial feedlot were examined for lesions of scabby mouth. Sheep on a total of 26 farms in 3 States were divided into treatment and control groups for the vaccination study. A simple deterministic compartmental model was developed to establish which parameters had the greater effect on disease prevalence.
Results: The proportion of farms with evidence of scabby mouth in weaner sheep was 23.6% and, on those farms with the disease, the overall prevalence was 6.1%. At the feedlot, 4 out of 18 farm groups had 5 or more sheep with lesions on arrival. The overall prevalence in the 4 diseased groups was 5.2%. Sheep vaccinated on farm before trucking to the feed-lot had a lower prevalence of scabby mouth at the end of simulated shipping than controls. The main determinant of scabby mouth prevalence was the proportion of sheep immune to the disease.
Conclusion: A program of vaccination for scabby mouth will reduce the prevalence of disease during live export. However, using current technology it is not possible to deliver shipments of sheep to the Middle East that are guaranteed completely free of scabby mouth. 相似文献
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基因疫苗是近几年来发展起来的一种新型疫苗,具有使用安全,生产、运输、贮存方便,免疫效果稳定持久的特点。实验采用PCR方法将从洛阳种牛场西门塔尔牛精液中分离的牛传染性鼻气管炎(Infectious bovine rhino—traeheitis virus,IBRV)洛精株gD基因进行了扩增,经序列测定确证后构建了gD基因的真核表达质粒。将其单独或连同脂质体肌肉注射于BALB/c小鼠,应用ELISA定期检测血清抗体水平。结果表明,含IBRV gD基因的表达质粒能够引起小鼠的特异性血清抗体反应。 相似文献
55.
N Zygraich F Renaut J Gits 《Comparative immunology, microbiology and infectious diseases》1978,1(1-2):59-66
Aerosol administrations of RIT 4030 and other available vaccine strains have been carried out in SPF and in conventional chickens. The results indicate that the RIT 4030 and Ulster 2C strains are significantly less reactogenic than the LaSota and the Hitchner B1 strains.The RIT 4030 strain produces an immune response even when administered to chickens with maternal antibodies and induces a better protection to challenge than the Ulster 2C strain.The replication of the RIT 4030 strain in the respiratory tract will be discussed with respect to its attenuation and transmissibility. 相似文献
56.
Twenty days after an open castration, a 5-year-old dromedary was presented to the Dubai Camel Hospital with severe central nervous symptoms. The dromedary showed the following signs: off feed, stiff gait with extended neck, external swelling of the preputial sheath and groin region, and foamy saliva drooling from the mouth. The dromedary was unable to swallow. Three days after admission, the camel developed lockjaw, and on the fifth day it was unable to stand owing to paralysis of the hindquarters. Because of the severity of the disease and because it did not respond to treatment, the camel was euthanized 26 days after the operation and submitted to the Central Veterinary Research Laboratory for further investigation. Both castration wounds were closed and spermiducts were filled with necrotic masses from which Clostridium tetani was isolated. Two mice, which were injected with the filtrate of the thioglycolate broth, developed typical signs of tetanic spasm of the hind leg. Faecal samples from camel and horse paddocks that were only 50 metres apart were negative for C. tetani. However, C. tetani was isolated from two soil samples of the horse paddock. It is recommended that camels should be vaccinated against tetanus prior to castration. 相似文献
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为了高效表达狂犬病病毒HEP-Flury的核蛋白,选取抗原决定簇富集区,利用生物信息学技术分析了狂犬病病毒HEP-Flury N蛋白的核苷酸序列.根据大肠埃希菌Escherichia coli对密码子的偏嗜性,首先对所选取的核苷酸序列进行修饰、引入酶切位点,然后定向克隆至原核表达载体pET-32a(+),构建重组质粒pET-32-NP.将其转化表达宿主菌Escherichia coli BL21(DE3)pLysS,以IPTG诱导表达.表达产物经SDS-PAGE电泳,发现在相对分子质量34 000处有1条特异的蛋白带,与预期大小一致.Western-blotting检测结果显示,该蛋白可被鼠抗His单克隆抗体及犬抗RV多克隆抗体特异识别,表明所表达的N蛋白具有良好的免疫原性. 相似文献
59.
为了有效监测犬免疫狂犬病疫苗后的保护效力,以狂犬病毒(Rabies virus,RV)糖蛋白的主要优势抗原表位区G3蛋白(RV G3)作为包被抗原,建立了一种检测狂犬病毒中和抗体效价的间接ELISA方法.通过优化反应条件,确定抗原最佳包被量为8 mg/L,血清的最佳稀释度为1∶100,酶标二抗的稀释度为1∶3 000.特异性试验表明,该抗原不与犬瘟热病毒、犬腺病毒、犬细小病毒阳性血清发生交叉反应;批内和批间重复性试验的平均变异系数都小于10%;敏感性达1∶1 280.此方法检测134份血清样品的结果与美国SYNBIOTICS试剂盒相比,总符合率达95.6%. 相似文献
60.
选择17头28日龄的CSFV和PRRSV抗体均为阴性的仔猪,于试验的第1天和第14天分别对其进行猪瘟耐热保护剂活疫苗(兔源)和高致病性猪繁殖与呼吸综合征Nsp2A1882—2241弱毒疫苗免疫。在免疫后的第28、42天采集外周血液,分析特异性抗体表达量和外周血T淋巴细胞表型的变化,评估猪瘟免疫对猪繁殖与呼吸综合征免疫的影响。结果显示,在CSF免疫后第28、42天,CSFV高抗组中的CD4^+、CD4^+/CD8^+、CD4^+CD8^+和CD4-CD8数目均比CSFV低抗组高,CD3^+和CD8^+细胞数量比CSFV低抗组低;PRRS高抗组中,CD4CD8-细胞含量高于PRRS低抗组;在CSF免疫后第28天,CSFV抗体产生较高(阳性比率为73.33%),PRRSV抗体产生较低(阳性比率仅为6.67%)。在CSF免疫后的第42天,CSF高抗组中PRRSV抗体阳性比率较CSF低抗组高8.33%。结果表明,CSFV特异性抗体产生高时能增加PRRSV特异性细胞免疫应答,增加CD4^+细胞、CD4^+CD8^+细胞数量,提高机体免疫水平。CD3+和CD4CD8-细胞应答作用值得重视。 相似文献