全文获取类型
收费全文 | 252篇 |
免费 | 6篇 |
专业分类
林业 | 59篇 |
农学 | 5篇 |
基础科学 | 3篇 |
64篇 | |
综合类 | 22篇 |
农作物 | 6篇 |
水产渔业 | 8篇 |
畜牧兽医 | 68篇 |
园艺 | 5篇 |
植物保护 | 18篇 |
出版年
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 2篇 |
2014年 | 11篇 |
2013年 | 8篇 |
2012年 | 11篇 |
2011年 | 18篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 18篇 |
2007年 | 10篇 |
2006年 | 10篇 |
2005年 | 19篇 |
2004年 | 16篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1965年 | 1篇 |
1958年 | 1篇 |
1954年 | 1篇 |
1940年 | 1篇 |
1938年 | 1篇 |
1937年 | 1篇 |
1936年 | 1篇 |
1930年 | 2篇 |
1928年 | 6篇 |
排序方式: 共有258条查询结果,搜索用时 15 毫秒
1.
J. Cabaret H. M. Baudet J. Devos J. Hubert J. Cortet C. Sauv 《Veterinary parasitology》1995,60(3-4):331-337
Multispecific resistance to benzimidazoles was studied in three selected farms. These farms had bred dairy goats for more than 15 years. The helminths were introduced with the goats at the establishment of the farms which afterwards remained isolated. Nematode resistance could then be related to their own management practices. Faecal egg count tests and egg hatch assays were performed to assess intensity of resistance. The generic (infective larvae in faecal cultures) and specific richness (adult worms) were assessed. The resistant species were Trichostrongylus colubriformis, Teladorsagia circumcincta, Haemonchus contortus and Oesophagostomum venulosum. Faecal egg count reduction tests and egg-hatch assays did not match exactly. Faecal larval counts after treatments gave a distorted picture of multispecific resistance: Haemonchus and Oesophagostomum were very largely over represented. The number of species found in the three farms was relatively low compared with other reports in goat farms of the area. This reduction of diversity might also be due in part to characteristics of breeding management and history (use of permanent pasture and introduction of goats at the establishment of farm). 相似文献
2.
3.
Karl Hubert Heil 《Journal of pest science》1936,12(5):49-52
Ohne Zusammenfassung
Mit 3 Abbildungen 相似文献
4.
5.
Hubert Freiherr von Rechmann 《Forstwissenschaftliches Centralblatt》1928,50(21):705-725
Ohne Zusammenfassung 相似文献
6.
7.
8.
Competition and interactions among stripe rust pathotypes in wheat-cultivar mixtures 总被引:1,自引:0,他引:1
A series of experiments was conducted with wheat stripe rust to analyse competition between simple and complex pathotypes in host mixtures. Two different pathotype combinations were tested, with different host components. Each combination included a complex (able to infect two host components) and two simple pathotypes. For one of the combinations, induced resistance was tested in a separate experiment as a possible interaction among pathotypes. Disease severity and pathotype frequencies were measured three times during the epidemic, on each host component grown in pure stands and in mixtures. In one of the experiments, pathotype frequencies were also measured within secondary foci. One of the complex pathotypes appeared to have a low fitness on one of the host components and did not significantly increase in frequency in host mixtures relative to pure stands. The average frequency of the other complex pathotype increased during the first epidemic cycles, but remained stable afterwards, below expected values. The results suggest that the development of complex pathotypes in host mixtures may be influenced by differential aggressiveness on the host components, by induced resistance and by random effects resulting from the formation of disease foci, and depends on pathogen autoinfection rate and dispersal mechanisms. 相似文献
9.
Ohne Zusammenfassung 相似文献
10.
Ohne Zusammenfassung 相似文献