全文获取类型
收费全文 | 271篇 |
免费 | 24篇 |
专业分类
林业 | 33篇 |
农学 | 9篇 |
44篇 | |
综合类 | 11篇 |
农作物 | 7篇 |
水产渔业 | 9篇 |
畜牧兽医 | 161篇 |
园艺 | 1篇 |
植物保护 | 20篇 |
出版年
2023年 | 2篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 15篇 |
2013年 | 19篇 |
2012年 | 16篇 |
2011年 | 14篇 |
2010年 | 5篇 |
2009年 | 11篇 |
2008年 | 14篇 |
2007年 | 18篇 |
2006年 | 23篇 |
2005年 | 12篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1990年 | 4篇 |
1987年 | 5篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1969年 | 4篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1964年 | 2篇 |
1906年 | 1篇 |
1905年 | 1篇 |
1902年 | 2篇 |
排序方式: 共有295条查询结果,搜索用时 15 毫秒
291.
ER Weeks Y Tian JS Urbach K Ide HL Swinney M Ghil 《Science (New York, N.Y.)》1997,278(5343):1598-1601
The mid-latitude atmosphere is dominated by westerly, nearly zonal flow. Occasionally, this flow is deflected poleward by blocking anticyclones that persist for 10 days or longer. Experiments in a rotating annulus used radial pumping to generate a zonal jet under the action of the Coriolis force. In the presence of two symmetric ridges at the bottom of the annulus, the resulting flows were nearly zonal at high forcing or blocked at low forcing. Intermittent switching between blocked and zonal patterns occurs because of the jet's interaction with the topography. These results shed further light on previous atmospheric observations and numerical simulations. 相似文献
292.
Determination of seven organosulfur compounds in garlic by high-performance liquid chromatography 总被引:2,自引:0,他引:2
Ichikawa M Ide N Yoshida J Yamaguchi H Ono K 《Journal of agricultural and food chemistry》2006,54(5):1535-1540
The properties of garlic (Allium sativum L.) are attributed to organosulfur compounds. Although these compounds change during cultivation and storage, there is no report of their simultaneous analysis. Here, a newly developed analytical method with a rapid and simple sample preparation to determine four sulfoxides and three gamma-glutamyl peptides in garlic is reported. All garlic samples were simply extracted with 90% methanol solution containing 0.01 N hydrochloric acid and prepared for analysis. Alliin, isoalliin, methiin, cycloalliin, and gamma-l-glutamyl-S-methyl-l-cysteine were determined by normal-phase HPLC using an aminopropyl-bonded column. gamma-l-Glutamyl-S-(2-propenyl)-l-cysteine and gamma-l-glutamyl-S-(trans-1-propenyl)-l-cysteine were separated on an octadecylsilane column. The overall recoveries were 97.1-102.3%, and the relative standard deviation values of intra- and interday precision were lower than 2.6 and 4.6%, respectively. This newly developed method offers some advantages over the currently accepted techniques including specificity, speed, and ease of use and would be useful for chemical and biological studies of garlic and its preparations. 相似文献
293.
294.
Acer mono Maxim. is one of the major components of cool temperate forests in Japan. Some of its many varieties are distributed sympatrically. Because of its great variability, the intraspecific taxonomy and nomenclature of the species are controversial. To understand the genetic relationships among these varieties and whether hybridization or introgression occurred among the sympatric varieties, we studied the genetic relationships among sympatric varieties of A. mono in the Chichibu Mountains (A. mono var. ambiguum, A. mono var. connivens, A. mono var. marmoratum) and Central Hokkaido (A. mono var. mayrii and A. mono var. glabrum) in Japan. Our results showed that varieties in Chichibu are genetically close, suggesting that hybridization or introgression might occur between these varieties, which could explain the higher genetic diversity of varieties in Chichibu than in Hokkaido. In contrast to the close relationships between the varieties in Chichibu, varieties in Hokkaido seemed relatively separated from each other; indeed, there may be reproductive isolation between the two varieties. The results provide new insight for the taxonomy of the varieties of A. mono, especially the sympatric varieties, in Japan. 相似文献
295.
Sakai K Ueno Y Ueda S Yada K Fukushi S Saijo M Kurane I Mutoh K Yoshioka K Nakamura M Takehara K Morikawa S Mizutani T 《Veterinary microbiology》2009,134(3-4):227-232
An orthoreovirus was isolated from an Ostrich (Struthio camelus) and rapidly identified as orthoreovirus by the rapid determination of viral RNA sequences (RDV) system and electron microscopy. Phylogenetic analysis of the sigma A protein indicated that the isolate belonged to avian species and was closely related to chicken orthoreovirus strain 138. The results of the present study indicated that an ostrich orthoreovirus is slight different from other chicken orthoreoviruses and provided evidence of diversity among avian orthoreoviruses. To our knowledge, this is the first genetic report of an orthoreovirus isolated from an ostrich. 相似文献