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21.
N. K. Dwivedi O. P. Dhariwal S. Gopala Krishnan D. C. Bhandari 《Genetic Resources and Crop Evolution》2010,57(3):443-452
Among the 52 species reported in Cucumis, cucumber and muskmelon are the most important species, extensively cultivated by the human for consumption. Diversity has
been reported in the wild species of Cucumis from India. Considering the status of genetic erosion of the variability in the various species of Cucumis, a total of 121 germplasm accessions of five different Cucumis species were collected through three explorations in the parts of Aravalli ranges of northwestern India. The paper presents
the distribution, collection, extent of variability, associated indigenous traditional knowledge, conservation status of these
Cucumis species and prospects of their utilization in crop improvement. 相似文献
22.
Equine babesiosis, a tick transmitted haemoprotozoan disease caused by Theileria equi is globally distributed and responsible for heavy economic losses to the equine husbandry. Equids reared in endemic areas usually pick up infection at an early age and become immune tolerant throughout their life span. We studied the level of passively transferred antibodies in neonate foals born from pre-immuned mares. Latently T. equi infected pre-immuned pony and donkey mares (three each) were selected and T. equi antibody titres in neonates was monitored till 90 days post foaling (DPF) by applying Dot-ELISA on sequentially collected serum samples from foals and their dams. A very high antibody titre was observed in pre-immuned pony and donkey mares. The maximum antibody of 1:60 to 1:80 was observed in pony's and donkey's foal on 2–16 and 2–10 DPF, respectively and thereafter it declined to less than 1:20 on 63–77 and 56–63 DPF. Simultaneously parasite carrying status in neonate foals and their dam was also monitored by applying PCR on blood samples. We could demonstrate PCR amplification in dam's blood samples while no amplification was recorded in neonate's blood samples. This study indicated that new-born foals were born naïve and passively transferred immunity was transitory which wanes after 63–77 DPF. 相似文献
23.
R. S. Dwivedi 《Land Degradation \u0026amp; Development》1994,5(3):191-199
Salinization/alkalization and waterlogging have rendered a sizeable area of India's arable lands unproductive. These highly dynamic phenomena can be studied using remote sensing data collected at regular intervals. Landsat Multi-spectral Scanner data of 28 February 1975 and 9 March 1990 were interpreted visually to derive information about the spatial extent and distribution of salt-affected soils. A significant decrease in the area of salt-affected soils was noted over this period, which can be attributed to reclamation efforts by government agencies and farmers. On a large scale, i.e. 1:50000, the waterlogged area could also be mapped using a Landsat Thematic Mapper false-colour composite print. 相似文献
24.
A study of the characterization of CO2 responsiveness in Brassica oxycamp and its parents Brassica oxyrrhina and Brassica campestris was done using open top chamber technology. The response of the X. B. oxycamp (hybrid) to elevated CO2 was significantly positive in respect of photosynthesis and growth and similar to that of its parent B. campestris. X B. oxycamp and B. campestris with greater sink potential responded significantly, whereas B. oxyrrhina with a poor sink, did not respond to CO2 enrichment. Photosynthetic changes at elevated CO3 levels in the hybrid and parents are partially attributed to the CO2 effects on stomatal conductance and chlorophyll fluorescence. 相似文献
25.
26.
Summary Changes in the inorganic pyrophosphatase (EC 3.6.1.1) activity and the chlorophyll and -amino nitrogen levels were studied in excised leaves of rice (Oryza sativa L. cv. Ratna) subjected to various degrees of water stress. Chlorophyll level decreased and a-amino nitrogen level increased in the turgid leaves floating on water; these changes were accelerated when the leaves were subjected to water stress (Figs. 2, 3). The decrease with time in the activity of alkaline inorganic pyrophosphatase and the increase with time in the activity of acid inorganic pyrophosphatase in water-floated turgid leaves were accelerated following water stress (Figs. 4, 5). There was an accelerated decline in the ratios of alkaline to acid inorganic pyrophosphatase activity in stressed compared to turgid leaves (Fig. 6). It was concluded that water stress enhances the senescence of excised rice leaves and that the changes in the activities of alkaline and acid inorganic pyrophosphatases can be taken as indicators of water stress in rice leaves.Work supported by grant from the Extra Mural Research Unit, Council of Scientific and Industrial Research, New Delhi to Dr. D. Mishra. Mr. S. Dwivedi is a University Grants Commission Junior Research Fellow 相似文献
27.
Summary The effects of Cd, Co, Ni and Zn on growth and survival of Macrophomina phaseolina were studied in vitro. Cd, Ni and Co at 500 g ml–1 inhibited growth by 78.8%, 73.6% and 11.8%, respectively, after 4 days at 25 ± 1°C. The mycelial dry weight yield was enhanced by 2.1% at 100 g ml–1 Zn. The population of the pathogen declined in soil amended separately with Cd, Co, Ni and Zn. Cd (4000 mg kg–1) proved to be the most toxic, by completely inhibiting the survival of the pathogen in soil after 20 days. 相似文献
28.
Summary Only 10% of sclerotia germinated in a tarpcovered plot after 45 days of treatment while 50% of sclerotia germinated in the control plot. However, complete inhibition of sclerotia germination was not achieved. The maximum temperature recorded was 53°C, after 45 days of treatment in a tarped plot at 1 cm depth. The incidence of Acrophialophora fusispora, Aspergillus spp., Spicaria sp., and Trichoderma viride increased in soil after 45 days of the solar treatment. 相似文献
29.
Summary Genetic studies of nonnodulation in groundnut were carried out in a cross, NC 17×PI 259747, with a single Rhizobium strain, NC 92, and a native Rhizobium population.The normal nodulation of the parents, F1 generations and backcross progenies, and the F2 segregation for nodulation and nonnodulation confirmed that nonnodulation in groundnut is controlled by two duplicate recessive genes.Approved ICRISAT Journal Article No. 211. 相似文献
30.
Sangam Lal Dwivedi Suresh Pande Joginedi Narayan Rao Shyam Narayan Nigam 《Euphytica》2002,125(1):81-88
Late leaf spot (LLS) and rust cause substantial yield losses and reduce the fodder and seed quality in groundnut (Arachis hypogaea L.). Adoption of resistant cultivars by the semi-arid tropic farmers is the best option to overcome yield losses. Knowledge
on components of resistance to these diseases should facilitate the development of groundnut cultivars with enhanced resistance
to LLS and rust. The objectives of the experiments were to study the genetic variability and relationships among components
of resistance to LLS and rust, and assess their significance in disease resistance breeding. Fifteen interspecific derivatives
for LLS and 14 for rust and a susceptible control, TMV 2, were evaluated in a randomised complete block design with two or
three replications under greenhouse conditions. The experiments were repeated twice. Genotypic differences were highly significant
for all the traits studied. Resistance to LLS is due to longer incubation and latent periods, lesser lesions per leaf, smaller
lesion diameter, lower sporulation index, and lesser leaf area damage and disease score. Selection based on components of
resistance to LLS may not lead to plants with higher retained green leaf area. The remaining green leaf area on the plant
should, therefore, be the major selection criteria for resistance to LLS in breeding programs. Resistance to rust is due to
longer incubation and latent periods, fewer pustules per leaf, smaller pustule diameter, lower sporulation index, and lesser
leaf area damage and disease score. Rust resistant components appear to work additively, therefore, selection based on resistance
components together with green leaf area retained on the plant should be the basis of selecting for resistance to rust in
breeding programs. ICGV 99005, 99003, 99012, and 99015 for rust and ICGV 99006, 99013, 99004, 99003, and 99001 for LLS are
the better parents for use in resistance breeding programs.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献