全文获取类型
收费全文 | 84135篇 |
免费 | 4645篇 |
国内免费 | 317篇 |
专业分类
林业 | 4005篇 |
农学 | 2822篇 |
基础科学 | 520篇 |
10710篇 | |
综合类 | 15023篇 |
农作物 | 3284篇 |
水产渔业 | 3882篇 |
畜牧兽医 | 42406篇 |
园艺 | 970篇 |
植物保护 | 5475篇 |
出版年
2019年 | 857篇 |
2018年 | 1408篇 |
2017年 | 1499篇 |
2016年 | 1343篇 |
2015年 | 1169篇 |
2014年 | 1444篇 |
2013年 | 3371篇 |
2012年 | 2584篇 |
2011年 | 2971篇 |
2010年 | 1994篇 |
2009年 | 2097篇 |
2008年 | 2906篇 |
2007年 | 2780篇 |
2006年 | 2604篇 |
2005年 | 2357篇 |
2004年 | 2257篇 |
2003年 | 2234篇 |
2002年 | 2051篇 |
2001年 | 2584篇 |
2000年 | 2530篇 |
1999年 | 2012篇 |
1998年 | 800篇 |
1997年 | 844篇 |
1996年 | 778篇 |
1995年 | 860篇 |
1994年 | 776篇 |
1993年 | 735篇 |
1992年 | 1490篇 |
1991年 | 1620篇 |
1990年 | 1503篇 |
1989年 | 1542篇 |
1988年 | 1439篇 |
1987年 | 1434篇 |
1986年 | 1462篇 |
1985年 | 1409篇 |
1984年 | 1123篇 |
1983年 | 1012篇 |
1979年 | 1145篇 |
1978年 | 920篇 |
1977年 | 789篇 |
1976年 | 785篇 |
1975年 | 857篇 |
1974年 | 1099篇 |
1973年 | 1032篇 |
1972年 | 1065篇 |
1971年 | 961篇 |
1970年 | 931篇 |
1969年 | 942篇 |
1968年 | 773篇 |
1967年 | 828篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
Abstract. A humoral antibody response was demonstrated by ELISA in rainbow trout immunized intraperitoneally with extracts from the branchiuran ectoparasite Argulus foliaceus. A similar immunization protocol produced a higher titre response in a rabbit. Both trout and rabbit identified several antigenic components on immunoblots. ELISA and immunoblotting indicated that rainbow trout and rabbit anti-A. foliaceus sera identified components from the parasitic copepods Lepeophtheirus salmonis and Caligus elongatus. 相似文献
2.
3.
Mid-storage hydration-dehydration treatments with medium-vigour lettuce seed very effectively reduced physiological deterioration in storage and ultimately showed better field emergence and final yield. Soaking-drying treatment of high-vigour lettuce seed was not effective. Pre-sowing treatment of medium-vigour lettuce seed, though less effective than mid-storage treatment, gave better field performance, but high-vigour seed did not benefit from the treatment. For carrot, both mid-storage and pre-sowing seed treatments proved beneficial, with the former showing better performance than the latter. Unlike lettuce, well-preserved carrot seed responded positively to the pre-sowing treatment. 相似文献
4.
5.
6.
Osborn HF 《Science (New York, N.Y.)》1921,54(1403):482-484
7.
8.
9.
Disseminated Aspergillus terreus infection was diagnosed in ten previously healthy adult dogs--nine German shepherds and one dalmatian. The disease was characterized by the presence of multiple granulomas and infarcts in a wide range of organs. The kidney, spleen, and skeletal system were most commonly and severely affected. Fungal hyphae were demonstrated in large numbers within granulomas and thrombi, and A. terreus was readily isolated by culture. This disseminated mycosis appears unique; in this series of cases there was no apparent predisposing factor, portal of entry, or primary focus for dissemination of the infection. 相似文献
10.
J W McBride R E Corstvet D B Paulsen J R McClure F M Enright 《American journal of veterinary research》1992,53(10):1889-1894
Systemic and pulmonary antibody responses of calves to Pasteurella haemolytica were evaluated by measuring immunoglobulin production in blood for 9 days and in pulmonary lavage fluid for 7 days after intrapulmonary inoculation. Clinical signs, pulmonary lesions, pulmonary and systemic inflammatory response, and amount of antigen in lavage fluid were used to evaluate the response of calves to challenge with P haemolytica. The pulmonary response consisted of production of IgG, IgE, and IgM antibodies to P haemolytica antigens and a 17- to 68-fold increase of cells in lavage fluid 8 hours after inoculation, with a gradual decrease toward normal. Antibodies of the IgM isotype to P haemolytica were demonstrated as early as 8 hours through 7 days after inoculation in 3 of 3 calves. Of the anti-P haemolytica isotypes, IgM was found in the highest concentration. In all of the inoculated calves, IgE was found 1 to 2 days after inoculation, and IgG was found in 2 of 3 inoculated calves from day 1 through 7 after inoculation. Detection of IgG correlated with smaller pulmonary lesions. Immunoglobulin A was not detected in lavage fluid. Serum was evaluated for IgG and IgM antibody response to P haemolytica. Specific IgM was detectable 5 days after inoculation, and IgG was detectable 7 days after inoculation. Pasteurella haemolytica antigens were not detected in serum or plasma. A transient increase in neutrophil count was found 8 hours after inoculation, with return to baseline values by 24 hours after inoculation.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献