全文获取类型
收费全文 | 742篇 |
免费 | 11篇 |
专业分类
林业 | 45篇 |
农学 | 32篇 |
基础科学 | 2篇 |
99篇 | |
综合类 | 37篇 |
农作物 | 22篇 |
水产渔业 | 77篇 |
畜牧兽医 | 400篇 |
园艺 | 8篇 |
植物保护 | 31篇 |
出版年
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 15篇 |
2019年 | 7篇 |
2018年 | 18篇 |
2017年 | 8篇 |
2016年 | 14篇 |
2015年 | 8篇 |
2014年 | 19篇 |
2013年 | 67篇 |
2012年 | 31篇 |
2011年 | 21篇 |
2010年 | 13篇 |
2009年 | 20篇 |
2008年 | 40篇 |
2007年 | 44篇 |
2006年 | 38篇 |
2005年 | 32篇 |
2004年 | 30篇 |
2003年 | 33篇 |
2002年 | 24篇 |
2001年 | 32篇 |
2000年 | 24篇 |
1999年 | 21篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1994年 | 6篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1973年 | 6篇 |
1972年 | 8篇 |
1971年 | 2篇 |
1970年 | 3篇 |
1965年 | 6篇 |
1964年 | 3篇 |
排序方式: 共有753条查询结果,搜索用时 15 毫秒
71.
72.
Jezie A. Acorda DVM MAgr Haruo Yamada DVM DVSc Seyed Mehdi Ghamsari DVM 《Veterinary radiology & ultrasound》1994,35(2):120-123
Ultrasonography of the liver of 49 Holstein-Friesian cows was performed, liver specimens were taken, examined microscopically and the fatty occupying rate (FOR) was calculated. Echoes from the hepatic B-mode ultrasonograms were quantified as histogram mean (Emean) and histogram mode (Emode) of echo amplitudes within various areas at a depth of 1–9 cm from the hepatic surface. Of the 49 animals, 26 had a normal liver and 23 had fatty infiltration of the liver, diagnosed through histopathological examination. Fatty occupying rate ranged from 1.7 to 64.5%, with 11 animals having 1–15% FOR (mild fatty infiltration), 6 having 15.1–30% FOR (moderate fatty infiltration) and 6 having > 30% FOR (severe fatty infiltration). At 1 cm, severe fatty infiltration had higher Emean and Emode than normal liver (p < 0.05). At 7 cm and 9 cm, moderate and severe fatty infiltration had lower Emeans and Emodes than normal liver (p < 0.001). The results suggest that digital analysis of hepatic ultrasonogram can be useful in the evaluation of the degree of fatty infiltration of the liver in dairy cattle. 相似文献
73.
74.
75.
76.
77.
Morphological Study of the Surface Structure of the Omasal Laminae in Cattle, Sheep and Goats 总被引:1,自引:0,他引:1
Y. Yamamoto N. Kitamura J. Yamada A. Andrén T. Yamashita 《Anatomia, histologia, embryologia》1994,23(2):166-176
The mucosal relief of the omasum in cattle, sheep and goats was examined by the naked eye, stereoscopic microscope and scanning electron microscope. The mucosal relief of the omasum showed wide variations both between and within these species. Omasal papillae on the laminae varied highly in shape, i. e. conical, rounded, claw-like, wart-like, finger-like etc. They decreased gradually in size from the oral to the aboral region of the omasal lamina. Ridge-like structures and linear arrangements of the papillae were also seen on the omasal laminae of cattle and sheep. Many grooves and folds were found on the lateral surface of the omasal papillae in adult cattle and on the inter-papillar surface of the laminae of all three species. The mucosal relief of the omasum in cattle seemed to be more well-developed than those of sheep and goats. Dietary effects on the omasal mucosa were also discussed. 相似文献
78.
79.
80.