全文获取类型
收费全文 | 226篇 |
免费 | 14篇 |
国内免费 | 108篇 |
专业分类
林业 | 11篇 |
农学 | 77篇 |
基础科学 | 8篇 |
12篇 | |
综合类 | 85篇 |
农作物 | 138篇 |
水产渔业 | 2篇 |
畜牧兽医 | 3篇 |
园艺 | 10篇 |
植物保护 | 2篇 |
出版年
2024年 | 3篇 |
2023年 | 1篇 |
2022年 | 11篇 |
2021年 | 5篇 |
2020年 | 18篇 |
2019年 | 13篇 |
2018年 | 10篇 |
2017年 | 13篇 |
2016年 | 8篇 |
2015年 | 8篇 |
2014年 | 15篇 |
2013年 | 17篇 |
2012年 | 14篇 |
2011年 | 34篇 |
2010年 | 16篇 |
2009年 | 19篇 |
2008年 | 17篇 |
2007年 | 22篇 |
2006年 | 21篇 |
2005年 | 12篇 |
2004年 | 10篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
排序方式: 共有348条查询结果,搜索用时 15 毫秒
101.
Xiaxiang Zhang Jian Cai Bernd Wollenweber Fulai Liu Tingbo Dai Weixing Cao Dong Jiang 《Journal of Cereal Science》2013
Spring wheat plants were subjected to water deficit and/or high temperature episodes at spikelet initiation, anthesis or both stages. The stresses modified the early dough stage and maturity, shortened the kernel desiccation period and caused grain yield loss. Plants subjected to stress at the early growth stages had higher grain yields than the non-early-stressed plants when stress reoccurred at anthesis. Concentrations of high molecular weight glutenin subunits in grain were up-regulated by the single early drought, the early drought combined with late heat and the double drought stress treatments, but was down-regulated by the early heat and double heat stress events. Concentration of glutenin macropolymers was increased by the single early drought episode, the single late drought and heat events, as well as the early drought combined with the late heat stress, but was reduced by the early heat stress and double heat events. 相似文献
102.
103.
K. Sorkheh B. Shiran M. Khodambashi H. Moradi T.M. Gradziel P. Martínez-Gómez 《Scientia Horticulturae》2010
Correlations between 29 quantitative tree and fruit traits were studied in 46 almond genotypes and some inter-specific crosses. Results reflected a significant diversity in the assayed almond germplasm. In addition, the obtained cluster demonstrated varying degrees of relationships, illustrating higher correlation values for the flowering traits and lower correlation values for the nut and kernel traits. To determine the importance of the traits and the levels of similarity existing between the various studied traits, a discriminate analysis was carried out. According to the results obtained from these analyses, the different traits were discriminated on basis of the characteristics of the presence of double kernels, the nut and the kernel size, the flowering date, kernel yield and shelling percentage. Finally, this study evidenced correlations between most of the agronomic traits in almond, although the correlations coefficient (r) value was found to be higher than 0.5 only in some cases. This analysis can help breeders for choosing the most favorable entries to build a core subset of the almond collection for the purpose of breeding. 相似文献
104.
105.
普通小麦F_(2)单粒种子蛋白质含量的遗传 总被引:1,自引:0,他引:1
用近红外漫反射光谱分析对普通小麦两个杂交组合的F_2子粒以及亲本子粒蛋白质含量进行测定,揭示了F_2子粗蛋白质含量的倾低亲遗传以及无超亲分离现象,提出轮回选择是小麦蛋白质育种的最佳选择途径。 相似文献
106.
以生产上主栽的20个普通玉米单交种为测验种,以4个高油品种为被测系,利用不完全随机区组设计分析被测系油分的配合力及油分杂种优势。结果表明,高油115、高油202有较好的一般配合力,与普通玉米单交种杂交当代子粒的油分值较高,是普通玉米高油化较好的授粉者;高油298、高油6可以与沈单15、辽单37、丹2109等油分一般配合力较好的普通玉米单交种作配套组合,来提高普通玉米的油分;油分配合力较差的普通玉米沈单16、农大62、唐玉10等与高油玉米杂交当代子粒的油分值并没有达到含油量5%的标准,它们不宜作为普通玉米高油化的选择对象。以高油玉米为父本,可以使普通玉米单交种的油分平均提高48%,当代子粒油分值=0.68(母本) 0.32(父本)。 相似文献
107.
Wheat is a good source of polyphenols, plant metabolytes with beneficial effects on human health. However, little information is available on phenolic acid composition and concentration in different Triticum species, as well as on possible environmental effects. To shed some light on this issue, thirty-nine wheat accessions cropped for two years and belonging to different Triticum species (Triticum monococcum, Triticum turgidum ssp. dicoccum, turanicum and durum, Triticum aestivum ssp. spelta and aestivum) were assessed for phenolic acids (ferulic, p-coumaric, vanillic, syringic, p-hydroxybenzoic, caffeic acids and syringaldehyde), total polyphenols and antioxidant activity in soluble conjugated and insoluble bound extracts. Ferulic acid was the most abundant compound in both extracts. Insoluble bound phenolic acids represented >90% of total phenolic acids. Einkorn showed the maximum concentration of conjugated phenolic acids (50.5 mg/kg DM), while durum and bread wheats presented the highest content of bound phenolic acids (651.8 and 629.2 mg/kg DM, respectively). Cropping year influenced the concentration of conjugated but not of bound phenolic acids. A survey of phenolic acid distribution in the kernel showed that they are rare in endosperm, but abundant in germ and bran. Total polyphenols and antioxidant activity were highly correlated to phenolic acid content. 相似文献
108.
弱光胁迫对不同基因型玉米雌雄花发育和授粉结实能力的影响 总被引:5,自引:0,他引:5
以不耐阴型玉米豫玉22和耐阴型玉米郑单958为试验材料,设置自然光照和弱光胁迫两个处理,研究弱光胁迫对不同基因型玉米雌雄花发育的影响。研究结果表明,弱光胁迫延缓了雌雄穗的生长发育,表现为抽雄、吐丝和盛花期延迟,花期和雌雄间隔期延长。弱光胁迫下,在吐丝期不耐阴型玉米花粉量比对照显著增加,耐阴型玉米花粉量与对照差异较小;不耐阴型玉米花粉表面网纹在弱光胁迫下变粗且间隙增大,花粉萌发孔及其附近严重畸形,有的明显内陷,花粉内淀粉粒数目显著减少,营养供应能力减弱,耐阴型玉米在弱光胁迫下花粉表面网纹略有加粗或没有变化,萌发孔略微凹陷且程度远低于不耐阴型玉米,花粉中淀粉粒密度略有降低。遮光处理后,不耐阴型玉米的花粉活力、花粉萌发率和萌发速率表现为下降,而耐阴型玉米表现为上升。花丝的生长速率及伸出苞叶数量在弱光胁迫下显著下降,果穗上部花丝受到的影响最大,向下逐渐减弱。弱光胁迫下两个基因型玉米穗长和穗粒数减少,不耐阴型玉米受弱光胁迫影响的程度高于耐阴型玉米。雌雄间隔期延长、营养供应能力减弱导致的花粉畸形、花丝生长速率和可授粉花丝数目的减少以及籽粒IAA含量的下降和ABA含量的增加是弱光条件下玉米穗粒数显著减少的主要原因。 相似文献
109.
110.
新疆引进美国扁桃品种种仁的品质特性 总被引:4,自引:0,他引:4
为了解新疆引进美国扁桃品种的品质特性,以本地品种纸皮为对照(CK),对Nonpareil、Sonora、Mission、Thompson、Ne puls ultra和Butte 6个美国扁桃品种种仁的7种常规成分、9种矿质元素、17种氨基酸和5种脂肪酸含量进行对比研究。结果表明,美国扁桃品种与本地扁桃品种都含有丰富的营养物质,测定的成分互有高低,脂肪、水解后还原糖、Na、P、Ca、亚油酸的含量美国品种间均值高于对照,而蛋白质、还原糖、Vc、K、Cu、Zn、油酸的含量美国品种间均值低于对照,灰分、干物质、氨基酸、Fe、Mg、Mn、棕榈酸等指标的含量两者相当。说明新疆喀什引进的美国扁桃品种保持了扁桃种仁营养丰富的品质特性,适应当地的气候条件。 相似文献