全文获取类型
收费全文 | 496篇 |
免费 | 51篇 |
专业分类
林业 | 27篇 |
农学 | 3篇 |
基础科学 | 1篇 |
32篇 | |
综合类 | 64篇 |
农作物 | 6篇 |
水产渔业 | 45篇 |
畜牧兽医 | 342篇 |
园艺 | 4篇 |
植物保护 | 23篇 |
出版年
2023年 | 7篇 |
2021年 | 7篇 |
2020年 | 17篇 |
2019年 | 14篇 |
2018年 | 14篇 |
2017年 | 16篇 |
2016年 | 13篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 27篇 |
2012年 | 20篇 |
2011年 | 18篇 |
2010年 | 17篇 |
2009年 | 13篇 |
2008年 | 23篇 |
2007年 | 12篇 |
2006年 | 17篇 |
2005年 | 19篇 |
2004年 | 14篇 |
2003年 | 19篇 |
2002年 | 16篇 |
2001年 | 22篇 |
2000年 | 9篇 |
1999年 | 10篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1985年 | 5篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 11篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1971年 | 3篇 |
1970年 | 5篇 |
1969年 | 3篇 |
1967年 | 4篇 |
1958年 | 3篇 |
排序方式: 共有547条查询结果,搜索用时 15 毫秒
151.
D B Griffin J W Savell J B Morgan R P Garrett H R Cross 《Journal of animal science》1992,70(8):2411-2430
One hundred beef carcasses were selected to represent the mix of cattle slaughtered across the United States. Selection criteria included breed type (60% British/continental European, 20% Bos indicus, and 20% dairy carcasses), sex class (beef and Bos indicus: 67% steers, 33% heifers; dairy: 100% steers), USDA quality grade (4% Prime, 53% Choice, and 43% Select), USDA yield grade (10% YG 1, 43% YG 2, 40% YG 3, and 7% YG 4), and carcass weight (steers: 272.2 to 385.6 kg, heifers: 226.8 to 340.2 kg). One side of each carcass was fabricated into boneless subprimals and minor cuts following Institutional Meat Purchase Specifications. After fabrication, subprimals were trimmed progressively of fat in .64-cm increments beginning with a maximum of 2.54 cm and ending with .64 cm. Linear regression models were developed for each individual cut, including fabrication byproduct items (bone, fat trim) to estimate the percentage yield of those cuts reported by USDA Market News. Strip loin, top sirloin butt, and gooseneck rounds from heifers tended to have a higher percentage yield at the same USDA yield grade than the same cuts from steers, possibly resulting from increased fat deposition on heifers. Percentage of fat trimmed from dairy steers was 2 to 3% lower than that from other sex-class/carcass types; however, due to increased percentage of bone and less muscle, dairy steers were lower-yielding. Fat trimmed from carcasses ranged from 7.9 to 15.6% as the maximum trim level decreased from 2.54 to .64 cm. 相似文献
152.
153.
A clinical trial of a topical preparation of miconazole, polymyxin and prednisolone in the treatment of otitis externa in dogs 总被引:3,自引:0,他引:3
A topical preparation containing miconazole, polymyxin and prednisolone was shown to be more effective in the treatment of otitis externa in 167 dogs than 2 other ear preparations containing antibiotics, an antimycotic and a corticosteroid. With miconazole, polymyxin and prednisolone, the recurrence rate was 26.7% compared with 72.6% and 54.3% when the other products were used. The mean duration of treatment required to achieve resolution of clinical signs was 9.6 days, compared with 12.2 days and 13.0 days and no cases failed to respond to treatment, compared with 17.7% and 14.3%. Malassezia canis alone (71%) or in association with bacteria (18%) was recovered from 44 of 49 ears cultured. 相似文献
154.
155.
156.
Closantel has been shown to have high anthelminitic activity against the larval stage of Taenia pisiformis at a dose rate of 40 mg/kg per os or 20 mg/kg by intra-muscular injection. The drug does not appear to have significant activity against the cysticercus stage in the peritoneal cavity. 相似文献
157.
158.
159.
160.
Fetal activity and mobility and changes in diameter of the allantoic fluid compartment in the uterine horns were studied in mares between days 69 and 81 of pregnancy by use of transrectal ultrasonography (n = 12) and transcervical videoendoscopy (n = 8). The insertion tube of the videoendoscope was positioned within the allantoic sac to permit viewing of the fetus and entrance to each uterine horn. Each uterine horn was divided ultrasonographically into 3 segments of equal length, and the horns were designated on the basis of side of umbilical attachment (cord vs noncord horns). The diameter of the allantoic fluid compartment in the cornual segments increased (P less than 0.05) over the cranial (18.6 +/- 1.9 mm), middle (35.6 +/- 2.9 mm), and caudal (51.7 +/- 4.4 mm) segments, but differences between cord and noncord horns were not evident. Dynamic changes in diameter of the allantoic fluid compartment in cornual segments (ultrasonography) and at the entrance to each uterine horn (videoendoscopy) were detected (no significant difference between methods). During continuous videoendoscopic viewing (17 to 60 min/mare), extreme changes in allantoic fluid compartment diameter (76 to 100% of maximum to 0 to 25% of maximum or vice-versa) occurred an equivalent of 2.6 times/h/horn entrance; changes had an average duration of 3.4 minutes. A change from 100% (maximal diameter) to 0% (no visible lumen) or vice-versa occurred an equivalent of 1.3 times/h/horn entrance. Sometimes the uterine wall was so closely constricted++ around the fetal-amniotic unit that no intervening allantoic fluid was ultrasonographically detectable whereas at other times the uterus in the same location was widely dilated.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献