全文获取类型
收费全文 | 363篇 |
免费 | 20篇 |
国内免费 | 8篇 |
专业分类
林业 | 2篇 |
农学 | 60篇 |
基础科学 | 4篇 |
68篇 | |
综合类 | 146篇 |
农作物 | 14篇 |
水产渔业 | 4篇 |
畜牧兽医 | 6篇 |
园艺 | 63篇 |
植物保护 | 24篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 10篇 |
2020年 | 11篇 |
2019年 | 13篇 |
2018年 | 9篇 |
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 13篇 |
2014年 | 15篇 |
2013年 | 27篇 |
2012年 | 29篇 |
2011年 | 30篇 |
2010年 | 12篇 |
2009年 | 18篇 |
2008年 | 14篇 |
2007年 | 32篇 |
2006年 | 17篇 |
2005年 | 8篇 |
2004年 | 12篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 7篇 |
2000年 | 8篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有391条查询结果,搜索用时 0 毫秒
181.
Summary Multiple shoot formation in cotyledonary callus of Indian mustard (Brassica juncea cv. Prakash) was induced on modified MS media supplemented with high cytokinin (kinetin or zeatin) and low IAA concentrations. Complete plants were obtained on prolonged incubation of shoots on the same medium. 6-Benzyladenine alone or in combination with IAA or NAA did not support plantlet regeneration. A total of 71 plants were transferred to greenhouse. The seed, however, could be collected from 37 plants only. The seed was sown in the field to evaluate the material for somaclonal variation in R1 generation. Data were recorded for yield, plant height, number of primary branches, siliqua number, 1,000 seed weight and oil content. Somaclonal lines showed tremendous amount of variation for all the characters studied. A number of plants in this generation showed significantly higher yield and/or other improved agriculturally important characteristics as compared to the control. A line with dwarf plant type was also identified. A number of plants were selected from this generation and carried forward to R2 generation. Most of these lines bred true in R2 generation. The material seems to be very promising for future breeding programmes. 相似文献
182.
Akshay K. Pradhan Yaspal S. Sodhi Arundhati Mukhopadhyay Deepak Pental 《Euphytica》1993,69(3):219-229
Summary Divergence of 25 accessions of Brassica juncea of Indian, CIS (Commonwealth of Independent States, former USSR) and synthetic origin was studied by D2 analysis. On the basis of divergence, ten accessions were selected and crossed in a diallel fashion without reciprocals to study the combining ability and heterosis. None of the accessions was found to be a good general combiner for all the nine quantitative characters that were studied. Significant heterosis over better parent for single plant yield was recorded in CIS x Indian and synthetic x CIS crosses (5 each) followed by Indian x synthetic types (3). The analysis of component characters showed that the mean performance of the majority of hybrids was intermediate for five out of six yield attributing traits, thus exhibiting dominance or partial dominance effect. To estimate the contribution of such yield attributing traits towards heterosis for yield, a comparison was made among three parameters viz. heterosis over mid parent (MP), better parent (BP) and better yielding parent (BYP) of the concerned hybrid. It was observed that estimation of heterosis from BYP was a more accurate method to determine the contribution of component characters towards yield heterosis than the analysis based on MP and BP. From the component character analysis, it was concluded that characters like number of primary and secondary branches, number of siliqua per plant and siliqua density contributed significantly towards heterosis in yield. Plot level yield trials of two selected hybrids (Skorospieka II x RH30 and Donskaja IV x Varuna) over two growing seasons revealed 29.4 to 91.8% heterosis over BYP. 相似文献
183.
A mutant with yellow seedcoat colour was isolated by Nayar (1968) in the mustard variety‘Rai-5′. This mutant was crossed to the national check cultivar ‘Varuna’ in order to develop improved strains with yellow seedcoat. Four such strains with yellow seeds were evaluated for their seed yield, yield components and percent oil. Two strains TM-9 and TM-17 were more productive than ‘Varuna’ in seed yield. All the yellow seeded strains showed higher oil percentage as compared to ‘Varuna’. The seedcoat in the yellow seeded strains accounts for 14-15% of the seed weight as compared to 18% in the black seeded ‘Varuna’. The higher proportion of the cotyledons and embryo accounts for the increased oil percentage in the yellow seeded types. 相似文献
184.
A. Márquez-Lema J. M. Fernández-Martínez B. Pérez-Vich L. Velasco 《Plant Breeding》2006,125(4):400-402
Successful commercial utilization of the meal by‐product of Brassica oilseed crops requires the cultivation of cultivars with low glucosinolate (GSL) content in the seeds; however, such cultivars are not yet available in Brassica carinata. The objective of the present research was to search for transgressive segregants with further‐reduced GSL content in the progeny of crosses involving four B. carinata lines with reduced GSL content (90 compared with 120 μmol/g seed in standard germplasm). The four lines were crossed following a diallel design and F2 phenotypes (F3 seed bulked) were analysed for GSL content. F2 phenotypes with a transgressive GSL content lower than the parents were identified in all crosses involving the line S2–1241, suggesting that this line carries alleles for reduced GSL content not present in the other lines. F3 : 4 lines from transgressive F2 phenotypes were evaluated for 2 years, which resulted in the selection of an F3 : 4 line with an average GSL content of 58 and 46 μmol/g seed, respectively compared with 84 and 62 μmol/g seed, respectively in S2–1241. 相似文献
185.
L. George V. Abraham D. R. Suryavanshi A. T. Sipahimalani V. T. Srinivasan 《Plant Breeding》1987,98(1):72-74
Homozygous diploids were obtained through anther culture in Indian mustard, Brassier juncea, cultivar TM-4, Seeds could be harvested from 97 such plants in the A; generation. The androgenetic lines were further selected and the yield and yield components were compared in the A4 and A5 generations, Androgenetic lines showed variations for most of the characters studied including seed oil content and fatty acid composition. However, it was possible to recover seven lines out of 25 which were equal in seed yield and three equal in oil content compared TO the anther donor parent TM-4. 相似文献
186.
铅-锌-镉复合污染物在土壤-芥菜/油菜系统中的迁移及交互作用 总被引:3,自引:1,他引:3
了解重金属复合污染物在土壤-植物系统中的迁移分配情况对污染土壤的安全利用、土壤环境质量标准的修订以及重金属污染土壤的植物修复具有重要意义。通过盆栽试验,以芥菜和油菜为例,研究了铅-锌-镉复合污染物在土壤-植物系统中的迁移分配情况。结果表明:与对照相比,复合污染条件下,芥菜和油菜体内重金属含量显著提高,且Cd含量的提高程度要远远高于Pb和Zn;芥菜和油菜对Cd的吸收达到了100 m g/kg以上,表现出超富集植物的吸收水平。重金属的富集系数大小依次为Cd>Zn>Pb,地下部富集系数要高于地上部,转运系数大小为Cd≈Zn>Pb。Pb、Zn、Cd的富集系数均随各自元素在土壤中含量增大而减小,而且表现为低含量时显著减小,高含量时缓慢减小;重金属在土壤-植物系统的迁移分配深受共存元素的影响,且在不同元素之间和不同浓度范围内表现出不同的特点。Pb、Zn、Cd在芥菜和油菜体中积累量,均与其各自在土壤中的含量成正相关;Zn和Cd对Pb的吸收积累以及Pb对Zn的吸收积累具有明显的抑制作用;Zn-Cd对Zn的吸收积累具有正的交互作用,而对Cd的吸收积累具有负的交互作用。 相似文献
187.
为探明阿维菌素在十字花科蔬菜芥蓝、叶芥菜和芜菁中的残留消解行为和安全性,建立了高效液相色谱测定3种蔬菜中阿维菌素残留量的分析方法。样品经丙酮提取,C18柱净化,高效液相色谱-紫外检测器检测,外标法定量;运用所建立的方法对阿维菌素在山东烟台、河北保定、浙江绍兴、贵州贵阳、黑龙江哈尔滨和安徽宿州6个试验点的芥蓝、叶芥菜、芜菁中的残留消解动态和最终残留量进行了研究。结果表明:阿维菌素在芥蓝、叶芥菜和芜菁中的消解速率很快,半衰期分别为0.3~0.6、2.2~3.1和0.8~1.0 d,其残留量随时间延长而递减,符合一级反应动力学方程,属易消解型农药。 相似文献
188.
G. Beese 《Journal of Agronomy and Crop Science》1991,166(3):169-180
Yield and Qualitative Characteristics of Indian Mustard ( Brassica juncea L. Czern.)
Indian mustard is required as raw material for the production of mustard. In field trials, farm trials and processing tests during several years evidence could be furnished, that the cultivation of the up to now foreign crop is possible on suitable sites in central Germany. On loess soils (soil value number more than 50) in regions with milder climatic conditions the grain yields attained in using of intensive specific cultivation methods on an average of about 30 dt/hectare. The results of the field trials confirmed by average yields of 14 16 dt/hectare in agricultural practice. The best farms attained grain yields up to 25 dt/hectare. With regard to raw material with a content of allyl mustard oil of more than 1.00 % also the demands of the food processing industry could be fulfilled by all lots produced on farms (the attained content of allyl mustard oil amounted to 1.00 1.40 %).
Climatic factors but also the observance of correct cultivation methods influence first of all the processing quality. 相似文献
Indian mustard is required as raw material for the production of mustard. In field trials, farm trials and processing tests during several years evidence could be furnished, that the cultivation of the up to now foreign crop is possible on suitable sites in central Germany. On loess soils (soil value number more than 50) in regions with milder climatic conditions the grain yields attained in using of intensive specific cultivation methods on an average of about 30 dt/hectare. The results of the field trials confirmed by average yields of 14 16 dt/hectare in agricultural practice. The best farms attained grain yields up to 25 dt/hectare. With regard to raw material with a content of allyl mustard oil of more than 1.00 % also the demands of the food processing industry could be fulfilled by all lots produced on farms (the attained content of allyl mustard oil amounted to 1.00 1.40 %).
Climatic factors but also the observance of correct cultivation methods influence first of all the processing quality. 相似文献
189.
190.
应用HS-SPME方法对新鲜雪里蕻及其腌菜的挥发性组分萃取取样,然后分别手动进样用TRACEMASS色一质连用仪,自动进样用Varian Soturn2000 GC-IT-MS离子阱质谱对挥发性组分进行了分离鉴定,结果皆鉴定出116个组分。其中一些成分在两台质谱仪上都有检出,这其中包括硫醚类组分4个,醛类组分12个,酮类组分5个,醇类组分4个,酯类组分11个,异硫氰酸酯类组分4个,腈类组分2个,从实验检测结果可以推断,在雪里蕻中,芥子苷结构式中的R=-CH2-CH=CH2、-CH2-CH2-CH2-CH3、-C2H4-G6H5,且雪里蕻中的芥子苷主要是烯丙基硫代葡萄糖苷,即R=-CH2-CH=CH2。 相似文献