全文获取类型
收费全文 | 41130篇 |
免费 | 1293篇 |
国内免费 | 10篇 |
专业分类
林业 | 4478篇 |
农学 | 2039篇 |
基础科学 | 287篇 |
6335篇 | |
综合类 | 4226篇 |
农作物 | 2984篇 |
水产渔业 | 3115篇 |
畜牧兽医 | 14205篇 |
园艺 | 1360篇 |
植物保护 | 3404篇 |
出版年
2019年 | 252篇 |
2018年 | 3125篇 |
2017年 | 3174篇 |
2016年 | 1649篇 |
2015年 | 403篇 |
2014年 | 479篇 |
2013年 | 970篇 |
2012年 | 1579篇 |
2011年 | 3055篇 |
2010年 | 2762篇 |
2009年 | 1912篇 |
2008年 | 2264篇 |
2007年 | 2471篇 |
2006年 | 836篇 |
2005年 | 834篇 |
2004年 | 744篇 |
2003年 | 854篇 |
2002年 | 663篇 |
2001年 | 807篇 |
2000年 | 839篇 |
1999年 | 634篇 |
1998年 | 275篇 |
1997年 | 282篇 |
1995年 | 260篇 |
1994年 | 227篇 |
1993年 | 244篇 |
1992年 | 431篇 |
1991年 | 516篇 |
1990年 | 435篇 |
1989年 | 415篇 |
1988年 | 411篇 |
1987年 | 410篇 |
1986年 | 363篇 |
1985年 | 388篇 |
1984年 | 339篇 |
1983年 | 287篇 |
1982年 | 243篇 |
1979年 | 383篇 |
1978年 | 289篇 |
1977年 | 294篇 |
1976年 | 300篇 |
1975年 | 317篇 |
1974年 | 332篇 |
1973年 | 302篇 |
1972年 | 291篇 |
1971年 | 245篇 |
1969年 | 290篇 |
1968年 | 273篇 |
1967年 | 327篇 |
1966年 | 304篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
I Gunsser T H?nichen J Maierl 《Tier?rztliche Praxis. Ausgabe G, Grosstiere/Nutztiere》1999,27(3):187-192
In Llamas and Alpacas infestation with Fasciola hepatica or Dicrocoelium dendriticum can cause liver damage, sometimes even with lethal outcome. Once infected South American Camelids (SACs) react more sensitively to these parasites than other domestic ruminants. We report here on the pathology, parasitology, clinics and therapy of this disease. Concerning Dicrocoelium dendriticum we describe own clinical results and therapeutic outcome in addition to the pathological investigation. According to anatomic corrosion casts, the bile ducts of SACs show more similarity with the equine bile system than with the bile system of domestic ruminants. 相似文献
82.
83.
84.
85.
86.
87.
Blanco I Galina-Pantoja L Oliveira S Pijoan C Sánchez C Canals A 《Veterinary microbiology》2004,103(1-2):21-27
The aim of this study was to compare the development of Glasser's disease in sow-reared and colostrum-deprived piglets. Ninety piglets from a commercial pig farm in Spain were used. The farm was positive for Haemophilus parasuis. Fifty-two pigs were sow-reared (SR) and 38 were colostrum-deprived (CD) piglets. The animals were intratracheally inoculated with H. parasuis serovar 5 and sacrificed at 1, 2 and 3 days post-infection. To assess the development of disease, antibody titers, clinical signs, pathological lesions, microbiological isolation and PCR amplification were compared between the groups. Inoculation of SR pigs did not cause clinical signs or lesions of Glasser's disease. In SR pigs, H. parasuis isolation and specific PCR amplification from tissues showed a very low number of positive samples. In contrast, in CD pigs, inoculation resulted in the typical signs and lesions of Glasser's disease. Positive microbiological isolation and specific PCR products were obtained from the majority of the tissues tested, and no antibodies against H. parasuis were detected. The experimental infection using CD pigs describes a successful method to study this microorganism and confirms the important role that maternal antibodies play in protection against clinical signs and disease. 相似文献
88.
Awareness of animal influenza and its prevention and control is important for ensuring livestock health, production and welfare. In China, a country stereotyped as a major source of emerging zoonotic infectious diseases, research on the public understanding of animal influenza is limited to the Han, the main ethnic group. The present qualitative study in Southwest China investigated awareness of animal influenza among the Dai, an ethnic minority. The participants (15 men and 10 women, ages 18–83) were smallholder farmers of pigs and poultry in rural areas of Jinghong, Xishuangbanna, Yunnan Province. A mixture of interviews and group discussions took place in homes and villages. The participants were asked about their knowledge of avian influenza (H7N9), swine influenza (H1N1), precautions taken to protect against influenza, procedures when animals were sick and perceived risk of animal influenza. The data were analysed following coding and thematic analysis. The findings demonstrated a limited understanding of animal health and welfare among participants. Specifically, they were largely unaware of animal influenza (H7N9, H1N1) including its causes, symptoms, prevention and treatment. The farmers were also uninformed of the risks they faced and unknowingly engaged in behaviours which increased direct or indirect exposure to infected animals, a risk factor for human infection. They also reported poor usage of veterinary services. In order to guarantee the health, welfare and production of their livestock, immediate action is needed to enable Dai smallholder farmers to prevent and respond to animal influenza effectively and timely. 相似文献
89.
Phiri AM Phiri IK Sikasunge CS Chembensofu M Monrad J 《The Onderstepoort journal of veterinary research》2006,73(4):275-281
After dissecting 70 condemned and 32 non-condemned cattle livers collected from Lusaka, Chisamba, Mongu and Senanga abattoirs and Turnpike slaughter slab, significantly higher numbers of liver flukes (Fasciola gigantica) (P < 0.001) were found in the condemned livers (mean +/- SD = 100.6 +/- 16.7) than in the non-condemned livers (mean +/- SD = 0.7 +/- 0.5). Liver flukes found in 9.4% of the non-condemned livers suggest that abattoir records of liver inspection may underestimate F. gigantica infections. Average faecal fluke egg counts from animals with condemned livers (5 eggs per gram [EPG]) were significantly higher (P < 0.001) than in animals with non-condemned livers (0.8 EPG). No correlation was found between egg counts and number of flukes. Fibrosis and calcification were common in condemned livers, being severest in the vicinity of the bile ducts. Only two (6.3%) of the non-condemned livers showed pathological changes on the liver edges. The severe liver damage and high worm burden may explain low production levels experienced in cattle in Zambia maintained under traditional systems of management where worm control and good management programmes are rarely practiced. 相似文献
90.