全文获取类型
收费全文 | 11761篇 |
免费 | 3625篇 |
国内免费 | 38篇 |
专业分类
林业 | 459篇 |
农学 | 716篇 |
基础科学 | 45篇 |
2301篇 | |
综合类 | 756篇 |
农作物 | 725篇 |
水产渔业 | 2832篇 |
畜牧兽医 | 5943篇 |
园艺 | 84篇 |
植物保护 | 1563篇 |
出版年
2023年 | 32篇 |
2022年 | 113篇 |
2021年 | 257篇 |
2020年 | 564篇 |
2019年 | 1125篇 |
2018年 | 1012篇 |
2017年 | 1062篇 |
2016年 | 1080篇 |
2015年 | 963篇 |
2014年 | 989篇 |
2013年 | 1228篇 |
2012年 | 804篇 |
2011年 | 892篇 |
2010年 | 823篇 |
2009年 | 479篇 |
2008年 | 548篇 |
2007年 | 394篇 |
2006年 | 387篇 |
2005年 | 337篇 |
2004年 | 328篇 |
2003年 | 278篇 |
2002年 | 309篇 |
2001年 | 223篇 |
2000年 | 232篇 |
1999年 | 95篇 |
1998年 | 41篇 |
1997年 | 32篇 |
1996年 | 35篇 |
1995年 | 28篇 |
1994年 | 21篇 |
1993年 | 33篇 |
1992年 | 31篇 |
1991年 | 29篇 |
1990年 | 41篇 |
1989年 | 40篇 |
1988年 | 34篇 |
1987年 | 41篇 |
1986年 | 20篇 |
1985年 | 33篇 |
1984年 | 24篇 |
1983年 | 29篇 |
1981年 | 20篇 |
1978年 | 27篇 |
1977年 | 24篇 |
1976年 | 29篇 |
1975年 | 17篇 |
1974年 | 23篇 |
1973年 | 23篇 |
1972年 | 22篇 |
1970年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Reducing copper use in the environment: the use of larixol and larixyl acetate to treat downy mildew caused by Plasmopara viticola in viticulture 下载免费PDF全文
52.
53.
54.
55.
56.
Analgesic efficacy of an oral transmucosal spray formulation of meloxicam alone or in combination with tramadol in cats with naturally occurring osteoarthritis 下载免费PDF全文
57.
58.
Kim TY Kim YS Kim JK Shon HJ Lee YH Kang CB Park JS Kang KS Lee YS 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(8):743-752
The occurrence of Bovine Spongiform Encephalopathy (BSE, so called mad cow diseases) that was first identified in England in 1986 was considered as being limited to only European countries, including England. However, the outbreak in Asia as well as North America since 2001 has amplified the fear that there isn't any nation in the world that is a safe area. In order to assess the risk of BSE outbreak in each country, the Office International des Epizooties (OIE) and EU have respectively established criteria, where OIE has set 5 levels and EU has set 4 levels. The Scientific Steering Committee (SSC) of the European Commission conducted a Geographical BSE Risk(GBR) assessment for 64 nations, such as the United States, etc., as of April 29, 2003. However, as of July 1, 2005, the duty of GBR assessment is expected to be transferred to a newly established body called EFSA (European Food Safety Authority, located in Parma, Italy). As Korea has not undergone a GBR assessment up to now, this study analyzed the risk of BSE outbreak in Korea by reviewing BSE prevention measures, etc., that have been put in place. This study shall be a barometer for estimating the GBR assessment level of Korea. 相似文献
59.
Combined Campylobacter jejuni and Campylobacter coli Rapid Testing and Molecular Epidemiology in Conventional Broiler Flocks 下载免费PDF全文
G. Schallegger S. Muri‐Klinger K. Brugger C. Lindhardt L. John M. Glatzl M. Wagner B. Stessl 《Zoonoses and public health》2016,63(8):588-599
Campylobacter spp. are important causes of bacterial zoonosis, most often transmitted by contaminated poultry meat. From an epidemiological and risk assessment perspective, further knowledge should be obtained on Campylobacter prevalence and genotype distribution in primary production. Consequently, 15 Austrian broiler flocks were surveyed in summer for their thermophilic Campylobacter spp. contamination status. Chicken droppings, dust and drinking water samples were collected from each flock at three separate sampling periods. Isolates were confirmed by PCR and subtyped. We also compared three alternative methods (culture‐based enrichment in Bolton broth, culture‐independent real‐time PCR and a lateral‐flow test) for their applicability in chicken droppings. Twelve flocks were found to be positive for thermophilic Campylobacter spp. during the entire sampling period. Seven flocks (46.6%) were contaminated with both, C. jejuni and C. coli, five flocks harboured solely one species. We observed to a majority flock‐specific C. jejuni and C. coli genotypes, which dominated the respective flock. Flocks within a distance <2 km shared the same C. jejuni genotypes indicating a cross‐contamination event via the environment or personnel vectors. Multilocus sequence typing (MLST) of C. jejuni revealed that the majority of isolates were assigned to globally distributed clonal complexes or had a strong link to the human interface (CC ST‐446 and ST4373). The combination of techniques poses an advantage over risk assessment studies based on cultures alone, as, in the case of Campylobacter, occurrence of a high variety of genotypes might be present among a broiler flock. We suggest applying the lateral‐flow test under field conditions to identify ‘high‐shedding’ broiler flocks at the farm level. Consequently, poultry farmers and veterinarians could improve hygiene measurements and direct sanitation activities, especially during the thinning period. Ultimately, real‐time PCR could be applied to quantify Campylobacter spp. directly from chicken droppings and avoid non‐interpretable results achieved by culture‐dependent methods. 相似文献
60.
A 10-year-old female Eurasian river otter (Lutra lutra) died after prolonged anorexia and weight loss in the Seoul Grand Park Zoo, Seoul, Republic of Korea. On necropsy, the liver was found to be swollen and friable with 1 lobe enlarged and necrotic. The other organs showed no significant alterations except for mild atrophy of the right kidney. Microscopically, there was multifocal hepatic necrosis. The hepatocytes around the necrotic areas were swollen and contained large basophilic intranuclear inclusions. Periportal infiltration by plasma cells and lymphocytes was also evident. Transmission electron microscopy revealed characteristic hexagonal virus particles sized approximately 70 nm in diameter in the nuclei of the hepatocytes, which were consistent with an adenovirus. Polymerase chain reaction of the formalin-fixed, paraffin-embedded liver sections was used to determine whether the virus was either the canine adenovirus type 1 (CAV-1), canine adenovirus type 2 (CAV-2), or some other viral agent. The results of these tests showed that the virus was CAV-1. To our knowledge, this is the first report on a CAV-1 infection in an otter. 相似文献