全文获取类型
收费全文 | 1218篇 |
免费 | 110篇 |
国内免费 | 52篇 |
专业分类
林业 | 35篇 |
农学 | 129篇 |
28篇 | |
综合类 | 482篇 |
农作物 | 163篇 |
畜牧兽医 | 5篇 |
园艺 | 66篇 |
植物保护 | 472篇 |
出版年
2024年 | 1篇 |
2023年 | 16篇 |
2022年 | 31篇 |
2021年 | 19篇 |
2020年 | 28篇 |
2019年 | 28篇 |
2018年 | 40篇 |
2017年 | 31篇 |
2016年 | 61篇 |
2015年 | 51篇 |
2014年 | 37篇 |
2013年 | 50篇 |
2012年 | 78篇 |
2011年 | 88篇 |
2010年 | 61篇 |
2009年 | 82篇 |
2008年 | 79篇 |
2007年 | 90篇 |
2006年 | 63篇 |
2005年 | 66篇 |
2004年 | 40篇 |
2003年 | 43篇 |
2002年 | 37篇 |
2001年 | 56篇 |
2000年 | 26篇 |
1999年 | 28篇 |
1998年 | 26篇 |
1997年 | 16篇 |
1996年 | 13篇 |
1995年 | 16篇 |
1994年 | 9篇 |
1993年 | 17篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有1380条查询结果,搜索用时 31 毫秒
31.
Summary For RFLP mapping of R-genes, determining resistance to specific races of Phytophthora infestans in tetraploid potato, it is necessary to develop well segregating populations at the 2x level. During mapping studies, evidence was obtained that more genetic factor(s) are involved in the expression of R-genes than conventionally believed. Two experiments are described in which such an additional genetic factor was suppressing or enhancing the expression of unknown R
nand R
ifactors. R
nand R
iappeared to be present in the investigated plant material, containing R4 and R10, or in one of the susceptible crossing parents. In a third experiment, the expression and the segregation of the well known R1 gene was influenced by an additional genetic factor. In that case there were indications for a dominant suppressor. This was established by the selection of susceptible plants carrying a RFLP allele of probe GP21 closely linked to R1. In three of the four F1 populations, resulting from crosses between such susceptible plants and susceptible tester plants, resistnat progenies were found. The resistance appeared to be R1-specific. This clearly indicates that in three of the four investigated susceptible plants, the R1 gene was still present but not expressed. 相似文献
32.
Actinomycetes isolated from the organic mulch used in avocado plantations in Western Australia were studied to examine their ability to suppress Phytophthora cinnamomi. All the 1600 isolates tested inhibited the pathogen in vitro with inhibition rates of >0.5. The inhibition rates achieved by actinomycetes isolated from fresh and pathogen-infested mulch were not significantly different, but the isolates tested differed in their ability to suppress the pathogen and/or the disease. Some of the isolates that inhibited the pathogen were also harmful to plant growth. 相似文献
33.
《Communications in Soil Science and Plant Analysis》2012,43(2):229-243
Abstract Phytophthora root rot (PRR) is an important disease of alfalfa (Medicago sativa L.) in wet soils. Excess soil water (ESW) stress is required for the successful infection and development of PRR. The effects of P at 0, 40, and 80 μg.g‐1 soil and K at 0, 120, and 240 μg.g‐1 soil (in factorial combinations) on the severity of PRR or ESW stress was investigated on a PRR‐susceptible (Iroquois) and a resistant (Oneida) alfalfa cultivar in a greenhouse trial. P and K applications significantly increased the dry weight of tops prior to imposition of PRR or ESW stress. However, plants subjected to PRR or ESW stress did not respond significantly to P or K and there was no significant effect of P or K on the severity of PRR or ESW injury. The plants subjected to PRR or ESW stress had lower tissue P concentration than those under stress‐free conditions. Increasing P additions resulted in a significant increase in P concentration of Iroquois plants, while in Oneida the response was non‐significant. The response of K concentration in the plant to increasing K additions was dependant on P levels. 相似文献
34.
35.
The mechanism of action of oligochitosan, which has shown great antifungal activity against Phytophthora capsiciin vitro, was studied using 2-aminoacridone-labeled oligochitosan (2-AMAC-oligochitosan) and a gel-retardation experiment. Internalization of 2-AMAC-oligochitosan in cysts, germtubes and sporangia of P. capsici was confirmed by confocal laser scan microscopy (CLSM), and the degree of uptake depended on the incubation concentration. 2-AMAC-oligochitosan localized mainly in the cytoplasm and showed no binding to both cell wall and cell membrane. Mannose, an inhibitor for oligochitosan uptake by macrophages, could not inhibit the internalization of oligochitosan in P. capsici. The gel-retardation experiment showed that oligochitosan bound strongly to DNA and RNA of P. capsici. These results indicate that oligochitosan exerts its antifungal activity by penetrating the cell membrane and putative binding to intracellular targets such as DNA and RNA. 相似文献
36.
37.
大豆疫霉菌多聚半乳糖醛酸酶pspg1基因的克隆及表达分析 总被引:1,自引:0,他引:1
大豆疫病严重影响我同及世界各国的农业生产,为探讨多聚半乳糖醛酸酶在大豆疫霉菌致病过程中的作用,采用PCR的方法从大豆疫霉菌中克隆了多聚半乳糖醛酸酶pspg1基因,并利用RT-PCR法对其在大豆中的表达进行了分析.结果表明:大豆疫霉菌pspg1基因开放阅读框长1236 bp,编码一个长412氨基酸的蛋白质.对其进化关系进行分析,发现该基因与其它卵菌的pg基因亲缘关系最近,形成一个独立的分支.RT-PCR分析表明:pspg1基因在接种大豆疫霉菌的大豆下胚轴中大量表达,而在健康大豆下胚轴中未检测到.克隆了大豆疫霉菌pspg1基因,并发现该基因在大豆疫霉菌侵染大豆过程中发挥重要作用. 相似文献
38.
选择了5种杀菌剂,将其制成具有缓释性能的颗粒剂,施在辣椒根茎基部防治辣椒疫病。室内接种试验,有4种颗粒剂施药7d后防效100%,21d后防效95%以上。田间试验防效平均在84%以上,连续3年田间应用,防效为80%左右。 相似文献
39.
烟草黑胫病菌的田间群体分布规律 总被引:5,自引:0,他引:5
从云南省不同烟区采集不同生态条件的土壤标样,用土壤稀释平板法和叶片诱饵法分离烟草疫霉并进行群体数量及分布规律的研究。结果,不同生态的土壤中烟草疫霉群体数量及分布存在着显著的差异:连作田、低湿地、感病品种栽种地等土壤中烟草疫霉的群体数量大于轮作田、高燥地、抗病品种地等土壤中的群体数量;偏酸性土壤中的烟草疫霉群体数量较中性土壤和碱性土壤中的病菌群体数量大;根际土的烟草疫霉群体数量随距离根部的增加而减少。黑颈病田间发病率与土壤中烟草疫霉的群体数量呈正相关性。弄清土壤中烟草疫霉的群体数量及其田间群体分布规律,有助于烟草种植规划的制定、黑胫病的预测与防治。 相似文献
40.
来自中国云南、辽宁、山东3省的烟草寄生疫霉(Phytophthora parasitica var.nicotianae)菌株的致病性已被划分为3种致病类型组,即强致病性组、中致病性组和弱致性组。上述省是中国的烟草主产区,选自云南省的15个烟草寄生疫霉菌株、山东省的13个烟草寄生霉菌株和辽宁省的20个烟草寄生疫霉菌株,选择3个烟草栽培品种在温室内进行接种试验测定不同菌株的致病性分化。提取受试菌株的DNA,利用PCR技术对受试苗菌株的模板DNA进行随机多态性扩增分析,对扩增DNA片段谱带借助于UPGMA分析法构建遗传树,结果表明,受试菌株被划分为4个遗传聚类组,每个遗传聚类组内包括不同的烟草寄生疫霉致病性菌株,而且来自于不同烟区相同的致病性菌株和每种致病性的不同菌株皆不属于同一个遗传聚类组内。结果表明RAPD-PCR的遗传标记分析结果与不同致病性组的划分未有明显的区别。因此,随机多态性DNA图谱的相同与不同不能当作区分来自不同烟区的烟草寄生疫霉的致病性分化的分子检测的工具。 相似文献