全文获取类型
收费全文 | 106篇 |
免费 | 4篇 |
国内免费 | 5篇 |
专业分类
林业 | 9篇 |
农学 | 7篇 |
基础科学 | 1篇 |
38篇 | |
综合类 | 25篇 |
农作物 | 9篇 |
水产渔业 | 3篇 |
畜牧兽医 | 12篇 |
园艺 | 7篇 |
植物保护 | 4篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 1篇 |
2011年 | 7篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 9篇 |
2007年 | 12篇 |
2006年 | 5篇 |
2005年 | 11篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1991年 | 1篇 |
排序方式: 共有115条查询结果,搜索用时 31 毫秒
1.
Comparison of Single,Averaged, and Pooled Urine Protein:Creatinine Ratios in Proteinuric Dogs Undergoing Medical Treatment 下载免费PDF全文
S. Shropshire J. Quimby R. Cerda 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2018,32(1):288-294
Background
Monitoring urine protein:creatinine ratios (UPC ) in dogs with protein‐losing nephropathy (PLN ) is challenging because of day‐to‐day variation in UPC results.Hypothesis/Objectives
Determine whether single, averaged, or pooled samples from PLN dogs receiving medical treatment yield comparable UPC s, regardless of degree of proteinuria.Animals
Twenty‐five client‐owned PLN dogs receiving medical treatment.Methods
UPC ratios were prospectively measured in each dog utilizing 3 methods: single in‐hospital sample (day 3), average sample (days 1–3), and pooled sample (equal pooling of urine from days 1–3). Bland‐Altman analysis was performed to evaluate agreement between methods for all dogs, as well as in subgroups of dogs (UPC ≤4 or UPC >4).Results
For all dogs, Bland‐Altman log‐transformed 95% limits of agreement were ?0.07–0.18 (single versus pooled UPC ), ?0.06–0.16 (single versus average UPC ), and ?0.06–0.04 (pooled versus average UPC ). For dogs with UPC ≤4, Bland‐Altman 95% limits of agreement were ?0.42–0.82 (single versus pooled UPC ), ?0.38–0.76 (single versus average UPC ), and ?0.27–0.25 (pooled versus average UPC ). For dogs with UPC >4, Bland‐Altman 95% limits of agreement were ?0.17–2.4 (single versus pooled UPC ), ?0.40–2.2 (single versus average UPC ), and ?0.85–0.43 (pooled versus average UPC ).Conclusions and Clinical Importance
UPC ratios from all methods were comparable in PLN dogs receiving medical treatment. In PLN dogs with UPC >4, more variability between methods exists likely because of higher in‐hospital results, but whether this finding is clinically relevant is unknown.2.
[目的]研究蒙古栎材积生长的变异性。[方法]对7株蒙古栎材积生长的株内和株间变异性进行分析,拟合经验生长方程和理论生长方程。[结果]蒙古栎材积生长株间变异在幼龄期不明显,随时间增加而增大,生长速率稳定后,差异性存在且稳定增加。蒙古栎材积生长在株内的变异性较小,幼龄期至生长期生长速率加快,变异性有所增加,生长稳定后,差异性存在且稳定。[结论]蒙古栎在生长过程中材积变化受外界因素的干扰较小,可较准确预测未来几年的材积生长状况。 相似文献
3.
2013年3月,我国首次出现了人感染H7N9的禽流感疫情,给我国卫生、动物疫病防治与经济健康发展带来了严峻挑战.基于近年来禽流感等流感病毒造成的严重危害,从流感病毒的病原学、分类命名、致病性、变异特性、培养特性、临床诊断、疫苗和药物防治研究进展等方面进行了综述,以期为流感病毒的深入研究和防治提供参考. 相似文献
4.
检测种质资源的多样性对于利用和有效管理种质非常重要。本研究对87份世界来源的扁穗雀麦种质利用常用的9个形态-农艺性状进行了统一田间评价。结果表明,所有采用的性状变异系数均表现出高度的变异,尤其以单株干物质产量、分蘖数和叶宽的变异幅度最大。反映株型大小的各性状之间呈显著相关,茎粗和第一节间长与其余8个性状之间存在显著相关(P0.01),旗叶宽与倒二叶宽的正相关性最强(r=0.912,P0.01)。主成分分析(PCA)表明前2个主成分可以解释总变异的74%。反映株型大小的性状以及分蘖数可能是扁穗雀麦种质形态变异的主要来源。基于欧氏距离的UPGMA聚类分析将供试材料分成3个主要的类群,第一类群具有最大的株型表现,茎干粗壮,旗叶和倒二叶宽大,分蘖数中等;第二类群具有中等的株型;第三类群具有较小的株型,叶片短而窄,但分蘖数较多。聚类分析很好地支持了前2个主成分分值的二维散点图的结果。总之,本研究表明扁穗雀麦是一种在西南平原和丘陵地区适应性极强的禾草,其表型多样性对于品种选育和资源收集具有重要的参考价值。 相似文献
5.
6.
Sexton, Z.S., Hughes, T.J., and Wise, K.A. 20XX. Analyzing isolate variability of Macrophomina phaseolina from a regional perspective. Crop Protection. XX:XXXX. Charcoal rot of soybean (Glycine max L.), caused by Macrophomina phaseolina (Tassi) Goid, has been reported more frequently in the north–central United States in recent years. Growth of isolates collected from the northern and southern U.S. was compared in vitro under various incubation temperatures, and isolate pathogenicity was assessed on cultivars adapted to each region. Results indicate that northern isolates had increased growth at 15 °C compared to isolates from southern states, while southern isolates grew 23% more at 40°C compared to northern isolates. Isolates from both regions were pathogenic on charcoal rot resistant and susceptible cultivars adapted for each region. This is the first research to suggest the importance of screening germplasm under regional environmental conditions and with local or regionally adapted isolates when evaluating cultivar resistance to charcoal rot. 相似文献
7.
Within-field variations in plant-available soil nitrogen (N) are likely to be affected by differences in soil characteristics. To study this, a 3- year field investigation was conducted during 1998-2000 on a 15 ha arable field in Sweden with considerable within-field soil texture variability. In 34 plots soil N uptake by crops, net nitrogen mineralization (Nm) during the growing season and soil mineral N in spring and shortly after harvest were determined. Beside these parameters, topography, soil organic matter content (SOM), clay content, pH(H 2 O) and grain yield were recorded. The variations in Nm were considerably large both within the field and between years. The within-field variation in Nm could partly be explained by the variation in SOM and clay content (adjusted coefficient of determination = 0.23, P <0.001). The pattern in Nm differed between years, partly because of seasonal variations in soil moisture. For these reasons, the pattern of Nm is difficult to predict without seasonal adjustments. 相似文献
8.
免耕精密播种机由于在高茬硬地作业 ,一般都在较高位投种 ,加上硬茬地开沟阻力变化较普通耕耙地相对较大 ,作业速度稳定性低 ,从而造成投种后的粒距变异系数比普通地精播机大 ,合格指数低。笔者设计的曲线导种管 ,经过优化设计计算 ,投种时的水平速度受排种速度影响最小 ,且接近播种机作业速度 ,提高了投种的一致性 ,降低了粒距变异系数 ,已应用在 2BQYF— 6A气压式硬茬精密播种机上 相似文献
9.
Variability of the seeds and cones and key taxonomic characters selection ofLarix in Northeast China
The paper presents the results of biometrical study of the seeds and cones of larch taxa from Northeast of China. Fourteen
characters are considered and their analyses showed that the seeds and cones of the larch taxa were relative greatly variable.
Cluster analysis and principal component analysis for all 6 larch taxa were made. The analysis results proved that the dominant
larch population in Toudao Farm fell within the range of variation ofLarix olgensis. The key taxonomic characters are the length of seed wing, length of cone, length of seed, the length/width ratio of seed
and number of scales.
This research was supported by Natural Science Foundation of Heilongjiang Province.(C9515)
Responsible Editor: Chai Ruihai 相似文献
10.
Strawberry (Fragaria × ananassa Duch.) is rich source of dietary antioxidants, minerals and nutrients. Dietary antioxidants have been known as beneficial for enhancing the fitness, preventing certain diseases and even mitigating the effects of ageing. The objectives of the present study were to determine variability and inheritance of antioxidants, to identify antioxidant rich and productive genotypes, and to suggest suitable breeding approaches. The genotypes, namely Ofra, Chandler, Festival and Camarosa showed higher concentrations of dietary antioxidants and therefore could be useful in future breeding. Results indicate that the effect of the genotypes on antioxidant contents is stronger than that of the environment. The high heritability (>80%) and low genetic advance as percentage of mean (<40%) for ascorbic acid and β-carotene contents could be improved by heterosis breeding. However, selection and hybridization would be effective tools to enhance the phenols and anthocyanin content, and yield potential as these traits showed high heritability (>80%) and high genetic advance as percentage of mean (>40%). Positive direct effect on fruit yield was highest for phenol content (0.609) which is also fairly close to its correlation coefficient (0.765) indicating that a direct selection based on phenol content would be most effective and that the phenol content could be used as a reliable biochemical marker to identify the productive genotypes having higher amounts of dietary antioxidants. The information could also be used for developing antioxidant rich cultivars, i.e. ‘Breeding Strawberry for High Antioxidants’. 相似文献