全文获取类型
收费全文 | 565篇 |
免费 | 20篇 |
国内免费 | 55篇 |
专业分类
林业 | 18篇 |
农学 | 45篇 |
基础科学 | 5篇 |
52篇 | |
综合类 | 231篇 |
农作物 | 18篇 |
畜牧兽医 | 6篇 |
园艺 | 160篇 |
植物保护 | 105篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 17篇 |
2020年 | 19篇 |
2019年 | 24篇 |
2018年 | 10篇 |
2017年 | 18篇 |
2016年 | 39篇 |
2015年 | 20篇 |
2014年 | 21篇 |
2013年 | 30篇 |
2012年 | 43篇 |
2011年 | 50篇 |
2010年 | 35篇 |
2009年 | 46篇 |
2008年 | 46篇 |
2007年 | 33篇 |
2006年 | 36篇 |
2005年 | 16篇 |
2004年 | 19篇 |
2003年 | 11篇 |
2002年 | 15篇 |
2001年 | 13篇 |
2000年 | 12篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1988年 | 4篇 |
排序方式: 共有640条查询结果,搜索用时 15 毫秒
81.
本文简单介绍了格尔木地区红提子的栽培技术,大棚栽植成活率达90%。同时表述了红提子在格尔木生长季抚育管理措施,为格尔木地区种植优质红提子提供科学依据。 相似文献
82.
本研究以超藤×刺葡萄、巨峰×燕山葡萄、巨峰×沙地葡萄、水晶×华东葡萄、白香蕉×华东葡萄及玫瑰蜜×华东葡萄6个杂交组合为试材、各母本自然授粉果实及种子为对照,对其进行研究.结果表明,6个杂交组合坐果率,分别为44.44%、46.00%、41.67%、22.22%、12.00%、10.00%.与对照相比,6个杂交组合的果实重量和大小下降,可溶性固形物含量有所上升;果皮颜色、形状、果肉质地及果肉颜色变化不大;种子千粒重差异较大,水晶×华东葡萄和白香蕉×华东葡萄后代种子千粒重增大,其他杂交组合种子千粒重降低,种子大小变化规律与千粒重变化规律相同. 相似文献
83.
百花山葡萄(Vitis amurensis Rupr. var. dissecta)野外仅见一株,是北京市重点保护濒危物种。通过比较不同消毒方法、植物生长调节剂的种类和浓度配比、生根培养基类型,建立百花山葡萄组织培养快速繁殖体系。结果表明,15%的H2O2消毒4 min的效果最好,培养基MS+0.6 mg·L-16-BA+0.3 mg·L-1NAA为愈伤组织最佳诱导培养基,培养基1/2MS+1.0 mg·L-16-BA+0.1 mg·L-1NAA有利于丛生芽的诱导,在诱导不定根时,使用1/2 WPM + 0.2 mg·L-16-BA培养基培养效果最好。采用组培快繁技术,已经获得百花山葡萄完整植株,并于室外移栽成活,为百花山葡萄这一极小种群的保存与繁殖提供了保障。 相似文献
84.
广西野生毛葡萄种质资源性状评价 总被引:1,自引:0,他引:1
为了解决生产上低产不稳产和种质创新问题,2003年至2008年,对来自广西各地的124份野生毛葡萄种质进行结实和果实等性状调查和检验分析,主要性状为:萌芽期为4月12日,开花期为5月22日,成熟期为9月4日;萌芽率44.8%,变异幅度为15%~100%;结果枝率71.7%,变异幅度为12.5%~100%;每结果枝穗数2.2穗,变异幅度为1.2~4.1穗;坐果率27.1%,变异幅度为7.1%~56.1%;单穗重84.8 g,变异幅度为13.6~296.6 g;单果重1.5 g,变异幅度为0.8~2.8 g;可溶性固形物12.3%,变异幅度为9.3%~16.5%;有种子3.3粒,变异幅度为1.8~4.2粒;出汁率71.6%,变异幅度为63.4%~80.1%;水溶性总糖11.70 g/100mL,变异幅度为6.08~18.11 g/100mL;总酸2.05 g/100mL,变异幅度为1.10~3.14 g/100mL;单宁0.27 g/100mL,变异幅度为0.09~0.64 g/100mL;维生素C 0.67 mg/100mL,氨基酸总量315.6 mg/100mL。收集到综合性状优良的两性花原生种质。 相似文献
85.
葡萄糖氧化酶对山葡萄酒陈酿过程花色苷含量的影响 总被引:1,自引:1,他引:0
以‘左山二’山葡萄酒为试验材料,研究葡萄糖氧化酶对山葡萄酒陈酿过程中总花色苷及四种单体花色苷含量的影响。本试验总花色苷含量测定采用分光光度法,单体花色苷含量的测定应用高效液相色谱技术。结果表明,山葡萄酒在80天的陈酿过程中,葡萄糖氧化酶使山葡萄酒总花色苷及二甲花翠素-3,5-双葡萄糖苷含量下降缓慢,而花青素-3,5-双葡萄糖苷、甲基花翠素-3,5-双葡萄糖苷、花翠素-3,5-双葡萄糖苷含量变化与对照无显著差异。山葡萄酒中加入0.6 mg/L葡萄糖氧化酶能显著减缓酒中总花色苷及二甲花翠素-3,5-双葡萄糖苷含量的降解速率,对提高山葡萄酒的品质具有积极作用。 相似文献
86.
Soledad Martos Anna Andolfi Jordi Luque Laura Mugnai Giuseppe Surico Antonio Evidente 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(4):451-461
In recent years an increasing number of species of Botryosphaeriaceae have been associated with grapevine decline worldwide.
Five species isolated from declining grapevines in Spain (Botryosphaeria dothidea, Diplodia seriata, Dothiorella viticola, Neofusicoccum luteum and N. parvum) were checked for toxin production in liquid cultures. Cultural conditions for all fungi were adjusted to obtain optimal
production of phytotoxic culture filtrates, by growing the fungi in steady liquid cultures of Czapek–Dox broth for different
time intervals. Phytotoxicity of D. seriata and N. parvum reached a maximum after 14 days while the remaining species showed the highest phytotoxicity levels after 21 days in culture.
All fungi produced hydrophilic high-molecular weight compounds with phytotoxic properties. In addition, N. luteum and N. parvum produced lipophilic low-molecular weight phytotoxins, not detected consistently among the remaining species. This led to
a more exhaustive study on the phytotoxicity of N. luteum and N. parvum. Culture filtrates and corresponding extracts of both species were consistently highly phytotoxic in different assays. The
gas-chromatography analysis of the acetylated O-methyl glycosides of the phytotoxic exopolysaccharides produced by N. parvum showed these substances to be composed mainly of glucose, mannose and galactose. Results suggest that phytotoxic metabolites
could be involved in the virulence of both species in planta. 相似文献
87.
88.
The effects of environmental conditions on the variability in germination dynamics of Plasmopara viticola oospores were studied from 1999 to 2003. The germination course was determined indirectly as the relative infection incidence (RII) occurring on grape leaf discs kept in contact with oospores sampled from a vineyard between March and July. The time elapsed between 1 January and the infection occurrence was expressed as physiological time, using four methods: (i) sums of daily temperatures > 8°C; (ii) hourly temperatures > 10°C; (iii) sums of hourly rates from a temperature-dependent function; or (iv) sums of these rates in hours with a rain or vapour pressure deficit ≤ 4·5 hPa (hydro-thermal time, HT). An equation of Gompertz in the form RII = exp[− a · exp(− b · HT)] produced an accurate fit for both separate years ( R 2 = 0·97 to 0·99) and pooled data ( R 2 = 0·89), as well as a good accuracy in cross-estimating new data ( r between observed and cross-estimated data were between 0·93 and 0·99, P < 0·0001). It also accounted for a great part of the variability in oospore germination between years and both between and within sampling periods. Therefore, the equation of Gompertz (with a = 15·9 ± 2·63 and b = 0·653 ± 0·034) calculated over hydro-thermal time, a physiological time accounting for the effects of both temperature and moisture, produced a consistent modelling of the general relationships between the germination dynamics of a population of P. viticola oospores and weather conditions. It represents the relative density of the seasonal oospores that should have produced sporangia when they have experienced favourable conditions for germination. 相似文献
89.
An epidemiological model simulating the growth of a single grapevine stock coupled to the dispersal and disease dynamics of the airborne conidia of the powdery mildew pathogen Erysiphe necator was developed. The model input variables were either climatic (temperature, wind speed and direction) or related to the pathogen (location and onset of primary infection). The environmental input variables dictated plant growth and pathogen spread (latent period, infection, lesion growth, conidial spore production and release). Input parameters characterized the crop production system, the growth conditions and the epidemiological characteristics of the pathogen. Output described, at each time step, number, age and pattern of healthy and infected organs, infected and infectious leaf area and aerial density of spores released. Validation of the model was achieved by comparing model output with experimental data for epidemics initiated at different times of host growth. Epidemic behaviour for two contrasting years of crop development and 7 phenological stages at the time of primary infection (PI) was examined. For PI occurring at day 115 a vine with late budbreak (1998) showed 58% of primary leaves diseased at flowering compared with only 19% for a vine with early budbreak (2003). Depending on the phenological stage at PI (1–4 leaves), the proportion of diseased primary leaves decreased from 42% to 6% at flowering. Simulations suggested that differences resulted from the interplay between the timing of the first sporulation event, the phenological stage at the time of initial infection, and the age structure and spatial distribution of the leaf population. 相似文献
90.
华东葡萄抗白粉病基因差异表达cDNA克隆与序列分析 总被引:1,自引:0,他引:1
为筛选和克隆华东葡萄抗白粉病相关基因,以高抗葡萄白粉病的华东葡萄株系白河-35-1为材料,采用mRNA差异显示(DDRT-PCR)技术进行在白粉病病原菌诱导下抗白粉病差异表达基因的研究,筛选出适宜DDRT-PCR的引物组合184对,获得抗白粉病差异表达的cDNA片段13个,序列分析结果显示其功能分别涉及转录调控、能量代谢、蛋白合成、防御反应等生理生化过程,表明华东葡萄白河-35-1抗白粉病是诸多代谢途径相互协调作用的结果。这些差异片段的获得为探明葡萄抗白粉病分子机制提供了前期理论基础。 相似文献