全文获取类型
收费全文 | 112篇 |
免费 | 5篇 |
国内免费 | 5篇 |
专业分类
农学 | 4篇 |
基础科学 | 1篇 |
4篇 | |
综合类 | 22篇 |
农作物 | 1篇 |
水产渔业 | 1篇 |
畜牧兽医 | 89篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 10篇 |
2016年 | 1篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 4篇 |
2012年 | 15篇 |
2011年 | 11篇 |
2010年 | 12篇 |
2009年 | 9篇 |
2008年 | 8篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 3篇 |
1999年 | 1篇 |
1997年 | 1篇 |
排序方式: 共有122条查询结果,搜索用时 15 毫秒
1.
2.
A risk-factor study was performed in eight dairy herds found to excrete verocytotoxin-producing Escherichia coli (VTEC) O157 in a former prevalence study. Associations between excretion of VTEC O157 and management factors such as housing and feeding were analysed in a generalised linear mixed model. The animals were stratified in three age groups and sampled four times during 1 year. The risk of excreting VTEC O157 was higher among weaned calves than non-weaned calves. Among the calves aged 1–4 months, the risk was reduced if the calf had suckled colostrum from the mother or if the calf had stayed >2 days with the mother after calving. Calves aged 5–24 months that had been moved within the last 2 weeks had a higher risk, but risk was reduced if fed barley silage. Cows fed grain or molasses had a higher risk of excreting VTEC O157. 相似文献
3.
4.
Hee-Jin Dong Ae-Ri Cho Tae-Wook Hahn Seongbeom Cho 《Journal of veterinary science (Suw?n-si, Korea)》2014,15(2):317-325
A multiplex loop-mediated isothermal amplification (mLAMP) assay was developed for simultaneous detection of the stx1 and stx2 genes and applied for detection of shiga toxin-producing Escherichia coli (STEC) in cattle farm samples. Two target genes were distinguished based on Tm values of 85.03 ± 0.54℃ for stx1 and 87.47 ± 0.35℃ for stx2. The mLAMP assay was specific (100% inclusivity and exclusivity), sensitive (with a detection limit as low as 10 fg/µL), and quantifiable (R2 = 0.9313). The efficacy and sensitivity were measured to evaluate applicability of the mLAMP assay to cattle farm samples. A total of 12 (12/253; 4.7%) and 17 (17/253; 6.7%) STEC O157, and 11 (11/236; 4.7%) non-O157 STEC strains were isolated from cattle farm samples by conventional selective culture, immunomagnetic separation, and PCR-based culture methods, respectively. The coinciding multiplex PCR and mLAMP results for the types of shiga toxin revealed the value of the mLAMP assay in terms of accuracy and rapidity for characterizing shiga toxin genes. Furthermore, the high detection rate of specific genes from enrichment broth samples indicates the potential utility of this assay as a screening method for detecting STEC in cattle farm samples. 相似文献
5.
Nielsen S Frank C Fruth A Spode A Prager R Graff A Plenge-Bönig A Loos S Lütgehetmann M Kemper MJ Müller-Wiefel DE Werber D 《Zoonoses and public health》2011,58(8):567-572
Infection with sorbitol-fermenting Shiga toxin-producing Escherichia coli O157:H- (sf STEC O157:H-) is rare, but emerging in Europe. The pathogen is typically isolated from paediatric patients with life-threatening haemolytic uraemic syndrome (HUS). It is unclear whether this observation primarily reflects the pathogen's virulence or its complex laboratory diagnosis, not routinely conducted in diarrhoeal patients. In summer 2009, four boys living in the same suburb in Germany developed diarrhoea-associated HUS: three were infected by sf STEC O157:H- and one died. We conducted two analytical epidemiological studies, an extensive search for diarrhoeal cases in potentially exposed groups, and an environmental investigation. Outbreak cases were residents of the suburb diagnosed with HUS, sf STEC O157:H- infection, or both between 24 July 2009 and 25 August 2009. Overall, we ascertained eight cases with a median age of 4 years (range: from 8 months to 9 years). Stool screening of 220 persons led to the identification of only four additional cases: two asymptomatic carriers and two diarrhoeal cases. HUS was strongly associated with visiting a local playground in July, particularly on 16th July (odds ratio = 42.7, P = 0.002). No other commonality, including food, was identified, and all environmental samples (n = 24) were negative. In this localized non-foodborne outbreak, the place of likely infection was a local playground. Sf STEC O157:H- infection apparently limits itself rarely to diarrhoeal illness and progresses frequently to HUS. Therefore, detection of and response to this hypervirulent pathogen primarily relies on HUS surveillance. 相似文献
6.
Cernicchiaro N Pearl DL McEwen SA Harpster L Homan HJ Linz GM Lejeune JT 《Zoonoses and public health》2012,59(5):320-329
Our objective was to determine the role that European starlings (Sturnus vulgaris) play in the epidemiology of Escherichia coli O157:H7 in dairy cattle. We visited 150 dairy farms in Ohio twice during summer and fall months from 2007 to 2009. Fresh faecal pats from 30 lactating cows were collected during each visit. Information on farm management and environmental variables was gathered through a questionnaire administered to the farm owner. The number of starlings observed on the farm was also recorded. Approximately 1% of dairy cattle and 24% of farms were positive for E. coli O157. Risk factors associated with the presence of E. coli O157 in faecal pats included contact between adult cattle and calves, types or number of ventilation and manure management systems and number of birds per milking cow. 相似文献
7.
Background
In the less-sensitive mouse model, Shiga toxin-producing Escherichia coli (STEC) challenges result in shedding that reflect the amount of infection and the expression of virulence factors such as Shiga toxins (Stx). The purpose of this study was to characterize the contribution of STEC diversity and Stx expression to shedding in beef feeder calves and to evaluate the effectiveness of a prebiotic, Celmanax®, to alleviate STEC shedding. Fecal samples were collected from calves at entry and after 35 days in the feedlot in spring and summer. STECs were evaluated using selective media, biochemical profile, serotyping and Stx detection. Statistical analysis was performed using repeated measures ANOVA and logistic regression.Results
At entry, non-O157 STEC were dominant in shedding calves. In spring, 21%, 14% and 14% of calves acquired O157, non-O157 and mixed STEC infections, respectively. In contrast, 45%, 48% and 46% of calves in summer acquired O157, non-O157 and mixed STEC infections, respectively. Treatment with a prebiotic, Celmanax®, in spring significantly reduced 50% of the O157 STEC infections, 50% of the non-O157 STEC infections and 36% of the STEC co-infections (P = 0.037). In summer, there was no significant effect of the prebiotic on STEC infections. The amount of shedding at entry was significantly related to the number and type of STECs present and Stx expression (r2 = 0.82). The same relationship was found for shedding at day 35 (r2 = 0.85), but it was also related to the number and type of STECs present at entry. Stx - producing STEC infections resulted in 100 to 1000 × higher shedding in calves compared with Stx-negative STECs.Conclusions
STEC infections in beef feeder calves reflect the number and type of STECs involved in the infection and STEC expression of Stx. Application of Celmanax® reduced O157 and non-O157 STEC shedding by calves but further research is required to determine appropriate dosages to manage STEC infections. 相似文献8.
Bacillus velezensis 157混合固态发酵生产多种木质纤维素酶的发酵条件优化 总被引:1,自引:0,他引:1
为论证单一固态Bacillus velezensis 157发酵豆粕中混合碱处理玉米秸秆能否有利于提高内切葡聚糖酶、淀粉酶、木聚糖酶和果胶酶的产酶量,利用DNS法对碱处理玉米秸秆与豆粕混合添加质量比进行优化后,采用单因素法分别对单一发酵豆粕、碱处理玉米秸秆以及混合发酵碱处理玉米秸秆-豆粕中底物与水分质量比、发酵温度以及发酵时间进行优化,并对发酵过程中B.velezensis 157的生长曲线进行测定。结果表明:经发酵条件优化后,以碱处理玉米秸秆和豆粕的质量比为1.0∶1.0,底物与水分质量比为1.0∶0.5;B.velezensis 157于37℃培养温度下发酵24 h后,混合发酵组的内切葡聚糖酶、淀粉酶、木聚糖酶、果胶酶以及菌落数,均高于单一发酵碱处理玉米秸秆组和豆粕组,酶活力分别可达56.83±1.47、1 949.28±14.41、16.52±0.79和14.53±0.56 U/g,相应酶活力与碱处理玉米秸秆组相比,分别提高了7.81、6.41、1.23和2.53倍;与豆粕组相比,分别提高了1.17、1.35、1.07和1.21倍;同时,混合发酵组中B.velezensis 157菌落数高于豆粕组和碱处理秸秆组。因此,B.velezensis 157混合固态发酵有利于提高B.velezensis 157内切葡聚糖酶、木聚糖酶、淀粉酶和果胶酶的酶产量,节约了时间和成本,为动物饲料酶制剂和生物饲料的开发提供依据。 相似文献
9.
10.