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61.
为建立冬小麦开花期生长状况的遥感监测方法和技术,结合2011-2013年定点观测试验,以环境减灾卫星HJ-1A/1B数据为遥感影像源,着重分析了样本试验区冬小麦开花期主要生长指标间及其与籽粒品质、产量和卫星遥感变量间的定量关系,分别构建及评价基于HJ-1A/1B影像遥感变量的开花期叶面积指数、生物量、SPAD值和叶片含氮量监测模型。结果表明,在冬小麦开花期,作物氮反应指数(NRI)、绿色归一化植被指数(GNDVI)可分别作为监测冬小麦叶面积指数和生物量的敏感遥感变量,结构加强色素植被指数(SIPI)和SIPI可作为监测冬小麦SPAD值和叶片含氮量的敏感遥感变量,所构建的遥感监测模型可靠,模型的决定系数(r2)分别为0.73、0.69、0.62和0.61,均方根误差(RMSE)分别为0.79、1 068kg·hm-2、4.66和0.42%。利用遥感数据绘制的冬小麦开花期主要生长指标遥感监测等级分布空间量化表达图与实际相符。  相似文献   
62.
植物种子共轭亚麻酸含量分析   总被引:4,自引:0,他引:4  
以栝楼、3个石榴品种(三白玉、青皮软籽和甜绿子)和6个苦瓜品种(长白、满优青、槟城一号、开化白苦瓜一号、开化白苦瓜二号和青丰)的种子为材料分析其脂质组成和共轭亚麻酸含量.结果表明:所分析的植物种子脂质组成中最主要的为甘油三酯.其质量分数在92.6%到97.0%之间;栝楼籽油主要的脂肪酸为油酸(22.6%)、亚油酸(32.6%)和石榴酸(32.6%).而总的共轭亚麻酸(conjugated linolenic acid,CLNA)质量分数为36.9%;石榴籽中石榴酸质量分数高达73.4%~77.5%,总的CLNA 质量分数迭83.4%~87.9%;苦瓜籽α-桐酸质量分数高达56.0%~63.7%,总的CLNA质量分数达65.2%~71.9%.研究结果表明这些植物种子富含CLNA,其中栝楼籽和石榴籽中主要的CLNA为石榴酸,而苦瓜籽中主要的CLNA为α-桐酸.  相似文献   
63.
The effects of two diets with different lipid composition (squid Loligo gahi and one commercial pellet for breeders) on reproductive performance and egg lipid composition of brill (Scophthalmus rhombus) were compared. A total of 36 adult brill weighing 1482 ± 432 g were randomly distributed in the experimental tanks. A flow‐through system composed of four tanks with 4.2 m2 of bottom area (5.0 m3 × 1.2 m water depth) was used. The experiment lasted for approximately 5 months (168 days). From the four mature females fed squid, three ovulated. Five females fed pellets matured and ovulated. Total ovulations were of 10 and 44, by the three females fed squid and the five ovulating female fed pellets respectively. Egg viability was higher, although not significantly, for females fed pellets. This indicates that pellets could be a better food for breeding females. In general, the egg total lipid content and the lipid classes composition did not seem to be affected by diet. In contrast, results indicate that not only diets but also individual females, regardless of the diet consumed, are determinant for egg fatty acid composition, clearly modulating their composition.  相似文献   
64.
Fluctuating asymmetry is the random deviation from perfect bilateral symmetry owing to developmental perturbation, proposed as an indicator of sublethal environmental effects. This was measured in perch (Perca fluviatilis L.) from an acidic aluminium-rich lake. Eleven paired meristic and morphometric characters were scored for fluctuating asymmetry. Level of fluctuating asymmetry differed significantly between year classes for two of the meristic characters, lower extra gill rakers and upper extra gill rakers, and also for an index summarizing number of asymmetric meristic characters per individual. This year class variation in fluctuating asymmetry is probably due to large variation in water quality during early development of perch embryos in spring. For future work on fluctuating asymmetry on fish we recommend the use of as many year classes as possible in the analyses.  相似文献   
65.
松嫩平原光稃茅香种群生殖分蘖株数量特征分析   总被引:21,自引:7,他引:14  
在松嫩平原天然割草场光稃茅香种群的籽实成熟期,将广泛取样的588个生殖分蘖株样本分为10个高度级进行测定,分析的结果表明,株高与花序长度,营养生物量,生殖生物量,总生物量,籽粒千粒重均呈显著的正相关,与生殖生长比率,生殖分配I,生殖分配Ⅱ,每个花序种子生产的数量,结实率均呈显著的负相关,生殖分蘖株数量特征的生态可塑性及其规律性变化,蕴涵着个体生长与生殖策略。  相似文献   
66.
黄土高原天然草地根系主要参数的分布特征   总被引:13,自引:0,他引:13  
采用土钻法对黄土高原天然草地群落根系的垂直分布特征进行调查研究,同时用根系扫描仪EPSONTWAINPRO(32bit)和专业的根系形态学和结构分析应用系统WINRhizo对根系长度、根系表面积和根系体积等主要根系参数进行分析。结果表明,在15个均匀分布的采样点上,同一深度上不同径级根系之间不存在显着差异。不同径级根系的主要根系分布参数具有相似的分布规律。所有径级的根系都集中分布在表层40cm的土层中,在40cm以下的土层中根系分布相对较少。在所有径级的根系中,直径范围在0.2~0.6mm之间的根系具有最大的分布值。  相似文献   
67.
Opening address     
Abstract

The 291 preliminary land types in the Karoo Region formed the basis for the demarcation of the 144 Reasonably Homogeneous Farming Areas (RHFAs). The land types were firstly reduced to 23 Floristic Climatic Regions (FCRs) according to character species for certain macroclimatic conditions. The character species were identified by means of computer classification and ordination techniques (PHYTOTAB, TWINSPAN and DECORANA). About 22 soil forms and numerous soil series were found in the Karoo Region. Based on differences in the inherent veld production potential and erodibility of the different soils, as well as differences in slope, nine Veld Soil Potential Classes (VSPCs) were synthesised. The land types in each of the FCRs were, lastly, consolidated according to their similarity in terms of macrocli mate and dominant topographical units and VSPCs, into RHFAs.  相似文献   
68.
Black spruce (Picea mariana) trees have needles that persist for a number of years, and it is not clear which age class should be evaluated for photosynthesis to best understand physiological responses. Moreover, the impact of sampling current versus older foliage is rarely acknowledged in published literature, even though it may influence the interpretation of results. We compared the photosynthesis rate of current and 1-year-old foliage of black spruce natural regeneration during three growing seasons. The photosynthesis rate was consistently greater for 1-year-old needles compared to current-year needles at the beginning of each growing season; however, after about 1 month, rates were similar between the two age classes. This same pattern was repeated every season and was independent of light availability induced by different harvesting treatments. We suggest that photosynthesis measurements of black spruce should be performed on 1-year-old needles instead of current-year foliage to ensure more uniform photosynthesis values throughout the season.  相似文献   
69.
马占相思人工林不同年龄阶段水源涵养功能及其价值研究   总被引:8,自引:2,他引:8  
对马占相思人工林3个不同年龄阶段(4,7a和11a)的林冠层、林下植被层、枯枝落叶层、林地土壤持水量和渗透性能以及它们随林分年龄的变化规律进行了比较分析。研究结果表明,林分地上部分持水量的大小顺序为11a生(52.86t/hm^2)〉7a生(41.90t/hm^2)〉4a生(25.78t/hm^2),其趋势是随林龄的增大而增加,林地土壤(0~40cm)持水量和渗透性能也有相同的变化趋势;4,7a和11a林分的总持水量即地上部分与林地土壤的持水总量分别为2048.8,2200.3,2313.3t/hm^2,林分水源涵养总价值分别为1372.70,1474.42元/hm^2和1549.91元/hm^2。因此,马占相思人工林对改善土壤结构、提高水源涵养功能都有良好的作用。  相似文献   
70.
湖南绅士是中国近代史上极具典型意义的特殊社会群体。近代湖南绅士虽分布于全省各地 ,但又呈现出其独特的地域性特征 ,它不仅与各地的政治、经济、文化的发展程度有着较大的关系 ,而且还受湘军和各时期的领袖人物的影响甚大 ,从而造成了近代湖南绅士分布极不均匀的现象。绅士的分布不均 ,直接导致了湖南近代的政治、经济和文化呈现畸形发展的态势 ,绅士相对集中的地区政治空气浓厚 ,经济发展较快 ,文化教育事业相对繁荣 ;而绅士分布薄弱的地区 ,政治空气沉闷 ,经济发展迟缓 ,文化教育事业落后。  相似文献   
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