全文获取类型
收费全文 | 41217篇 |
免费 | 1786篇 |
国内免费 | 7017篇 |
专业分类
林业 | 833篇 |
农学 | 5917篇 |
基础科学 | 2193篇 |
6900篇 | |
综合类 | 21303篇 |
农作物 | 7924篇 |
水产渔业 | 284篇 |
畜牧兽医 | 1039篇 |
园艺 | 187篇 |
植物保护 | 3440篇 |
出版年
2024年 | 286篇 |
2023年 | 745篇 |
2022年 | 1303篇 |
2021年 | 1504篇 |
2020年 | 1438篇 |
2019年 | 1595篇 |
2018年 | 1195篇 |
2017年 | 1800篇 |
2016年 | 2288篇 |
2015年 | 1737篇 |
2014年 | 2328篇 |
2013年 | 2444篇 |
2012年 | 3167篇 |
2011年 | 2839篇 |
2010年 | 2387篇 |
2009年 | 2496篇 |
2008年 | 2098篇 |
2007年 | 2442篇 |
2006年 | 2103篇 |
2005年 | 1916篇 |
2004年 | 1464篇 |
2003年 | 1400篇 |
2002年 | 1054篇 |
2001年 | 1043篇 |
2000年 | 947篇 |
1999年 | 754篇 |
1998年 | 680篇 |
1997年 | 582篇 |
1996年 | 604篇 |
1995年 | 540篇 |
1994年 | 434篇 |
1993年 | 451篇 |
1992年 | 405篇 |
1991年 | 328篇 |
1990年 | 330篇 |
1989年 | 250篇 |
1988年 | 168篇 |
1987年 | 161篇 |
1986年 | 118篇 |
1985年 | 26篇 |
1984年 | 30篇 |
1982年 | 18篇 |
1981年 | 25篇 |
1980年 | 8篇 |
1979年 | 12篇 |
1978年 | 12篇 |
1977年 | 14篇 |
1976年 | 18篇 |
1962年 | 17篇 |
1955年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
中浙优8号在沙县作烟后稻种植表现及高产栽培技术 总被引:1,自引:0,他引:1
中浙优8号是中国水稻研究所和浙江勿忘农种业股份有限公司采用优质不育系中浙A与恢复系T-8配组而成的优质高产迟熟三系杂交稻新品种,经过3 a在沙县作烟后稻示范种植,表现群体整齐、分蘖力强、结实率高、米质较优、丰产稳产性好等特点。介绍其在沙县示范表现及高产栽培技术。 相似文献
162.
[目的]研究399对"一种两收"再生稻的影响。[方法]以适宜丘陵红黄壤种植的丰两优香1号、准两优527、宜优673再生稻品种为材料,分别设置喷施399和不喷施399(CK)2种处理,研究各处理对再生稻根系和产量的影响。[结果]结果表明:施用399使水稻在生育期上延缓成熟,且施后再生稻的总根系数量、白根数量、根鲜重、根干重、根体积大幅度增加,同时在两季总产量上准两优527、丰两优香1号和宜优673品种分别比对照增产6.39%、4.86%、5.94%。[结论]施用399有利于准两优527、丰两优香1号和宜优673再生稻品种再生根的发生。 相似文献
163.
164.
真核翻译延伸因子(eukaryotic translation elongation factor,eEFs)是一种重要的多功能调控蛋白,eEF1β是eEF1的组成部分,在蛋白质生物合成过程中发挥着重要的作用。本文通过RT-PCR扩增克隆小麦(Triticum aestivum L.)的eEF1β基因,并命名为TaeEF1β。氨基酸同源性分析发现,TaeEF1β具有高度保守性,且其保守结构域位于137~226 aa处。qRT-PCR结果表明,中国小麦花叶病毒(Chinese wheat mosaic virus,CWMV)侵染小麦植株后,可以诱导TaeEF1β基因转录水平的上调表达。另外,本文也进一步分析了TaeEF1β基因在小麦根、茎、叶的表达水平和CWMV侵染不同时间点的表达情况。 相似文献
165.
166.
167.
Evaluating the role of seed priming in improving drought tolerance of pigmented and non‐pigmented rice 下载免费PDF全文
This study was conducted to evaluate the influence of seed priming on drought tolerance of pigmented and non‐pigmented rice. Seeds of pigmented (cv. Heug Jinju Byeo) and non‐pigmented (cv. Anjoong) rice were soaked in water (hydropriming) or solution of CaCl2 (osmopriming). Seeds were sown in soil‐filled pots retained at 70 (well‐watered) and 35% (drought) water‐holding capacity. Drought stress caused erratic and poor stand establishment and decreased the growth of both rice types. More decrease in plant height and leaf area under drought stress was noted in pigmented rice, whereas decrease in root length and seedling dry weight, under drought, was more obvious in non‐pigmented rice. Pigmented rice maintained more tissue water and photosynthesis and had more polyphenols, flavonoids and antioxidant activity than non‐pigmented rice. Seed priming was effective in improving stand establishment, growth, polyphenols, flavonoids and antioxidant activity; however, extent of improvement was more in pigmented rice under drought. In conclusion, drought caused erratic germination and suppressed plant growth in both rice types. However, pigmented rice had better drought tolerance owing to uniform emergence, and better physiological and morphological plasticity. Seed priming was quite helpful in improving the performance of both rice types under drought and well‐watered conditions. 相似文献
168.
New strategies to enhance growth and productivity of food crops in saline soils represent important research priorities. This study has investigated the role of certain priming techniques to induce salt tolerance of bread wheat. Wheat grains were soaked in 0.2 mm sodium nitroprusside as nitric oxide donor (redox priming), diluted sea water (halopriming) and the combination of both (redox halopriming). Grains were also soaked in distilled water (hydropriming); in addition, untreated grains were taken as control. Our results indicated that priming treatments significantly improved all growth traits and increased leaf pigments concentration as compared to the control. Priming treatments markedly enhanced membrane stability index, proline, total soluble sugars and K+ concentration with simultaneous decrease in the concentration of Na+ and malondialdehyde (MDA). Furthermore, yield and yield‐related traits such as plant height, spike length, total number of tillers, 1000‐grain weight, straw and grain yield considerably affected by priming treatments. Moreover, the grain yield of both genotypes was positively affected by redox halopriming treatment. However, the extent of enhancement was more prominent in Gemmiza‐9 (salt sensitive) than that in Sakha‐93 (salt‐tolerant). Overall, this study clearly indicated that redox halopriming treatment is a promising and handy technique to induce salinity tolerance of wheat genotypes. 相似文献
169.
野生稻是一个重要的基因资源库,包含了水稻各种病害的抗性基因。本文综述了野生稻丰富的抗性资源及其基因的挖掘,以及在水稻育种上的利用研究进展,并对目前存在的突出问题,提出了野生稻种质资源抗病育种的发展建议。 相似文献
170.