全文获取类型
收费全文 | 61篇 |
免费 | 0篇 |
专业分类
林业 | 9篇 |
农学 | 16篇 |
7篇 | |
综合类 | 13篇 |
农作物 | 2篇 |
水产渔业 | 5篇 |
畜牧兽医 | 5篇 |
植物保护 | 4篇 |
出版年
2024年 | 1篇 |
2022年 | 1篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2015年 | 1篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 1篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 12篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1960年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有61条查询结果,搜索用时 15 毫秒
21.
Yufang Guo Sukumar Saha John Z. Yu Johnie N. Jenkins Russell J. Kohel Brian E. Scheffler David M. Stelly 《Euphytica》2008,161(3):361-370
Bacterial artificial chromosome (BAC) libraries with large DNA fragment inserts have rapidly become the preferred choice for
physical mapping. BAC-derived microsatellite or simple sequence repeats (SSRs) markers facilitate the integration of physical
maps with genetic maps. The objective of this research was to identify chromosome locations of the BAC-derived SSR markers
in tetraploid cotton. A total of 192 SSR primer pairs were derived from BAC clones of an Upland cotton genetic standard line
TM-1 (Gossypium hirsutum L.). Metaphor agarose gel electrophoresis results revealed 76 and 59 polymorphic markers between TM-1 and 3–79 (G. barbadense) or G. tomentosum, respectively. Using deletion analysis method, we assigned 39 markers out of the 192 primer pairs to 17 different chromosomes
or chromosome arms. Among them, 19 and 17 markers were localized to A-subgenomes (chromosome 1–13) and D-subgenomes (chromosome
14–26), respectively. The subgenome status for the remaining three markers remained unclear due to their two potential chromosome
locations achieved by tertiary monosomic stocks deletion analysis. Chromosomal assignment of these BAC-derived SSR markers
will help in integrating physical and cotton genetic linkage maps and thus facilitate positional candidate gene cloning, comparative
genome analysis, and the coordination of chromosome-based genome sequencing project in cotton.
Disclaimer: Mention of trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product
by USDA, ARS and does not imply its approval to the exclusion of other products or vendors that may also be suitable.
The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged. 相似文献
22.
23.
Variability in rainfall is known to be a major influence on the dynamics of tropical forests, especially rates and patterns of tree mortality. In tropical dry forests a number of contributing factors to tree mortality, including dry season fire and herbivory by large herbivorous mammals, could be related to rainfall patterns, while loss of water potential in trees during the dry season or a wet season drought could also result in enhanced rates of death. While tree mortality as influenced by severe drought has been examined in tropical wet forests there is insufficient understanding of this process in tropical dry forests. We examined these causal factors in relation to inter-annual differences in rainfall in causing tree mortality within a 50-ha Forest Dynamics Plot located in the tropical dry deciduous forests of Mudumalai, southern India, that has been monitored annually since 1988. Over a 19-year period (1988–2007) mean annual mortality rate of all stems >1 cm dbh was 6.9 ± 4.6% (range = 1.5–17.5%); mortality rates broadly declined from the smaller to the larger size classes with the rates in stems >30 cm dbh being among the lowest recorded in tropical forest globally. Fire was the main agent of mortality in stems 1–5 cm dbh, elephant-herbivory in stems 5–10 cm dbh, and other natural causes in stems >10 cm dbh. Elephant-related mortality did not show any relationship to rainfall. On the other hand, fire-related mortality was significantly negatively correlated to quantity of rainfall during the preceding year. Mortality due to other causes in the larger stem sizes was significantly negatively correlated to rainfall with a 2–3-year lag, suggesting that water deficit from mild or prolonged drought enhanced the risk of death but only with a time lag that was greater than similar lags in tree mortality observed in other forest types. In this respect, tropical dry forests growing in regions of high rainfall variability may have evolved greater resistance to rainfall deficit as compared to tropical moist or temperate forests but are still vulnerable to drought-related mortality. 相似文献
24.
Subbiah Krishna Kumar K. M. Palanivel K. Sukumar B. Samuel Masilamoni Ronald G. Selvaraju G. Ponnudurai 《Tropical animal health and production》2018,50(4):793-799
A cross-sectional study was carried out to identify risk factors for bovine viral diarrhea virus (BVDV) infection in 62 randomly selected dairy herds which were tested for BVD serum antibodies by using an indirect ELISA kit (IDEXX). Results from the chi-square test analysis were interpreted by analyzing by chi-square test. A sum of 500 sera samples were screened and 66 animals (13.20%) showed positive for BVDV antibody. Within herd, BVD seroprevalence was 12–65%. This study concluded that epidemiological risk factors like location, herd size, housing patterns like, tail to tail system, roofing pattern, distance between the manure pit and farm, and distance between farms were significantly associated with BVDV serological status (P?<?0.05). 相似文献
25.
RASKA Dwaine A SAHA Sukumar JENKINS Johnie N MCCARTY Jack C WU Ji-xiang STELLY David M 《棉花学报》2008,(Z1)
The genetic base that cotton breeders commonly use to improve Upland cultivars is very narrow.The AD-genome species Gossypium barbadense,G.tomentosum,and G.mustelinum are part of the primary germplasm pool,too,and constitute genetic reservoirs of genes for resistance to abiotic stress,pests,and pathogens,as well as agronomic and fiber traits. 相似文献
26.
Tapan Kumar Nath Mohammed Jashimuddin Md. Kamruzzaman Vaskar Mazumder Md. Kamrul Hasan Sukumar Das 《Journal of Sustainable Forestry》2013,32(8):562-577
ABSTRACTThe Chunati Wildlife Sanctuary (CWS), a degraded protected area in southeastern Bangladesh, had been under comanagement since 2004. This study examined phytosociological characteristics and diversity of trees in CWS and discussed villagers’ opinions on the impact of comanagement on forest conservation. Following a stratified and systematic sampling 140 circular plots, 17.84-m radius each, were laid out in seven forest beats for the assessment of phytosociological characteristics and tree diversity. Several key-informant interviews and 15 focus group discussions were held to explore the impact of comanagement on forest conservation and on villagers’ livelihood. A total of 93 tree species were identified having a diameter at breast height (dbh) of ≥ 5 cm in 36 plant families. The dominant species were Acacia auriculiformis, Dipterocarpus turbinatus, Ficus hispida, and Tectona grandis. The average density of trees was 239 trees/ha of which 60% was composed of planted exotic species. Nearly 90% trees were belonging to 5- to 15-cm dbh class and the Shannon-Wiener index was 3.15. The comanagement governance had brought positive changes in forest conservation. However, to sustain the engagement of poor villagers in the comanagement and conservation of degraded CWS, more collective efforts are needed to support their living. 相似文献
27.
Kamlesh K. Meena Sukumar Mesapogu Manish Kumar Mahesh S. Yandigeri Geeta Singh Anil K. Saxena 《Biology and Fertility of Soils》2010,46(2):169-174
In this study, inoculation of the chickpea (Cicer arietinum) with the novel symbiotic fungus (Piriformospora indica) was analysed in combination with the Tn5-lacZ-tagged phosphate-solubilising bacterium Pseudomonas striata. This study aims to evaluate whether the co-inoculation of these two species would enhance the population buildup of P. striata in the rhizosphere, P uptake, growth and yield of chickpea. Single inoculation of P. indica and P. striata has a negative effect on plant growth and yield of chickpea. Data showed that the combination of the two microorganisms had
a synergistic effect on population buildup of P. striata and plant dry biomass with respect to their single inoculation. However, the P uptake was not significantly influenced by
single or combined inoculation of two species. At 20 days after sowing, the influence of combined inoculation on the population
of P. striata was positive; at 60 days after sowing, it was neutral as the populations in treatments with single and combined inoculation
were at par; and at harvest, it was negative The population of P. striata was higher at flowering stage as compared to 20 days after sowing and at harvest. 相似文献
28.
A transforming ras gene in tumorigenic guinea pig cell lines initiated by diverse chemical carcinogens 总被引:5,自引:0,他引:5
S Sukumar S Pulciani J Doniger J A DiPaolo C H Evans B Zbar M Barbacid 《Science (New York, N.Y.)》1984,223(4641):1197-1199
Fetal guinea pig cells were transformed by treatment with four different chemical carcinogens including nitroso compounds and polycyclic hydrocarbons. As a consequence of this treatment, oncogenes capable of transforming NIH/3T3 cells became activated in each of five independently established clonal guinea pig cell lines. Molecular characterization of representative NIH/3T3 transformants revealed that the same oncogene was present in each of the cell lines tested. Moreover, detection of this transforming gene paralleled the acquisition of tumorigenic properties by these neoplastic cells. 相似文献
29.
Mihai Sun Young Chul Kim Okorie Eme Okorie Seunghyung Lee Sukumar Devnath Gwangyeol Yoo Sungchul C . Bai Yong Kil Jo 《Journal of the World Aquaculture Society》2007,38(4):536-542
A 10‐wk feeding experiment was conducted to evaluate the potential use of fermented soybean curd residues (FSCR) as an energy source in diets for juvenile olive flounder, Paralichthys olivaceus. Five isonitrogenous and isoenergetic diets were formulated to contain dry soybean curd residues to replace wheat meal (WM) at the levels of 0, 25, 50, 75, and 100% (FSCR0, FSCR25, FSCR50, FSCR75, and FSCR100, respectively). Fish averaging 6.00 ± 0.07 g (mean ± SD) were randomly distributed into 15 aquaria as groups of 15 fish and fed the experimental diets in triplicate at a rate of 4–5% of wet body weight per day twice daily on dry matter basis. At the conclusion of the feeding trial, weight gain (WG) and specific growth rate (SGR) of fish fed diet FSCR25 were significantly higher than those of fish fed diets FSCR50, FSCR75, and FSCR100 (P < 0.05); however, there were no significant differences in WG and SGR among fish fed diets FSCR0 and FSCR25 and among those fed diets FSCR0 and FSCR50. Feed efficiency and protein efficiency ratio of olive flounder fed diet FSCR25 were significantly higher than those of fish fed diets FSCR50, FSCR75, and FSCR100 (P < 0.05); however, there were no significant differences in these parameters among fish fed diets FSCR0 and FSCR25 and among those fed diets FSCR0, FSCR50, FSCR75, and FSCR100. Hematological characteristics, condition factor, hepatosomatic index, and survival rate of fish fed FSCR0 were not significantly different from those of fish fed the other diets. These results indicated that FSCR could replace up to 50% WM as an energy source in juvenile olive flounder diets based on ANOVA test. 相似文献
30.
N. Vedaraman Sukumar PuhanG. Nagarajan B.V. RamabrahmamK.C. Velappan 《Industrial Crops and Products》2012,36(1):282-288
Many research reported vegetable oil as a potential substitute for diesel engines with its ester form known as biodiesel. The biodiesel can be prepared by different process using vegetable oil and alcohol. The common process used for biodiesel preparation is known as transesterification. This paper presents the transesterification of Sal oil (Shorea robusta) into Sal oil methyl ester (SOME) and its performance in direct injection diesel engine. Several process parameters such as catalyst quantity, molar ratio of alcohol, reaction temperature and reaction time were studied and the optimized process conditions are amount of catalyst (NaOH) - 0.25 wt%, alcohol (methanol) - 150% excess, reaction temperature - 65 °C and reaction time - 1.5 h. The studies with SOME as fuel in the direct injection diesel engine shows that the exhaust emissions such as CO, HC and NOx are reduced by 25%, 45% and 12%, respectively compared to diesel without significant difference in thermal efficiency. Based on this study it is concluded that the SOME can be used as fuel without any modifications in the engine and hence this biodiesel can be a potential substitute to standard diesel fuel. 相似文献