全文获取类型
收费全文 | 2473篇 |
免费 | 133篇 |
国内免费 | 192篇 |
专业分类
林业 | 181篇 |
农学 | 116篇 |
基础科学 | 118篇 |
258篇 | |
综合类 | 1133篇 |
农作物 | 172篇 |
水产渔业 | 84篇 |
畜牧兽医 | 437篇 |
园艺 | 169篇 |
植物保护 | 130篇 |
出版年
2024年 | 14篇 |
2023年 | 52篇 |
2022年 | 104篇 |
2021年 | 106篇 |
2020年 | 115篇 |
2019年 | 78篇 |
2018年 | 60篇 |
2017年 | 148篇 |
2016年 | 81篇 |
2015年 | 117篇 |
2014年 | 113篇 |
2013年 | 141篇 |
2012年 | 213篇 |
2011年 | 219篇 |
2010年 | 205篇 |
2009年 | 193篇 |
2008年 | 186篇 |
2007年 | 131篇 |
2006年 | 141篇 |
2005年 | 124篇 |
2004年 | 76篇 |
2003年 | 49篇 |
2002年 | 44篇 |
2001年 | 46篇 |
2000年 | 22篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1988年 | 1篇 |
1986年 | 3篇 |
1981年 | 1篇 |
1962年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有2798条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
Based on a field investigation and laboratory trials, this study compared the invasive ecology of aquatic and terrestrial alligator weed (Alternanthera philoxeroides G.) ecotypes. The aquatic ecotype showed a stronger eco‐adaptation than the terrestrial ecotype. Alligator weed performed well in wetland and riparian habitats, where it was so competitive that only one‐to‐three other plant types grew successfully in its company. In contrast, it exhibited poor growth in upland fields and parks, where the terrestrial ecotype was dominated by 6–11 other alien plant species. The aquatic ecotype exhibited significantly greater growth inhibition of Microcystis aeruginosa. The ecotypes differed in their pattern of allelopathic inhibition of water blooms. The allelopathic effect of the aquatic ecotype persisted for a period exceeding 20 days, whereas the terrestrial ecotype's allelopathic effect subsided in <5 days. The aquatic ecotype had higher levels of antioxidant compounds, including soluble protein and flavones, and the activity of protective enzymes was also higher, which included superoxidase dismutase, peroxidase and catalase. Alligator weed's unique characteristics derive mainly from its strong allelopathic potential and tolerance of eutrophication in aquatic habitats. 相似文献
105.
106.
加强猕猴桃的后期管理 ,是提高果实品质 ,保证正常成熟的重要环节。1 改善光照条件8月中旬高温期过后 ,对二次副梢或三次副梢进行缩剪 ,若春梢摘心留叶数为 8片或 1 0片叶时 ,二次枝应在 3片至 5片叶处短截 ;有三次副梢出现的旺枝 ,将三次枝留 2片至 3片叶重剪或直接疏去。若春梢在 4片叶至 6片叶处缩剪 ,二次枝亦应在 4片至 6片叶处缩剪 ,将三次或四次副梢疏去。树势较旺者 ,对内膛细弱枝或自封顶枝 ,应适当中截着果节以上的枝段。行与行之间留足 80~ 1 0 0cm的间距 ,避免行间枝梢交叉。秋剪的主要对象是二次或三次 (四次 )副梢及其他… 相似文献
107.
108.
109.
WANG Jun DENG Chang-yan XIONG Yuan-zhu ZUO Bo CHENG Huan-chen LI Feng-e LEI Ming-gang ZHENG Rong JIANG Si-wen 《中国农业科学(英文版)》2006,5(5)
Hexokinase Ⅱ has been demonstrated to play the role of a key enzyme member in the glycolysis reaction. It catalyzes the conversion of glucose to glucose-6-phosphate, thus committing glucose to the glycolytic pathway. In this paper, the partial exons and introns 10, 11, 13 and 14 of the porcine HK2 gene were cloned and sequenced by comparative genomics.Comparative sequencing of three pig breeds revealed ten putative single-nucleotide polymorphisms (SNPs), one of which in intron 10 with differing bases (G981A) is within the restriction site for enzyme Msp Ⅰ. Distribution of Msp Ⅰ -RFLP genotype and allele frequencies among different pig breeds were studied. By association analysis between Msp Ⅰ PCR-RFLP polymorphism (AA, AB, BB genotypes of HK2 gene intron 10) and some meat quality and carcass traits in F2 group,which was constructed by our laboratory, a significant difference of pig average backfat at rump was found between AB and BB genotypes (P < 0 05) in F2 group. In addition, the pattern of expression of HK2 in a variety of tissues in pig was also determined using semi-quantitative RT-PCR. The expression of HK2 mRNA was detected only in pig skeletal muscle. 相似文献
110.
普那菊苣饲喂三元杂交猪的效果 总被引:1,自引:0,他引:1
利用普那菊苣青绿叶片配合精料育肥三元杂交肉猪,经过105 d的育肥,在5个不同搭配组合中,当青料干物质占日粮干物质的25.96%时,头日均增重最快,为692.12 g;瘦肉率较高,为63.78%,与对照差异达极显著(P<0.01);屠宰率为74.06%,饲料转化率为3.02 kg,比对照低,但成本减少61.93元,效益增加60.19元;经济效益最高,为173.36元,与其他几个组合差异极显著(P<0.01),是一个比较理想的搭配组合,可直接用于生产推广. 相似文献