全文获取类型
收费全文 | 207篇 |
免费 | 20篇 |
国内免费 | 26篇 |
专业分类
林业 | 18篇 |
农学 | 33篇 |
基础科学 | 14篇 |
59篇 | |
综合类 | 58篇 |
农作物 | 12篇 |
水产渔业 | 40篇 |
畜牧兽医 | 9篇 |
植物保护 | 10篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 16篇 |
2016年 | 12篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 16篇 |
2012年 | 8篇 |
2011年 | 15篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 8篇 |
2007年 | 14篇 |
2006年 | 12篇 |
2005年 | 12篇 |
2004年 | 6篇 |
2003年 | 9篇 |
2002年 | 6篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有253条查询结果,搜索用时 31 毫秒
81.
许明辉 《云南农业大学学报(自然科学版)》1991,6(1):52-55
应用SDS电泳对云南省12个地州35个小麦地方品种高分子量谷蛋白亚基进行了分析,并测定其微量SDS沉淀值,在所有材料中发现4种带型,其亚基组成缺少与烘烤品质正相关的3+9亚基;1亚基的频率比华北地区品种低,但7亚基远远较高;所有的品种沉淀值偏低,建议在品质改良中应注意引入具有3+9亚基和沉淀值高的品种作杂交亲本。 相似文献
82.
根据我国集约化猪场排粪方式和粪水的特性,提出了采用人工清粪方式、固液分离机+沉淀+UASB+SBR+水生植物塘的污水处理工艺和猪粪(渣)堆沤发酵生产有机肥的粪污处理新工艺。经上海市嘉定种畜场污水处理工程实践证明:在保证污水全面达标排放和猪粪(渣)无害化处理的前提下,新工艺比常规工艺节约工程投资35%、节约运行电费65%左右,经济效益好。 相似文献
83.
DENG Zhi-ying ZHAO Liang LIU Bin ZHANG Kun-pu CHEN Jian-sheng QU Hou-lan SUN Cai-ling ZHANG Yong-xiang TIAN Ji-chun 《中国农业科学(英文版)》2013,(12):2125-2133
To evaluate the possible genetic interrelationships between flour components and the sedimentation volume(SD),a doubled haploid(DH) population comprising 168 lines were used to identify the conditional quantitative trait loci(QTLs) for SD in three environments.Ten additive QTLs and 15 pairs of epistatic QTLs were detected for SD through unconditional and conditional QTL mapping.Three major additive QTLs were detected for SD conditioned on the seven quality traits.Two additive QTLs were found to be independent of these traits.Three additive QTLs were suppressed by three of the seven traits because of non-detection in unconditional mapping.Three pairs of epistatic QTLs were completely affected by the seven traits because of detection in unconditional mapping but no-detection in conditional mapping.Twelve pairs of epistatic QTLs were detected in conditional mapping.Our results indicated that conditional mapping could contribute to a better understanding of the interdependence of different and closely correlated traits at the QTL molecular level,especially some minor QTLs were found.The conditional mapping approach provides new insights that will make it possible to avoid the disadvantages of different traits by breeding through molecular design. 相似文献
84.
为分析周边进水沉淀池配水槽各种常用设计方法的实际效果,采用计算流体力学(computational fluid dynamics,CFD)方法对直径为20m沉淀池进水槽进行了三维稳态模拟,比较了各种设计方法下配水孔的配水、配泥质量流量的均匀性,模拟以Eulerian-Eulerian multiphase model中的均匀混合连续流体模型(homogeneous model)为框架,包含配水槽中的水、污泥颗粒和水面上部的大气三相,设计方法选择了工程实践中常用的变槽宽定孔径、变槽宽变孔径、定槽宽定孔径和定槽宽变孔径4种配水槽设计方法。模拟结果显示:4种配水槽设计方法中各配水孔质量流量的标准差最小在10%左右,变槽宽的等流速设计整体来说配水、配泥相对均匀,可以考虑优先采用;变孔径设计孔径变化很小,但当采用等槽宽设计时,配水、配泥质量流量的均匀性改善明显。 相似文献
85.
86.
Pinpointing erosional ‘hot spots’ or sediment source areas within a watershed can be difficult because of the highly non-linear and episodic nature of effective runoff and sediment transport. Continuous monitoring of stream networks can provide insight into sediment source areas not possible from routine sampling by capturing episodic events and integrating entire storm events. This paper presents the results of a three-year study of spring snowmelt runoff in watersheds of Lake Tahoe, California, USA, using a network of nine nephelometric turbidometers. We estimate that montane badlands, comprising 1.2% of the Ward Creek watershed (25 km2), contributed 10–39% of snowmelt-derived suspended sediment load. The badlands are comprised of poorly-vegetated and deeply-incised gullies formed in parent material of Miocene volcanic mudflow breccia. The larger (29.5 km2) Blackwood Creek watershed also showed high relative erosion rates from volcanic terrain. Tributaries draining forested granitic and metasedimentary headwater regions had minimal sediment loads. Monitoring networks indicated that temporary main channel storage regulated release of fine sediment eroded from steep headwater slopes. This lag between erosion and delivery may lead to underestimation of gully erosion contribution to sediment budgets. 相似文献
87.
88.
小麦一些高分子量麦谷蛋白亚基对SDS沉降值的效应分析 总被引:1,自引:0,他引:1
分析了两个单交组合(烟农19×皖麦48和烟农19×安农0016)的F2单株、F3株系SDS沉降值和高分子量麦谷蛋白亚基(HMW-GS)组成.结果表明,高分子量麦谷蛋白亚基对SDS沉降值的影响显著.Glu-A1和Glu-B1位点内的差异对沉降值的作用达显著或极显著水平,但Glu-A1与Glu-B1的互作效应不显著.两个杂交组合亚基的等位变异对SDS沉降值的影响大小顺序为:Glu-A11>Null,Glu-B17 9= Glu-B117 18> Glu-B114 15,F2代单株和F3代株系分析结果相似. 相似文献
89.
乌龟温室养殖水中悬浮颗粒物的沉降特性 总被引:1,自引:1,他引:0
养殖水体中固体颗粒物的沉降特性对养殖池和沉淀池的优化设计非常重要。在乌龟温室养殖中期,取距池底 10 cm处的养殖水作为沉淀原样进行静态沉淀试验,测得原样的悬浮颗粒物质量浓度为(763±15.3) mg/L,粒径分布范围是1~300 μm,其中粒径>100 μm的颗粒物体积占20.4%,50~100 μm的占39.1%,<50 μm的占40.5%。结果表明:在一定的深度范围内颗粒物沉淀速率不受沉淀池深度影响,但若沉淀池太浅且颗粒物浓度较高时会发生拥挤和压缩沉淀;对于乌龟养殖中期的水体,确定了沉淀池的溢流速率和颗粒物去除率之间的关系,当溢流速率为0.0167 cm/s,悬浮颗粒物的去除率为24.9%,且溢流出的水体中总体积90%的颗粒物粒径<98.4 μm,50%的颗粒物粒径<41.9 μm;在龟鳖温室养殖池中设置平流式沉淀池可有效地进行悬浮颗粒物的管理和去除,且随着养殖水体中细微颗粒物的增加,溢流速率可随之减小。 相似文献
90.
Higher grain yield and higher grain protein deviation underline the potential of hybrid wheat for a sustainable agriculture
下载免费PDF全文
![点击此处可从《Plant Breeding》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Patrick Thorwarth Hans P. Piepho Yusheng Zhao Erhard Ebmeyer Johannes Schacht Ralf Schachschneider Ebrahim Kazman Jochen C. Reif Tobias Würschum Carl Friedrich Horst Longin 《Plant Breeding》2018,137(3):326-337
Grain yield and protein content are traits of major importance in wheat breeding, but their combination is challenging due to a tight negative correlation. Protein yield and grain protein deviation have been proposed as selection criteria to simultaneously improve both traits. Sedimentation volume is an indicator of protein quality, which plays an important role for bread‐making quality in wheat. All these traits have been investigated in our study with 135 parental inbred lines, their 1,604 hybrids and 10 commercial check varieties evaluated at five environments. The focus of our study was to investigate the usefulness of the grain protein deviation and to define a bivariate model for calculating the grain protein deviation. Further, we compared line and hybrid wheat for grain yield and quality‐related parameters such as protein content and sedimentation volume. The grain protein deviation determined with a bivariate model delivered robust estimates of variance components and enabled a balanced selection of genotypes with improved protein content and grain yield across different quality classes. Although heterosis for protein content and sedimentation volume was negative, hybrids had a higher grain protein deviation as well as higher grain yield at a given sedimentation volume or a given protein content than line varieties. 相似文献