全文获取类型
| 收费全文 | 155940篇 |
| 免费 | 8017篇 |
| 国内免费 | 657篇 |
专业分类
| 林业 | 9521篇 |
| 农学 | 5867篇 |
| 基础科学 | 1222篇 |
| 20274篇 | |
| 综合类 | 26945篇 |
| 农作物 | 7236篇 |
| 水产渔业 | 8458篇 |
| 畜牧兽医 | 71634篇 |
| 园艺 | 2865篇 |
| 植物保护 | 10592篇 |
出版年
| 2019年 | 1406篇 |
| 2018年 | 4817篇 |
| 2017年 | 5129篇 |
| 2016年 | 3304篇 |
| 2015年 | 2040篇 |
| 2014年 | 2322篇 |
| 2013年 | 5033篇 |
| 2012年 | 5140篇 |
| 2011年 | 7538篇 |
| 2010年 | 5886篇 |
| 2009年 | 5014篇 |
| 2008年 | 6577篇 |
| 2007年 | 6653篇 |
| 2006年 | 4448篇 |
| 2005年 | 4287篇 |
| 2004年 | 4068篇 |
| 2003年 | 4208篇 |
| 2002年 | 3853篇 |
| 2001年 | 4280篇 |
| 2000年 | 4339篇 |
| 1999年 | 3426篇 |
| 1998年 | 1534篇 |
| 1997年 | 1384篇 |
| 1996年 | 1311篇 |
| 1995年 | 1448篇 |
| 1994年 | 1364篇 |
| 1993年 | 1311篇 |
| 1992年 | 2762篇 |
| 1991年 | 2932篇 |
| 1990年 | 2970篇 |
| 1989年 | 2815篇 |
| 1988年 | 2646篇 |
| 1987年 | 2614篇 |
| 1986年 | 2669篇 |
| 1985年 | 2488篇 |
| 1984年 | 2116篇 |
| 1983年 | 1879篇 |
| 1982年 | 1207篇 |
| 1979年 | 1882篇 |
| 1978年 | 1508篇 |
| 1977年 | 1316篇 |
| 1976年 | 1290篇 |
| 1975年 | 1360篇 |
| 1974年 | 1668篇 |
| 1973年 | 1686篇 |
| 1972年 | 1632篇 |
| 1971年 | 1522篇 |
| 1970年 | 1469篇 |
| 1969年 | 1450篇 |
| 1967年 | 1262篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
81.
82.
83.
84.
85.
86.
87.
88.
C Richardson W P Taylor S Terlecki E P Gibbs 《American journal of veterinary research》1985,46(9):1912-1922
Twenty-four ewes were inoculated with 1 of 2 strains of bluetongue virus type 4 at 40, 60, or 80 days of gestation. Two ewes aborted, 2 ewes died, and 1 was killed during the experiment, but their fetuses were recovered. At term, 2 mummified fetuses, 4 dead lambs, and 17 clinically healthy lambs were produced by 12 sheep, and the remaining 7 sheep were barren. Porencephaly and cerebellar dysgenesis were found in term lambs born to sheep inoculated at 40 and 60 days of gestation. Radiographic examination of 12 fetuses showed developmental ages far less than their chronologic age; 8 fetuses had skeletal growth-retardation lines, which were also observed in the dead lambs. A systemic lymphoreticular hyperplasia was observed in the dead lambs and in all lambs at 12 weeks of age; in 4 of the latter, granulomatous reactions were present in the liver and kidney. Lungs of the full-term lambs were reduced in weight and showed poor alveolar development and mononuclear cell infiltration, which persisted in the 12-week-old lambs. It was concluded that bluetongue virus is capable of causing not only gross abnormalities of the CNS, but also generalized growth retardation and fetal lymphoreticular hyperplasia. 相似文献
89.
Antigens in the extracellular protein (ECP) complexes of Bacteroides nodosus, isolated from sheep with either benign or virulent footrot, were studied by immunoelectrophoresis (IEP). Rabbit antisera against ECP from virulent and benign strains, were used in homologous and heterologous crossed IEP. Four precipitin peaks unique to the virulent strain, and five peaks unique to the benign strain were identified. In an attempt to characterize the different antigens in ECP, rabbit antisera were raised against an outer membrane protein (OMP, mol. wt. 35 000 daltons), pili and various proteases of virulent and benign strains of B. nodosus. No precipitin band was observed when ECP from both B. nodosus strains were reacted against anti-OMP and anti-pilus antisera. However, single precipitin bands unique to one protease from the benign strain and one protease from the virulent strain were identified. The results suggest that specific antigens other than proteases or pili are important in determining whether a B. nodosus isolate is virulent or benign. 相似文献
90.
L Klein 《Veterinary Clinics of North America: Equine Practice》1985,1(1):77-89
A brief discussion of those aspects of neonatal physiology that pertain to anesthetic risk and selection of anesthetic techniques is followed by discussion of suggested techniques for anesthetic management in healthy foals. Preoperative preparation and management of foals with selected serious surgical conditions are also considered. 相似文献