全文获取类型
收费全文 | 10326篇 |
免费 | 401篇 |
国内免费 | 883篇 |
专业分类
林业 | 927篇 |
农学 | 848篇 |
基础科学 | 1230篇 |
935篇 | |
综合类 | 4100篇 |
农作物 | 454篇 |
水产渔业 | 467篇 |
畜牧兽医 | 1954篇 |
园艺 | 323篇 |
植物保护 | 372篇 |
出版年
2024年 | 72篇 |
2023年 | 199篇 |
2022年 | 328篇 |
2021年 | 337篇 |
2020年 | 341篇 |
2019年 | 437篇 |
2018年 | 243篇 |
2017年 | 394篇 |
2016年 | 554篇 |
2015年 | 414篇 |
2014年 | 647篇 |
2013年 | 562篇 |
2012年 | 950篇 |
2011年 | 802篇 |
2010年 | 612篇 |
2009年 | 570篇 |
2008年 | 490篇 |
2007年 | 519篇 |
2006年 | 490篇 |
2005年 | 323篇 |
2004年 | 309篇 |
2003年 | 223篇 |
2002年 | 190篇 |
2001年 | 191篇 |
2000年 | 158篇 |
1999年 | 150篇 |
1998年 | 139篇 |
1997年 | 120篇 |
1996年 | 105篇 |
1995年 | 116篇 |
1994年 | 111篇 |
1993年 | 74篇 |
1992年 | 93篇 |
1991年 | 74篇 |
1990年 | 62篇 |
1989年 | 57篇 |
1988年 | 59篇 |
1987年 | 27篇 |
1986年 | 14篇 |
1985年 | 7篇 |
1984年 | 12篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1973年 | 2篇 |
1956年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
952.
953.
Dal-Sang Jeong Enrique Blanco Gonzalez Kagayaki Morishima Katsutoshi Arai Tetsuya Umino 《Fisheries Science》2007,73(4):823-830
The genetic contribution of 51 broodstock, comprising 29 females and 22 males, reared at Hiroshima City Marine Products Promotion
Center for the production of stocked black sea bream was monitored during two consecutive years using seven microsatellite
DNA loci. The high discrimination ability of these markers was reflected in the polymorphic identification content (PIC=0.831), the exclusion probability (Q≈1), and the low probability of identity index (I=3.635−10). The total number of breeders contributing to the mating process was estimated at 32 (62.7%) in 2000 and 30 (58.8%) in 2001.
On pedigree reconstruction, 69.3% of the offspring were successfully assigned to a single broodstock pair. Loss of alleles
accounted for 16.9% during seed production; nevertheless, 90.9% of males and 69.0% of females participated in the mating process.
Based on microsatellite genetic tagging, 58.9% of the fish sampled during the two months after release were identified as
hatchery stock, presenting no significant differences from wild conspecifics in either fork length or body weight. 相似文献
954.
Franklin Prez Filip A.M. Volckaert Jorge Caldern 《Aquaculture (Amsterdam, Netherlands)》2005,250(3-4):586-591
White Spot Syndrome Virus (WSSV) has decimated the shrimp aquaculture around the world. Breeding efforts to generate resistant stocks are necessary but there is a lack of basic information on challenge test strategies focused on genetic selection. Infection routes and developmental stages were evaluated on Penaeus vannamei as a first step in a strategy to select white spot virus (WSSV)-resistant stocks. Mortalities could not be induced before the PL30 stage. The impact of infection by immersion and blended tissue was intermediate on mortalities when compared to the minced tissue treatment on PL30. Blended and minced tissue treatments produced the highest mortalities on PL40 while immersion was intermediate. A general tendency towards higher susceptibility associated with older stages was detected. Additionally, juveniles of 1 g average weight from three local breeding programs were challenged. There were no differences in survival between the programs, although two of them derived their progenies from survivors of strong WSSV events. The implications of these results to the WSSV epidemiological characteristics and breeding programs are discussed. 相似文献
955.
956.
957.
958.
959.
960.
就可可种质资源在起源、分布、传播、分类、鉴定及种质创新与利用等方面取得的研究进展进行综述。可可属植物有22种,仅可可(Theobroma cacao)和大花可可(Theobroma grandiflorum)用于栽培。可可种质资源多样性丰富,其分类研究经历了传统形态学划分的Criollo、Forastero和Trinitario遗传类群到现代分子标记划分的Maran~on、Curaray、Criollo、Iquitos、Nanay、Contamana、Amelonado、Purús、Nacional和Guiana遗传类群。目前,可可的生产性品种选育仍以实生选种和芽变选种为主。分子标记的开发、遗传连锁图谱的构建和全基因组测序的完成,为实现可可分子标记辅助育种提供了技术保障。 相似文献