全文获取类型
收费全文 | 2189篇 |
免费 | 202篇 |
国内免费 | 324篇 |
专业分类
林业 | 47篇 |
农学 | 472篇 |
基础科学 | 2篇 |
145篇 | |
综合类 | 812篇 |
农作物 | 251篇 |
水产渔业 | 152篇 |
畜牧兽医 | 499篇 |
园艺 | 84篇 |
植物保护 | 251篇 |
出版年
2024年 | 21篇 |
2023年 | 71篇 |
2022年 | 129篇 |
2021年 | 147篇 |
2020年 | 172篇 |
2019年 | 145篇 |
2018年 | 91篇 |
2017年 | 129篇 |
2016年 | 124篇 |
2015年 | 104篇 |
2014年 | 132篇 |
2013年 | 115篇 |
2012年 | 135篇 |
2011年 | 147篇 |
2010年 | 106篇 |
2009年 | 117篇 |
2008年 | 90篇 |
2007年 | 108篇 |
2006年 | 89篇 |
2005年 | 72篇 |
2004年 | 63篇 |
2003年 | 47篇 |
2002年 | 37篇 |
2001年 | 38篇 |
2000年 | 27篇 |
1999年 | 28篇 |
1998年 | 16篇 |
1997年 | 24篇 |
1996年 | 24篇 |
1995年 | 19篇 |
1994年 | 14篇 |
1993年 | 15篇 |
1992年 | 22篇 |
1991年 | 11篇 |
1990年 | 12篇 |
1989年 | 14篇 |
1988年 | 3篇 |
1987年 | 9篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1956年 | 3篇 |
1955年 | 4篇 |
排序方式: 共有2715条查询结果,搜索用时 15 毫秒
41.
旨在鉴别影响苏山猪初生体尺和乳头数性状的遗传位点,开发可用于辅助育种的分子标记,为苏山猪生长和繁殖性能的持续选育提供理论基础。本试验对269头苏山猪初生仔猪(出生后24 h内)的体尺和乳头数表型进行测定,并采集耳组织样品。基于全基因组重测序及基因型填充策略,利用全基因组关联分析(genome-wide association study, GWAS)和群体分化指数(fixation index,Fst)的方法挖掘与目的性状强关联位点,并对位置功能候选基因开展GO和KEGG分析,确定最有可能的主效基因。本研究共鉴别到4个候选位点,分布在13、14和X染色体上,其中与初生体尺性状显著关联的位点有2个,与乳头数性状显著关联的位点有2个。本研究筛选出1个与体长性状相关的候选基因ACTA2;1个与胸围性状相关的候选基因COL4A6;3个与乳头数性状相关的候选基因ACTA2、CRTAP和SEPTIN6,为苏山猪初生体尺性状和乳头数性状的遗传改良提供了重要的分子标记。 相似文献
42.
为认识桃芽休眠诱导过程中生理与相关基因表达的变化,分别用HPLC检测‘中农红久保’、‘中农3号’、03-30-035 3个桃品种(系)休眠诱导时期叶片和叶芽IAA和ABA含量,用RT-q PCR检测叶片和叶芽生长素极性运输载体基因Pp PIN1、Pp PIN3、Pp PIN5和Pp PIN8共4个基因的相对表达量。结果表明,在桃芽休眠诱导过程中,叶片IAA含量未见显著变化,ABA含量自10月6日开始升高,至10月16日含量达到高峰;叶芽中10月上中旬IAA含量骤增,而ABA含量逐渐降低。本研究中桃基因组的4个Pp PINs基因家族成员中,叶片中活跃表达为Pp PIN5,其次为Pp PIN3,在10月上中旬Pp PIN5出现强烈表达;而在10月26日,叶芽中活跃表达的Pp PIN1和Pp PIN3表达量骤降。桃休眠诱导过程中叶片和叶芽内内源激素和Pp PINs基因表达量变化明显不同。 相似文献
43.
44.
45.
Nitrogen (N) is critical for micronutrient biofortification in wheat grain and is essential for a series of nitrogenous compounds biosynthesis. This study aims to assess the role of improved N supply in iron (Fe) and zinc (Zn) enrichment and expression of genes related to Zn and Fe chelation and transport in winter wheat. Potting and hydroponic culture experiments were conducted to study the effect of increasing N application on Zn and Fe uptake and translocation from roots to leaves and the temporal and spatial gene expression profiles of the NICOTIANAMINE SYNTHASE (NAS) genes in wheat. Plants were grown with low, medium and high N supply levels. The results showed that higher N application increased Fe and Zn content in leaves, and decreased Fe and Zn content in root compared with the lower N supply. High N application also increased the distribution of Fe and Zn from roots to leaves. Expression analysis showed that increased N application resulted in up-regulation of two wheat NAS genes, TaNAS1 and TaNAS2. Highly positive response between NAS genes and increasing N application indicated that abundance nicotianamine (NA) resulted from highly expressed NAS genes might involve in the chelation of Fe and Zn in the phloem and favor Fe and Zn uptake and accumulation in wheat leaves. 相似文献
46.
47.
48.
49.
Inducible responses in plants against pathogen attack play a major role in resistance to disease. The defense responses are
mostly associated with the expression of various kinds of inducible genes. We employed differential hybridization to isolate
elicitor-inducible genes (EIGs) of tobacco (Nicotiana tabacum cv. Samsun NN) using the tobacco-fungal elicitor system. A cDNA library was constructed from tobacco leaves treated for 12
hr with hyphal wall components (HWC) prepared from Phytophthora infestans, and six EIGs were identified. Expression of all EIGs was induced after inoculation with the soybean pathogen Pseudomonas syringae pv. glycinea (nonpathogenic on tobacco) or treatment with salicylic acid, and a variety of expression patterns of EIG mRNAs was observed.
Sequence analysis of EIG cDNAs revealed similarities to genes for SAR8.2 (EIG-B39 and EIG-D14), glycine-rich protein (EIG-G7), extensin (EIG-I30), acyltransferase (EIG-I24) and unknown protein (EIG-J7). Possible roles of EIG products in disease resistance are discussed.
Received 30 August 2000/ Accepted in revised form 30 November 2000 相似文献
50.
P. Castagnone-Sereno M. Bongiovanni A. Palloix A. Dalmasso 《European journal of plant pathology / European Foundation for Plant Pathology》1996,102(6):585-590
Experiments were designed to analyze the relationships between the root-knot nematodeMeloidogyne incognita and resistant tomato and pepper genotypes. From a natural avirulent isolate, near-isogenic nematode lineages were selected with virulence either against the tomatoMi resistance gene or the pepperMe3 resistance gene. Despite the drastic selection pressure used, nematodes appeared unable to overcome the pepperMe1 gene, therefore suggesting some differences in the resistance conferred byMe1 andMe3 in this species. Nematodes virulent onMi-resistant tomatoes were not able to reproduce onMe1-resistant nor onMe3-resistant peppers, and nematodes virulent onMe3-resistant peppers were not able to reproduce onMi-resistant tomatoes nor onMe1-resistant peppers. These results clearly demonstrate the specificity ofM. incognita virulence against resistance genes from both tomato and pepper, and indirectly suggest that gene-for-gene relationships could occur between these two solanaceous crops and the nematode. 相似文献