全文获取类型
收费全文 | 99篇 |
免费 | 5篇 |
国内免费 | 7篇 |
专业分类
林业 | 4篇 |
农学 | 2篇 |
12篇 | |
综合类 | 47篇 |
农作物 | 5篇 |
水产渔业 | 11篇 |
畜牧兽医 | 11篇 |
园艺 | 6篇 |
植物保护 | 13篇 |
出版年
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 12篇 |
2011年 | 6篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1991年 | 1篇 |
排序方式: 共有111条查询结果,搜索用时 15 毫秒
71.
亚洲薄荷内生真菌多样性研究 总被引:1,自引:0,他引:1
采用纯培养的方法对广西所采50株健康亚洲薄荷150茎段、350片叶子中分离纯化内生真菌。用形态学分类鉴别方法依据产孢内生真菌在标准培养基的菌落颜色、菌落形态及孢子的着生方式进行鉴定。部分不产孢内生真菌利用促孢培养基培养结合分子生物技术对不产孢子内生真菌进行比对鉴定。结果从亚洲薄荷中分离出481株内生真菌,隶属1纲5目6科20属。丛梗孢科Moniliaceae是其优势科,其中拟青霉属Paecilomyces、轮枝孢属Verticillium、枝顶孢属Acremonium为主要菌群,分别占11.88%、7.92%和8.91%。叶子明显以叶点霉属Phyllosticta(17.21%)、小齿梗霉属Rhinotrichum(13.49%)、黑团孢属Nigrospora(11.16%)、枝顶孢属Acremonium(10.70%)为优势菌株,而茎则以拟青霉属Paecilomyces(18.60%)、轮枝孢属Verticillium(13.95%)为优势菌株。表明亚洲薄荷内生真菌具有丰富的多样性,其中拟青霉菌属是其优势菌落,其中还分离培养到枝顶孢属内生真菌,拟青霉菌和枝顶孢属菌物有抗菌活性,和薄荷的抗菌活性是否有联系还需进一步研究。 相似文献
72.
青海省河南县草地车前物候期对气候变化的响应 总被引:2,自引:0,他引:2
根据青海省河南县牧业气象试验站1997~2018年草本植物车前物候观测数据及同期气象观测数据,研究了气候变化对车前萌芽期、黄枯期及生长期的影响。结果表明:(1)河南县近22a年平均气温呈显著上升趋势,降水量呈增多趋势,气候暖湿化特征明显;(2)车前萌芽期呈略提前趋势,平均每10a提前1.8d,车前萌芽期主要受3~4月平均气温和4月日照时数影响;(3)车前黄枯期呈极显著推迟趋势,平均每10a推迟约16.3d,8~9月平均气温升高和9月日照时数减少导致车前黄枯期明显推迟;(4)气候变暖变湿后,4~10月平均气温升高、夏季降水量增多及秋季日照时数减少是导致车前生长期延长的主要气候因子。说明气候暖湿化有利于植物物候期的延长和草地生态环境的好转,有利于草地生态环境保护和治理工程项目的实施。 相似文献
73.
[目的]探寻平车前多糖对羟自由基(.OH)和超氧阴离子自由基(O2-.)的清除作用。[方法]在热水浸提、分离纯化获取平车前多糖的基础上,构建"邻二氮菲-Fe2+氧化法产生羟自由基"和"邻苯三酚自氧化反应产生超氧阴离子自由基"的反应体系,通过紫外可见分光光度法研究平车前多糖对体系中产生的羟自由基(.OH)和超氧阴离子自由基(O2-.)的清除作用。[结果]平车前多糖对羟自由基和超氧阴离子自由基均具有一定的清除作用,并在不同浓度范围内对自由基的清除作用呈上升趋势。[结论]平车前多糖具有一定的抗氧化作用。 相似文献
74.
75.
[目的]研究车前草不同提取物的抗菌活性,比较提取物的抗菌能力。[方法]将车前草以8种不同溶剂进行室温提取,采用分光光度比浊法测定不同提取物在96孔板中对3种细菌的抗菌活性。[结果]抗菌活性最好的是车前草无水乙醇提取物(P0.05),乙醚提取物和无水甲醇提取物次之,自来水和超纯水提取物没有抗菌活性。[结论]车前草的不同溶剂提取物均具有一定的抗菌活性,对金黄色葡萄球菌和大肠杆菌的抑制作用最为明显,对绿脓杆菌的抑制作用也较好。 相似文献
76.
Effective population size (Ne) is a critical indicator of the vulnerability of a population to allele loss via genetic drift, and it can also be used to assess the evolutionary potential of a population. While some plant conservation plans have focused on outcrossing through cross-pollination as a way to increase estimated Ne, variance in reproductive output determined by ecological factors such as competition can also strongly affect estimated Ne. We examined the effects of intraspecific and interspecific competition, stressful soils, and local adaptation on estimates of Ne in an annual plant species. While ecological influences on plant growth rate variance have been predicted to influence estimates of Ne/N, we found a significant effect on the estimate of Ne/N, but no significant ecological effects on growth rate variance. Lower survivorship on stressful soil was the most important effect reducing estimates of Ne/N. If stochastic mortality is greater in environments that are abiotically stressful, then populations in these stressful environments may be slower to adapt because of lower census sizes and reduction of Ne/N. In populations of conservation concern, increasing survivorship may be of greater benefit for maximizing Ne than the reduction of variability in reproductive output among surviving adults. 相似文献
77.
78.
Chamroon Maneewan Apichai Mekbungwan Wasin Charerntantanakul Kohsho Yamauchi Koh‐en Yamauchi 《Animal Science Journal》2014,85(5):569-574
To investigate the effects of Centella asiatica (L.) on growth performance, nutrient digestibility and blood composition in piglets, 32 nursery pigs were fed 0.0, 0.5, 1.0 and 2.0% dietary C. asiatica (L.) from 15 to 90 kg BW. At 30 kg BW, nutrient digestibility was measured and at 35 kg BW piglets were vaccinated with Mycoplasma hyopneumoniae. Hematological parameters were checked at 40 and 80 kg BW. Compared with the control, growth performance was not affected. The ether extract, ash and calcium digestibility were lower at 0.5%, and dry matter, crude protein, crude fat, phosphorus and energy digestibility were lower at 1.0% (P < 0.05). On hematological values, at 40 kg hematocrit, total white blood cells, neutrophils, eosinophils, basophils, monocytes and lymphocytes were higher at the 2.0% level (P < 0.05). Most of these values except basophils and monocytes continued until at 80 kg, at which total white blood cells, neutrophils, eosinophils and lymphocytes were higher even at 1.0% (P < 0.05); neutrophil‐to‐lymphocyte ratio tended to be higher at 2.0% (P < 0.03). Cholesterol, triglycerides and antibody levels against M. hyopneumoniae did not differ except that at 40 kg the cholesterol of 0.5% was lower (P < 0.05) and M. hyopneumoniae‐specific antibodies tended to be higher with increasing levels of C. asiatica (L.) (P < 0.07). The result that C. asiatica (L.) could not improve growth performance but increased values of serum hematocrit and white blood cells, and mycoplasma immunity to M. hyopneumoniae might suggest that C. asiatica (L.) has no function to elevate body weight but has the potential to enhance innate immunity. 相似文献
79.
研究不同密度对江西车前产量及其构成因素的影响以及产量与产量构成因素的相关性。结果表明,在8.0-13.6422万株/hm^2范围内,车前产量随着密度的增大而增加;超过13.6422万株/hm^2,则产量呈下降趋势。通过二次曲线拟合得出车前高产栽培最适密度为13.6422万株/hm^2。 相似文献
80.