全文获取类型
收费全文 | 1913篇 |
免费 | 135篇 |
国内免费 | 168篇 |
专业分类
林业 | 125篇 |
农学 | 185篇 |
基础科学 | 62篇 |
141篇 | |
综合类 | 827篇 |
农作物 | 184篇 |
水产渔业 | 60篇 |
畜牧兽医 | 183篇 |
园艺 | 94篇 |
植物保护 | 355篇 |
出版年
2024年 | 10篇 |
2023年 | 28篇 |
2022年 | 51篇 |
2021年 | 65篇 |
2020年 | 65篇 |
2019年 | 67篇 |
2018年 | 48篇 |
2017年 | 66篇 |
2016年 | 80篇 |
2015年 | 76篇 |
2014年 | 101篇 |
2013年 | 122篇 |
2012年 | 147篇 |
2011年 | 137篇 |
2010年 | 111篇 |
2009年 | 92篇 |
2008年 | 92篇 |
2007年 | 105篇 |
2006年 | 104篇 |
2005年 | 92篇 |
2004年 | 60篇 |
2003年 | 59篇 |
2002年 | 73篇 |
2001年 | 48篇 |
2000年 | 40篇 |
1999年 | 47篇 |
1998年 | 20篇 |
1997年 | 30篇 |
1996年 | 19篇 |
1995年 | 23篇 |
1994年 | 14篇 |
1993年 | 25篇 |
1992年 | 11篇 |
1991年 | 15篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 8篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有2216条查询结果,搜索用时 46 毫秒
31.
XIAO Gang ZHANG Zhen-qian LIU Rui-yang YIN Chang-fa WU Xian-meng TAN Tai-long GUAN Chun-yun 《中国农业科学(英文版)》2013,(6):962-970
Based on the sequence of a novel expressed sequence tag (EST), the full-length cDNA of 1 017 nucleotides was cloned from Brassica napus cv. Xiangyou 15 through rapid amplification of cDNA ends (RACE). The gene was designated as Bnhol34 (HQ585980), encoding a protein of 338 amino acids. BLAST analysis showed no high degree of sequence identity to any known gene. The calculated molecular weight of the Bnhol34 protein was 36.23 kDa, and the theoretical isoelectric point was 8.74. The Bnhol34 was also cloned from a high oleic acid mutant 854-1 through homologous cloning. There was no difference between the two Bnhol34 genes. Bnhol34 was localized in a tissue-specific manner in B. napus, and its expression level was about eight-fold greater in Xiangyou 15 seeds than in 854-1. The promoter region sequences of Bnhol34 were then isolated from Xiangyou 15 and 854-1, and a 93-bp deletion was found to occur in the Bnhol34 promoter region of 854-1. Three abscisic acid-responsive cis-elements (ABRE) were identified in the promoter region of Xiangyou 15. Real-time PCR analyses revealed that exogenous abscisic acid increased Bnhol34 expression by about four-fold in Xiangyou 15 seeds, yet did not change Bnhol34 expression in 854-1. It appeared that Bnhol34 might be abscisic acid insensitive in 854-1. 相似文献
32.
33.
ACC合成酶(ACS)和ACC氧化酶(ACO)是催化乙烯生物合成的两个关键酶,这两个酶的基因在调控果品和花卉完熟及衰老方面具有重要意义,本文综述了ACS和ACO基因最新研究进展。 相似文献
34.
35.
Inoculation of nonhost pepper ( Capsicum annuum ) plants with the tomato wilt pathogen, Fusarium oxysporum f.sp. lycopersici (FOL), caused no symptoms and the fungus was not recovered from any part of the plant. FOL, however, partially protected pepper plants from subsequent infection with Phytophthora capsici , Verticillium dahliae or Botrytis cinerea by significantly reducing the percentage of diseased plants and the appearance and intensity of symptoms. FOL did not inhibit the mycelial growth of these pathogens in vitro . The protection induced by FOL against Botrytis was inhibited by 1-methylcyclopropene (MCP), an inhibitor of ethylene perception, suggesting the involvement of this hormone in the signalling of FOL-induced resistance. The activities of β-1,3-glucanase and peroxidase 48 h after FOL induction were similar to those in control plants. Chitinase activity, however, was higher in the stems of plants inoculated with FOL. A study of the levels of phenolic compounds revealed that cell-wall-bound phenolics were more abundant in plants treated with FOL, especially in stems, while soluble phenolic contents did not differ. 相似文献
36.
以水溶性聚合物聚乙烯醇(PVA)和水不溶性聚合物乙酸乙烯-乙烯共聚物(VAE)乳液为原料,采用溶液共混法制备了PVA-VAE共混膜,为农药成膜剂的制备开辟了新途径。红外光谱、透射电镜、激光粒度仪测试结果显示,PVA溶液中的胶束被打开,体系的比表面积急剧增大,两相间的界面消失,说明共混体系分子间具有良好的相容性;透水性与耐水性测定结果表明,PVA-VAE的质量比为80∶ 20、70∶ 30、60∶ 40时其共混膜的性能适用于农药种衣剂的成膜剂;种子发芽试验显示,与单独使用PVA膜相比,引入适当比例VAE后的共混膜用于种子包衣,其耐水性显著提高,渗水率适宜,对种子发芽无明显影响。 相似文献
37.
38.
39.
条锈菌侵染早期小麦叶片RNA和rRNA的合成 总被引:1,自引:0,他引:1
采用示踪方法研究了条锈菌侵染早期小麦叶片的RNA和rRNA合成。结果表21h期间,表现不亲和性反应的叶片总RNA合成有所增加,而亲和性反应寄主叶片则低rRNA合成未受侵染影响。在接种后39~45h期间,只有呈亲和性反应的寄主叶片RNA和大幅度增加。对rRNA各组分合成的测定表明条锈菌侵染所影响的只是大分子量rRNA,胞质和叶绿体rRNA的合成也存在差别。文中讨论了上述变化的病理学意义。 相似文献
40.
William S. Bowers Gopalan C. Unnithan Jun-Ichi Fukushima Jun Toda Takeyoshi Sugiyama 《Pest management science》1995,43(1):1-11
Twenty-one synthetic compounds, containing one or more furan rings, were demonstrated to possess anti-juvenile hormone (AJH) activity as evidenced by their induction of premature metamorphosis in the milkweed bug, Oncopeltus fasciatus (Dallas) by contact, topical application or fumigation. The ED50 of the four most active analogs required to induce precocious metamorphosis from 3rd-instar nymphs by residue contact in a Petri dish compared favorably with that of precocene II (6,7-dimethoxy-2,2-dimethyl 2H-chromene) a naturally occurring phytochemical AJH. Precocious metamorphosis was fully reversible by co-treatment with juvenile hormone (JH III) or JH analogs, demonstrating that the observed AJH activity resulted from an induced deficiency of juvenile hormone. 相似文献