全文获取类型
| 收费全文 | 104339篇 |
| 免费 | 4699篇 |
| 国内免费 | 99篇 |
专业分类
| 林业 | 7488篇 |
| 农学 | 3696篇 |
| 基础科学 | 681篇 |
| 13573篇 | |
| 综合类 | 17719篇 |
| 农作物 | 5742篇 |
| 水产渔业 | 5839篇 |
| 畜牧兽医 | 45367篇 |
| 园艺 | 2016篇 |
| 植物保护 | 7016篇 |
出版年
| 2019年 | 859篇 |
| 2018年 | 4106篇 |
| 2017年 | 4262篇 |
| 2016年 | 2432篇 |
| 2015年 | 1099篇 |
| 2014年 | 1366篇 |
| 2013年 | 2911篇 |
| 2012年 | 3324篇 |
| 2011年 | 5444篇 |
| 2010年 | 4365篇 |
| 2009年 | 3668篇 |
| 2008年 | 4625篇 |
| 2007年 | 4883篇 |
| 2006年 | 2743篇 |
| 2005年 | 2695篇 |
| 2004年 | 2520篇 |
| 2003年 | 2712篇 |
| 2002年 | 2343篇 |
| 2001年 | 2470篇 |
| 2000年 | 2560篇 |
| 1999年 | 1953篇 |
| 1998年 | 793篇 |
| 1997年 | 772篇 |
| 1996年 | 766篇 |
| 1995年 | 879篇 |
| 1994年 | 752篇 |
| 1993年 | 816篇 |
| 1992年 | 1639篇 |
| 1991年 | 1796篇 |
| 1990年 | 1690篇 |
| 1989年 | 1696篇 |
| 1988年 | 1528篇 |
| 1987年 | 1564篇 |
| 1986年 | 1635篇 |
| 1985年 | 1591篇 |
| 1984年 | 1228篇 |
| 1983年 | 1095篇 |
| 1979年 | 1171篇 |
| 1978年 | 926篇 |
| 1977年 | 804篇 |
| 1975年 | 802篇 |
| 1974年 | 1043篇 |
| 1973年 | 1040篇 |
| 1972年 | 1051篇 |
| 1971年 | 999篇 |
| 1970年 | 993篇 |
| 1969年 | 913篇 |
| 1968年 | 838篇 |
| 1967年 | 811篇 |
| 1966年 | 736篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
31.
32.
H E Kennedy S J McCullough D Graham J Cassidy F E Malone W A Ellis 《Journal of veterinary diagnostic investigation》2001,13(1):30-35
Two serological tests (indirect immunofluorescence and enzyme-linked immunosorbent assay) were developed for the detection of fetal antibody to Chlamydia psittaci. Fetal blood and thoracic fluid from 126 field cases of suspected ovine chlamydial abortion were examined using both tests. Placenta and fetal tissues (lung, liver, and kidney) from the same animals were also examined by the following conventional diagnostic methods: isolation in McCoy cells, detection of chlamydial lipopolysaccharide (LPS), modified Ziehl-Nielsen staining, and direct fluorescent antibody staining of chlamydia in frozen cryostat sections. Seventy cases were positive by fetal serology, and of these, 68 were also positive by isolation and/or LPS detection. The remaining 56 cases had negative fetal serology, and of these, 39 were positive by isolation and/or LPS detection. Results indicate that fetal serology, although less sensitive than either isolation in McCoy cells or detection of chlamydial LPS antigen, may be of particular use when placenta is not available. 相似文献
33.
Dogs vaccinated with a Leptospira interrogans vaccine containing serogroups Canicola and Icterohaemorrhagiae and prepared from cultures grown in a protein-free medium resisted challenge with heterologous representatives of these serogroups. In contrast, control dogs were pyrexic and leptospires were isolated from the blood for nine days following Canicola challenge and six days after Icterohaemorrhagiae challenge. Leptospires were isolated from the urine of controls throughout the post challenge period and from kidneys at post mortem examination of six out of six and four out of six Canicola and Icterohaemorrhagiae challenged controls, respectively. There have been no reports of hypersensitivity reactions to this vaccine since its introduction in 1980. 相似文献
34.
35.
Wodsedalek JE 《Science (New York, N.Y.)》1917,46(1189):366-367
36.
37.
38.
39.