全文获取类型
收费全文 | 465篇 |
免费 | 57篇 |
专业分类
林业 | 16篇 |
农学 | 5篇 |
42篇 | |
综合类 | 78篇 |
农作物 | 14篇 |
水产渔业 | 28篇 |
畜牧兽医 | 310篇 |
园艺 | 15篇 |
植物保护 | 14篇 |
出版年
2021年 | 6篇 |
2020年 | 12篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 13篇 |
2016年 | 7篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 26篇 |
2012年 | 22篇 |
2011年 | 19篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 23篇 |
2007年 | 23篇 |
2006年 | 22篇 |
2005年 | 21篇 |
2004年 | 23篇 |
2003年 | 24篇 |
2002年 | 13篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 13篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1974年 | 7篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1970年 | 4篇 |
1969年 | 6篇 |
1968年 | 4篇 |
1967年 | 5篇 |
1966年 | 6篇 |
1962年 | 3篇 |
1960年 | 4篇 |
1928年 | 3篇 |
排序方式: 共有522条查询结果,搜索用时 31 毫秒
1.
Stuart Fraser Mireia Gomez‐Gallego Judy Gardner Lindsay S. Bulman Sandra Denman Nari M. Williams 《Forest Pathology》2020,50(2)
Phytophthora pluvialis and Phytophthora kernoviae are the causal agents of important needle diseases on Pinus radiata in New Zealand. Little is known about the epidemiology of the diseases, making the development of control strategies challenging. To investigate the seasonality and climatic drivers of sporulation, inoculum traps, consisting of pine fascicles floating on water in plastic containers, were exchanged fortnightly at five sites in P. radiata plantations between February 2012 and December 2014. Sections of needle baits were plated onto selective media and growth of Phytophthora pluvialis and P. kernoviae recorded. To explore the generalizability of these data, they were compared to detection data for both pathogens from the New Zealand Forest Health Database (NZFHDB). Further, equivalent analyses on infection of Rhododendron ponticum by P. kernoviae in Cornwall, UK allowed the comparison of the epidemiology of P. kernoviae across different host systems and environments. In New Zealand, inoculum of P. pluvialis and P. kernoviae was detected between January–December and March–November, respectively. Inoculum of both species peaked in abundance in late winter. The probability of detecting P. pluvialis and P. kernoviae was greater at lower temperatures, while the probability of detecting P. pluvialis also increased during periods of wet weather. Similar patterns were observed in NZFHDB data. However, the seasonal pattern of infection by P. kernoviae in the UK was the opposite of that seen for sporulation in New Zealand. Phytophthora kernoviae was likely limited by warmer and drier summers in New Zealand, but by colder winter weather in the UK. These results emphasize the importance of considering both environmental drivers and thresholds in improving our understanding of pathogen epidemiology. 相似文献
2.
3.
4.
5.
6.
7.
8.
J. Fraser McConnell BVM&S Laurent S. Garosi DVM 《Veterinary radiology & ultrasound》2004,45(4):327-330
Intervertebral disk extrusion is rarely reported in the cat. In this case, the clinical, radiologic, and magnetic resonance imaging findings of an acute intramedullary intervertebral disk extrusion in a 5-year-old domestic shorthaired cat are described. Radiographically, there was mineralized disk material within the vertebral canal. On magnetic resonance images, the disk material was found to be within the spinal cord. A linear disk trail extending from the disk space into the spinal cord may be specific for intramedullary disk extrusion. 相似文献
9.
P Zhang N Fegan I Fraser P Duffy R E Bowles A Gordon P J Ketterer W Shinwari P J Blackall 《Journal of veterinary diagnostic investigation》2004,16(5):458-460
Two outbreaks of fowl cholera on a multiage free-range egg farm were investigated. The outbreaks occurred in 1994 and 2002. A total of 22 strains of Pasteurella multocida were available for study, 11 from the 1994 outbreak and 11 from the 2002 outbreak. Lesions typical of acute fowl cholera were seen in the 1994 outbreak, whereas both acute and chronic fowl cholera occurred in the 2002 outbreak. The isolates were examined in an extended phenotypic typing methodology, by a P. multocida-specific polymerase chain reaction (PCR), by the Heddleston somatic serotyping scheme, and by restriction endonuclease analysis (REA) typing using the enzyme HpaII. All 22 strains had the same phenotypic properties, all were confirmed as P. multocida by PCR, all were Heddleston serovar 4, and all had the same REA pattern. The results indicate that these 2 outbreaks were caused by the same clone of P. multocida--despite the 8-year time period between the outbreaks. 相似文献
10.
In May 2019, 96 cattle died from Pimelea toxicity in a period of 19 days after potential exposure, with the first deaths occurring within 5 days. After examining the circumstances, we suspect that several factors contributed to the deaths. These included that recently purchased stock and transported had access to flooded land containing Pimelea elongata. This weed species contains simplexin and 18 other compounds. Roots, flowers and seeds are significantly more toxic than the stem, branches and leaves. We suspect that thirsty and hungry stock consumed seed and roots from flooded pastures and consumed lethal doses of simplexin. Blood tests were not good indicators of the conditions. Management strategies are suggested. 相似文献