全文获取类型
收费全文 | 224篇 |
免费 | 9篇 |
专业分类
林业 | 111篇 |
农学 | 2篇 |
16篇 | |
综合类 | 19篇 |
农作物 | 8篇 |
水产渔业 | 4篇 |
畜牧兽医 | 62篇 |
园艺 | 3篇 |
植物保护 | 8篇 |
出版年
2018年 | 3篇 |
2016年 | 5篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2010年 | 5篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 21篇 |
2005年 | 8篇 |
2002年 | 3篇 |
2000年 | 3篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1989年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1968年 | 2篇 |
1961年 | 2篇 |
1938年 | 3篇 |
1936年 | 3篇 |
1931年 | 4篇 |
1930年 | 3篇 |
1928年 | 2篇 |
1927年 | 2篇 |
1926年 | 3篇 |
1925年 | 2篇 |
1924年 | 3篇 |
1922年 | 2篇 |
1916年 | 2篇 |
1915年 | 3篇 |
1913年 | 2篇 |
1909年 | 7篇 |
1908年 | 5篇 |
1907年 | 2篇 |
1906年 | 5篇 |
1902年 | 3篇 |
1901年 | 2篇 |
1898年 | 3篇 |
1894年 | 2篇 |
排序方式: 共有233条查询结果,搜索用时 15 毫秒
31.
LIU Yu-hua ZHANG Li-feng 《中国农业科学(英文版)》2006,5(2):98-102
Quantitative indexes such as land equivalent ratio, yield equivalent and value of output equivalent were used to evaluate output efficiencies of different cropping patterns, i.e., sequential cropping, intercrops and crop rotation. Compared to single cropping, land use efficiencies under sequential cropping, intercrops and crop rotation were raised by 62, 38 and 21%, respectively. The unit area yield under sequential cropping, intercrops and crop rotation were raised by 63, 29 and 16%, respectively. The unit area value was also enhanced under sequential cropping and intercrops, 76 and 35% higher than that under single cropping. The paper provides a useful tool for comparing farm output efficiency and build up a theoretical basis for further research on output efficiency of various cropping patterns in the future. 相似文献
32.
The Lapinized Chinese Strain Vaccine Against Classical Swine Fever Virus: A Retrospective Review Spanning Half A Century 总被引:2,自引:0,他引:2
QIU Hua-ji SHEN Rong-xian TONG Guang-zhi 《中国农业科学(英文版)》2006,5(1):1-14
Classical swine fever (CSF), a list A disease of Office International des Epizooties, is caused by classical swine fever virus (CSFV) belonging to the Flaviviridae family. The well-known lapinized Chinese strain of CSFV, also known as C-strain, was developed in China in the mid-1950s. In the past half a century, the vaccine has been proved to be safe and immunogenic in pigs of essentially any age. It is of high efficacy, providing immunized animals with broad-spectrum, sometimes lifelong, protection, which is contributed by both cell-mediated immunity and humoral immunity, against essentially all genotypes or subgenotypes of the virus. The maternal antibodies derived from immunized sows can confer solid protection of their offspring from disease; however, they have been proved to inhibit the successful active immunization of C-strain vaccine. The complete genomes of C-strain and dozens of established or field strains have been sequenced and annotated. Recently, the reverse genetics system of C-strain has been developed, resulting in several C- strain-derived candidate marker vaccines. Many countries manage to control or even eradicate CSF with the aid of mass vaccination with C-strain. in spite of these efforts, the eradication of the disease worldwide remains a big challenge and needs to go a long way, and provably still resorts to genetically modified C-strain vaccine. The authors present an overview of the characteristics of the vaccine, which has stood the test of half a century. 相似文献
33.
Professor C. E. Jonhson 《Soil & Tillage Research》1986,6(4):378-379
34.
35.
36.
37.
38.
39.
40.