全文获取类型
收费全文 | 105771篇 |
免费 | 5434篇 |
国内免费 | 52篇 |
专业分类
林业 | 4338篇 |
农学 | 3042篇 |
基础科学 | 729篇 |
11766篇 | |
综合类 | 20742篇 |
农作物 | 4301篇 |
水产渔业 | 4624篇 |
畜牧兽医 | 54380篇 |
园艺 | 1202篇 |
植物保护 | 6133篇 |
出版年
2018年 | 1207篇 |
2017年 | 1332篇 |
2016年 | 1287篇 |
2015年 | 1090篇 |
2014年 | 1267篇 |
2013年 | 3939篇 |
2012年 | 2577篇 |
2011年 | 3203篇 |
2010年 | 2083篇 |
2009年 | 2064篇 |
2008年 | 3217篇 |
2007年 | 2953篇 |
2006年 | 2810篇 |
2005年 | 2651篇 |
2004年 | 2769篇 |
2003年 | 2692篇 |
2002年 | 2630篇 |
2001年 | 3276篇 |
2000年 | 3292篇 |
1999年 | 2441篇 |
1998年 | 1073篇 |
1997年 | 1082篇 |
1995年 | 1251篇 |
1994年 | 1167篇 |
1993年 | 1125篇 |
1992年 | 2364篇 |
1991年 | 2531篇 |
1990年 | 2442篇 |
1989年 | 2494篇 |
1988年 | 2273篇 |
1987年 | 2350篇 |
1986年 | 2484篇 |
1985年 | 2394篇 |
1984年 | 1918篇 |
1983年 | 1774篇 |
1982年 | 1165篇 |
1981年 | 1123篇 |
1980年 | 1025篇 |
1979年 | 1763篇 |
1978年 | 1427篇 |
1977年 | 1146篇 |
1976年 | 1130篇 |
1975年 | 1166篇 |
1974年 | 1524篇 |
1973年 | 1610篇 |
1972年 | 1585篇 |
1971年 | 1517篇 |
1970年 | 1409篇 |
1969年 | 1263篇 |
1967年 | 1094篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
1. Automatic weighing equipment was tested on a flock of 752 roaster chickens reared on litter to 10 weeks of age.
2. Mean body weights obtained automatically were lower than those obtained manually, mainly because of birds perching on the automatic weighing perch with part of their body in contact with the floor.
3. Birds observed on the weighing perch on one day of the week were 3–5 times more likely to use the perch again on the following 2 d than expected on the basis of random perch use by flock members. These birds were also more likely to be seen in the area immediately surrounding the perch than in similar areas elsewhere in the pen. 相似文献
192.
Shapiro JL Rostkowski C Little PB Smith-Maxie L Julian RJ Van Dreumel AA 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(5):155-158
Caprine β-mannosidosis, a fatal inherited deficiency of the lysosomal enzyme β-mannosidase, was diagnosed in neonatal female Nubian crossbred twin kids from a small herd near Guelph, Ontario. The kids had been tetraplegic since birth, with whole body tremors, abnormal nystagmus and an intention tremor of the head. 相似文献
193.
194.
195.
196.
197.
Cervical intervertebral disc protrusion in two horses 总被引:2,自引:1,他引:1
Foss RR Genetzky RM Riedesel EA Graham C 《The Canadian veterinary journal. La revue veterinaire canadienne》1983,24(6):188-191
Two horses with ataxia of all four limbs were found to have cervical intervertebral disc protrusion. Severe pelvic limb ataxia, proprioceptive deficits and spasticity were present in both horses with similar but less severe signs in the thoracic limbs. Cerebrospinal fluid analysis was within normal limits. Metrizamide myelography allowed definitive diagnosis in one case when a compression of the spinal cord was demonstrated at the level of the second intervertebral space. In the second case, an intervertebral disc protrusion between cervical vertebrae 6 and 7 was found at necropsy. Fiber degeneration with poor myelin staining characterized the spinal cords histologically. 相似文献
198.
The Management of Prostaglandin-controlled Breeding Programs in Beef Cattle - A Five Year Study 下载免费PDF全文
Wenkoff M Crowe-Swords PR 《The Canadian veterinary journal. La revue veterinaire canadienne》1983,24(2):50-53
A herd of 180 beef cows was synchronized with prostaglandin and bred by artifical insemination for five successive years. Factors influencing the success or failure of estrus synchronizing programs were identified, including the management of nutrition, postpartum interval, cow age and artificial insemination technology. Specific recommendations on the management of prostaglandin-controlled breeding programs resulted in improving the pregnancy rates from 33% in year 1 to 67% in year 5. Improved management and close veterinary supervision were shown to improve the success of an estrus synchronization program. 相似文献
199.
200.
Joseph M Watson R 《The Canadian veterinary journal. La revue veterinaire canadienne》1983,24(11):366-367