全文获取类型
| 收费全文 | 179653篇 |
| 免费 | 9840篇 |
| 国内免费 | 108篇 |
专业分类
| 林业 | 7628篇 |
| 农学 | 5774篇 |
| 基础科学 | 1191篇 |
| 21980篇 | |
| 综合类 | 30438篇 |
| 农作物 | 6814篇 |
| 水产渔业 | 8706篇 |
| 畜牧兽医 | 93358篇 |
| 园艺 | 2272篇 |
| 植物保护 | 11440篇 |
出版年
| 2019年 | 1635篇 |
| 2018年 | 2541篇 |
| 2017年 | 2842篇 |
| 2016年 | 2628篇 |
| 2015年 | 2273篇 |
| 2014年 | 2763篇 |
| 2013年 | 6964篇 |
| 2012年 | 5072篇 |
| 2011年 | 6064篇 |
| 2010年 | 4076篇 |
| 2009年 | 4063篇 |
| 2008年 | 6005篇 |
| 2007年 | 5777篇 |
| 2006年 | 5486篇 |
| 2005年 | 5119篇 |
| 2004年 | 4903篇 |
| 2003年 | 5015篇 |
| 2002年 | 4647篇 |
| 2001年 | 5584篇 |
| 2000年 | 5487篇 |
| 1999年 | 4454篇 |
| 1998年 | 1832篇 |
| 1997年 | 1802篇 |
| 1996年 | 1716篇 |
| 1995年 | 1969篇 |
| 1994年 | 1720篇 |
| 1993年 | 1738篇 |
| 1992年 | 3574篇 |
| 1991年 | 3793篇 |
| 1990年 | 3830篇 |
| 1989年 | 3869篇 |
| 1988年 | 3566篇 |
| 1987年 | 3501篇 |
| 1986年 | 3534篇 |
| 1985年 | 3368篇 |
| 1984年 | 2781篇 |
| 1983年 | 2463篇 |
| 1982年 | 1691篇 |
| 1979年 | 2493篇 |
| 1978年 | 1999篇 |
| 1977年 | 1776篇 |
| 1976年 | 1715篇 |
| 1975年 | 1843篇 |
| 1974年 | 2254篇 |
| 1973年 | 2250篇 |
| 1972年 | 2275篇 |
| 1971年 | 2084篇 |
| 1970年 | 2085篇 |
| 1969年 | 1862篇 |
| 1967年 | 1680篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
991.
992.
993.
Sun M 《Science (New York, N.Y.)》1986,231(4742):1065
994.
995.
996.
997.
998.
Sun M 《Science (New York, N.Y.)》1986,233(4767):934
999.
An indirect enzyme linked immunosorbent assay (ELISA) procedure was evaluated against the serum neutralisation test (SNT) for the detection of antibodies to infectious bovine rhinotracheitis virus (bovine herpesvirus type l), using 2028 sera from 166 dairy and 172 beef cattle herds. The results showed the ELISA to give high levels of agreement with the SNT in classifying positive and negative sera (98% and 97% respectively). Such disagreements as did occur involved weakly reactive sera with SNT titres of % or less. A number of sera (n=123) with trace neutralising activity of doubtful diagnostic significance were found to give marginal reactivity with ELISA. ELISA absorbance values were found to be highly correlated with SNT titres (r=0.909) on an overall basis, though agreements were lower with individual sera. The ELISA procedure was quicker, cheaper, and detected more reactors than the SNT. It also allowed results to be obtained with a number of sera which were unsuitable for testing by SNT because of their cytotoxic nature. Analysis of ELISA results showed reactors to be present in 57% of tested sera, representing 81% of cattle herds. Reactor rates for sera and herds in the South Island, (37% and 58%), were significantly lower than for those in the North Island (64% and 88%). Antibody prevalence was also found to be significantly lower in districts having a low annual rainfall (<850 mm), and to be lower in beef cattle than in dairy cattle. A surprising exception to the latter occurred in low rainfall districts, where dairy cattle showed significantly lower reactor rates than local beef animals. 相似文献
1000.