全文获取类型
收费全文 | 752篇 |
免费 | 68篇 |
专业分类
林业 | 14篇 |
农学 | 10篇 |
基础科学 | 2篇 |
84篇 | |
综合类 | 162篇 |
农作物 | 12篇 |
水产渔业 | 56篇 |
畜牧兽医 | 415篇 |
园艺 | 11篇 |
植物保护 | 54篇 |
出版年
2023年 | 9篇 |
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 4篇 |
2018年 | 13篇 |
2017年 | 10篇 |
2016年 | 22篇 |
2015年 | 18篇 |
2014年 | 17篇 |
2013年 | 33篇 |
2012年 | 29篇 |
2011年 | 32篇 |
2010年 | 32篇 |
2009年 | 10篇 |
2008年 | 20篇 |
2007年 | 35篇 |
2006年 | 34篇 |
2005年 | 24篇 |
2004年 | 38篇 |
2003年 | 24篇 |
2002年 | 18篇 |
2001年 | 19篇 |
2000年 | 25篇 |
1999年 | 21篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 13篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 19篇 |
1991年 | 11篇 |
1990年 | 21篇 |
1989年 | 9篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 18篇 |
1985年 | 14篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 8篇 |
1972年 | 12篇 |
1971年 | 14篇 |
1970年 | 10篇 |
1969年 | 5篇 |
1966年 | 6篇 |
排序方式: 共有820条查询结果,搜索用时 15 毫秒
21.
Karimuribo ED Fitzpatrick JL Bell CE Swai ES Kambarage DM Ogden NH Bryant MJ French NP 《Preventive veterinary medicine》2006,74(1):84-98
In a cross-sectional study of 400 randomly selected smallholder dairy farms in the Tanga and Iringa regions of Tanzania, 14.2% (95% confidence interval (CI)=11.6-17.3) of cows had developed clinical mastitis during the previous year. The point prevalence of subclinical mastitis, defined as a quarter positive by the California Mastitis Test (CMT) or by bacteriological culture, was 46.2% (95% CI=43.6-48.8) and 24.3% (95% CI=22.2-26.6), respectively. In a longitudinal disease study in Iringa, the incidence of clinical mastitis was 31.7 cases per 100 cow-years. A randomised intervention trial indicated that intramammary antibiotics significantly reduced the proportion of bacteriologically positive quarters in the short-term (14 days post-infusion) but teat dipping had no detectable effect on bacteriological infection and CMT positive quarters. Other risk and protective factors were identified from both the cross-sectional and longitudinal included animals with Boran breeding (odds ratio (OR)=3.40, 95% CI=1.00-11.57, P<0.05 for clinical mastitis, and OR=3.51, 95% CI=1.29-9.55, P<0.01 for a CMT positive quarter), while the practice of residual calf suckling was protective for a bacteriologically positive quarter (OR=0.63, 95% CI=0.48-0.81, P相似文献
22.
23.
24.
A E Schultze I Sonea T G Bell 《Journal of the American Veterinary Medical Association》1988,193(4):477-480
Although primary malignant pulmonary neoplasia of horses is rarely encountered, this diagnosis was confirmed in 2 horses on the basis of necropsy and histopathologic findings. One horse, with cystic mucinous adenocarcinoma, had respiratory tract and neurologic signs directly attributable to the neoplasm, and a tentative antemortem diagnosis of pulmonary neoplasia was made. The other horse, with anaplastic bronchogenic carcinoma, did not have clinical signs of pulmonary neoplasia. 相似文献
25.
A 2-year-old Standardbred gelding was referred for a mass on the palmaromedial right front pastern which was accompanied by progressively worsening lameness. The mass was firm to palpation and covered by normal skin. Ultrasonographically, a smooth encapsulated mass was present, medial to the flexor tendons and palmar to the neurovascular bundle. Because of a poor prognosis for future athletic performance without surgical or chemotherapeutic intervention and economic constraints preventing further diagnostics and treatment, the horse was euthanised. Post-mortem magnetic resonance imaging, histopathology and immunohistochemistry revealed the mass to be a perivascular wall tumour, the first record of such a neoplasia in the horse. 相似文献
26.
27.
28.
29.
30.