全文获取类型
| 收费全文 | 2275篇 |
| 免费 | 125篇 |
专业分类
| 林业 | 59篇 |
| 农学 | 52篇 |
| 基础科学 | 5篇 |
| 251篇 | |
| 综合类 | 500篇 |
| 农作物 | 54篇 |
| 水产渔业 | 98篇 |
| 畜牧兽医 | 1271篇 |
| 园艺 | 24篇 |
| 植物保护 | 86篇 |
出版年
| 2021年 | 23篇 |
| 2020年 | 29篇 |
| 2019年 | 34篇 |
| 2018年 | 30篇 |
| 2017年 | 23篇 |
| 2016年 | 28篇 |
| 2015年 | 34篇 |
| 2014年 | 35篇 |
| 2013年 | 86篇 |
| 2012年 | 57篇 |
| 2011年 | 100篇 |
| 2010年 | 48篇 |
| 2009年 | 49篇 |
| 2008年 | 82篇 |
| 2007年 | 61篇 |
| 2006年 | 83篇 |
| 2005年 | 67篇 |
| 2004年 | 78篇 |
| 2003年 | 65篇 |
| 2002年 | 52篇 |
| 2001年 | 49篇 |
| 2000年 | 64篇 |
| 1999年 | 49篇 |
| 1998年 | 25篇 |
| 1997年 | 32篇 |
| 1996年 | 22篇 |
| 1995年 | 19篇 |
| 1994年 | 40篇 |
| 1993年 | 53篇 |
| 1992年 | 49篇 |
| 1991年 | 57篇 |
| 1990年 | 57篇 |
| 1989年 | 57篇 |
| 1988年 | 50篇 |
| 1987年 | 39篇 |
| 1986年 | 54篇 |
| 1985年 | 40篇 |
| 1984年 | 29篇 |
| 1983年 | 28篇 |
| 1982年 | 21篇 |
| 1981年 | 30篇 |
| 1979年 | 38篇 |
| 1978年 | 23篇 |
| 1975年 | 25篇 |
| 1974年 | 19篇 |
| 1973年 | 26篇 |
| 1972年 | 29篇 |
| 1971年 | 37篇 |
| 1970年 | 26篇 |
| 1969年 | 30篇 |
排序方式： 共有2400条查询结果，搜索用时 15 毫秒
51.
Harvey RB Young CR Ziprin RL Hume ME Genovese KJ Anderson RC Droleskey RE Stanker LH Nisbet DJ 《Journal of the American Veterinary Medical Association》1999,215(11):1601-1604
OBJECTIVE: To enumerate the prevalence of Campylobacter isolates in the intestinal tract of market-weight swine raised in an integrated swine operation in Texas. SAMPLE POPULATION: Samples of cecal contents were collected from 595 pigs (mean body weight, 110 kg [242 lb]) at time of slaughter. Pigs were off-spring of Yorkshire-Landrace sows and Duroc or Hampshire boars. Pigs originated from 4 farrow-to-finish farms. PROCEDURE: During a 9-month period, visits were made to a slaughter plant to remove cecal contents from market-weight hogs. Samples were obtained from 50 pigs/visit from designated farms so that samples were obtained 3 times from pigs of each of 4 farms. Isolation of Campylobacter spp was accomplished by use of enrichment broth and restrictive media, using microaerophilic conditions. RESULTS: Campylobacter spp were isolated from 70 to 100% of the pigs, depending on the farm and the date the samples were collected. Campylobacter coli was isolated from 20 to 100% (mean, 60%) of samples, and C jejuni was isolated from 0 to 76% (mean, 31%) of samples. Campylobacter lari was isolated from 2 pigs. Concentrations of C coli or C jejuni ranged from 10(3) to 10(7) colony-forming units/g of cecal content. CONCLUSIONS AND CLINICAL RELEVANCE: Campylobacter coli generally is accepted as a common inhabitant of the intestinal tract of swine. However, analysis of results of this study suggests that a relatively high prevalence of C jejuni may be found in pigs raised on specific farms. 相似文献
52.
Borreliosis in equids in northeastern United States 总被引：3，自引：0，他引：3
L A Magnarelli J F Anderson E Shaw J E Post F C Palka 《American journal of veterinary research》1988,49(3):359-362
During 1982 and 1985, blood samples from 705 equids were examined for antibodies to Borrelia burgdorferi. By indirect immunofluorescence staining, IgM and total immunoglobulin (IgM and IgG) antibodies were detected in 37 (5.3%) and 90 (12.8%) serum specimens, respectively. The geometric mean titer for IgM antibody (140.4) was highest during July, whereas total immunoglobulin ranged from 94.1 in October to 338 in May. Eighty-six equids with total immunoglobulin to B burgdorferi lived in areas of Connecticut where the primary tick vector, Ixodes dammini, was present. Of the 86 equids, 9 from Lyme, Connecticut and Westchester County, New York had antibodies to B burgdorferi and developed limb or joint disorders that resulted in single or recurrent episodes of lameness. 相似文献
53.
54.
55.
56.
57.
58.
59.
60.
