全文获取类型
收费全文 | 5260篇 |
免费 | 277篇 |
国内免费 | 261篇 |
专业分类
林业 | 840篇 |
农学 | 239篇 |
基础科学 | 159篇 |
265篇 | |
综合类 | 2196篇 |
农作物 | 238篇 |
水产渔业 | 161篇 |
畜牧兽医 | 1084篇 |
园艺 | 241篇 |
植物保护 | 375篇 |
出版年
2024年 | 40篇 |
2023年 | 93篇 |
2022年 | 125篇 |
2021年 | 207篇 |
2020年 | 170篇 |
2019年 | 244篇 |
2018年 | 91篇 |
2017年 | 137篇 |
2016年 | 239篇 |
2015年 | 189篇 |
2014年 | 352篇 |
2013年 | 316篇 |
2012年 | 439篇 |
2011年 | 430篇 |
2010年 | 330篇 |
2009年 | 328篇 |
2008年 | 264篇 |
2007年 | 278篇 |
2006年 | 251篇 |
2005年 | 184篇 |
2004年 | 147篇 |
2003年 | 128篇 |
2002年 | 107篇 |
2001年 | 103篇 |
2000年 | 87篇 |
1999年 | 94篇 |
1998年 | 75篇 |
1997年 | 48篇 |
1996年 | 33篇 |
1995年 | 41篇 |
1994年 | 34篇 |
1993年 | 25篇 |
1992年 | 24篇 |
1991年 | 22篇 |
1990年 | 25篇 |
1989年 | 29篇 |
1988年 | 20篇 |
1987年 | 19篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有5798条查询结果,搜索用时 15 毫秒
91.
江苏某鸡场饲养的蛋鸡,呼吸道病很严重,用药物和现有的疫苗控制效果都不够理想。为此,将该鸡场发生呼吸道病病鸡的病料进行收集,制成油佐剂灭活苗对鸡进行免疫接种,结果获得满意的效果。 相似文献
92.
93.
94.
95.
Basma M. Sheta Trevon L. Fuller Brenda Larison Kevin Y. Njabo Ahmed Samy Ahmed Ryan Harrigan Anthony Chasar Soad Abdel Aziz Abdel-Aziz A. Khidr Mohamed M. Elbokl Lotfy Z. Habbak Thomas B. Smith 《Veterinary microbiology》2014
Highly pathogenic influenza A virus subtype H5N1 causes significant poultry mortality in the six countries where it is endemic and can also infect humans. Egypt has reported the third highest number of poultry outbreaks (n = 1084) globally. The objective of this cross-sectional study was to identify putative risk factors for H5N1 infections in backyard poultry in 16 villages in Damietta, El Gharbia, Fayoum, and Menofia governorates from 2010–2012. Cloacal and tracheal swabs and serum samples from domestic (n = 1242) and wild birds (n = 807) were tested for H5N1 via RT-PCR and hemagglutination inhibition, respectively. We measured poultry rearing practices with questionnaires (n = 306 households) and contact rates among domestic and wild bird species with scan sampling. Domestic birds (chickens, ducks, and geese, n = 51) in three governorates tested positive for H5N1 by PCR or serology. A regression model identified a significant correlation between H5N1 in poultry and the practice of disposing of dead poultry and poultry feces in the garbage (F = 15.7, p < 0.0001). In addition, contact between domestic and wild birds was more frequent in villages where we detected H5N1 in backyard flocks (F = 29.5, p < 0.0001). 相似文献
96.
Autochthonous Chagas disease in the southern United States: A case report of suspected residential and military exposures 下载免费PDF全文
N. Harris L. Woc‐Colburn S. M. Gunter R. Gorchakov K. O. Murray S. Rossmann M. N. Garcia 《Zoonoses and public health》2017,64(6):491-493
Chagas disease is a parasitic infection that can result in a progressive dilated cardiomyopathy. Here, we present the epidemiologic details of a suspected locally acquired transmission case originating from the southern United States. This is the first published report of Chagas disease in a young, healthy United States veteran with repeat triatomine exposures in Arizona. Military personnel and Arizona residents should be aware of their Chagas disease transmission risks. 相似文献
97.
Prevention of intestinal parasites in a tri‐border area of Latin America: Children perceptions and an integral health education strategy 下载免费PDF全文
M. R. Rivero M. M. Salas R. Valente M. J. Nores C. De Angelo J. Arrabal S. Costa O. D. Salomón 《Zoonoses and public health》2017,64(8):673-683
To investigate knowledge of school‐aged children and their perception on intestinal parasites, and to assess knowledge reconstruction on prevention practices after specific training in the subject. We performed an activity package that included the analysis of children's drawings of intestinal parasites, and information and communication technologies (ITCs) to transfer knowledge about these pathogens and prevention measures. Retrieval learning activities were performed to fixation of general and specific prevention and control measures.Overall, we found that there is a knowledge gap in many aspects of parasite biology and ecology, and therefore on the risk of infection and acquisition mechanisms. After ITCs, the children improved their knowledge over non‐trained children.The approaches used to transfer knowledge and for learning, fixation were valuable tools for incorporating changes in misconceptions and in the deep‐rooted habits that favour entero‐parasitic diseases. This has important implications for the specific design of future education materials and campaigns. Understanding of perceptions helps to provide justifications and knowledge to achieve changes in unhealthy habits, and it constitutes the basis for the transformation of many risky practices. 相似文献
98.
99.
选择平均体重为26.6kg的无角多赛特断奶大羔羊22只.平均体重为49.3kg的无角多赛特育成羊48只,分别分为对照组和试验组,试验组羊只精料补充料中添加300mg/kg的茶黄酮,研究茶黄酮对羊只生长和呼吸道疾病的影响。结果表明,添加茶黄酮可提高羔羊和育成羊的增重效果.和对照组比较羔羊提高增量9.8%(P〉0.05),育成羊提高增重6.1%(P〉0.05);在饲料中添加茶黄酮可使羔羊呼吸道疾病发病率降低64%,使育成羊呼吸道疾病发病率降低50%,可有效预防羊的呼吸道疾病。 相似文献
100.
安徽省鸡免疫抑制性疾病的流行病学调查 总被引:8,自引:0,他引:8
采集了安徽省6个主要养鸡地区65群鸡的185只病鸡共986份组织样品,对可引起免疫抑制性疾病的5种最常见病毒进行了PCR检测。结果,传染性腔上囊病病毒(IBDV)、鸡传染性贫血病毒(CIAV)、马立克氏病病毒(MDV)、禽白血病病毒(ALV)和网状内皮增生症病毒(REV)的群阳性率和个体阳性率分别为73.08%和40.91%、46.15%和25.95%、41.54%和17.84%、18.46%和7.57%、13.85%和4.86%,其中被检鸡之二重或多重混合感染的总阳性率为24.33%。调查结果证实,免疫抑制性疾病在安徽省的商业鸡群中普遍存在,并与鸡群疾病多而复杂、损失大相关。 相似文献