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21.
Rapid socio-economic changes in some developing countries, including India, are creating new scopes for application of precision agriculture (PA). The implications of dramatic shifts for economic development, urbanization and energy consumption in some developing countries are immense. High-tech nature of traditional PA technologies developed in advanced countries created a real challenge for engineers to search suitable PA technologies for developing countries. It is expected that application of balanced soft and hard PA technologies based on the need of specific socio-economic condition of a country will make PA suitable for developing countries also.‘Soft’ PA depends mainly on visual observation of crop and soil and management decision based on experience and intuition, rather than on statistical and scientific analysis. ‘Hard’ PA utilizes all modern technologies such as GPS, RS, and VRT. Three components, namely,‘single PA technology’, ‘PA technology package’ (for the user to select one or combination) and ‘integrated PA technology’, have been identified as a part of adoption strategies of PA in the developing countries. Therefore, the objective of this paper is to find out the scope,the present status and the strategies for adoption of PA in India and in some developing countries. Application of PA in cash crop, plantation crop, etc. has been discussed. Application of some medium and low-tech PA tools such as chlorophyll meter and leaf colour chart in small farms has been included. This exhaustive review of the present status of PA in India and in some developing countries is expected to help to find out the adoption trend and direction of future research. Detailed strategy for the adoption of PA in India has also been proposed.  相似文献   
22.
Potential fly-ash utilization in agriculture: A global review   总被引:2,自引:0,他引:2  
Though in last four decades various alternate energy sources have come into the limelight, the hyperbolic use of coal as a prime energy source cannot be counterbalanced. Disposal of high amount of fly-ash from thermal power plants absorbs huge amount of water, energy and land area by ash ponds. In order to meet the growing energy demand, various environmental, economic and social problems associated with the disposal of fly-ash would continue to increase. Therefore, fly-ash management would remain a great concern of the century. Fly-ash has great potentiality in agriculture due to its efficacy in modification of soil health and crop performance. The high concentration of elements (K, Na, Zn, Ca, Mg and Fe) in fly-ash increases the yield of many agricultural crops. But compared to other sectors, the use of fly-ash in agriculture is limited. An exhaustive review of numerous studies of last four decades took place in this paper, which systematically covers the importance, scope and apprehension regarding utilization of fly-ash in agriculture. The authors concluded that though studies have established some solutions to handle the problems of radioactivity and heavy metal content in flyash, long-term confirmatory research and demonstration are necessary. This paper also identified some areas, like proper handling of dry ash in plants as well as in fields, ash pond management (i.e., faster decantation, recycling of water, vertical expansion rather than horizontal), monitoring of soil health, crop quality, and fate of fly-ash in time domain, where research thrust is required. Agricultural lime application contributes to global warming as Intergovernmental Panel on Climate Change (IPCC) assumes that all the carbon in agricultural lime is finally released as CO2to the atmosphere. It is expected that use of fly-ash instead of lime in agriculture can reduce net CO2emission, thus reduce global warming also.  相似文献   
23.
Basu U  Chaudhuri J  Alpert C  Dutt S  Ranganath S  Li G  Schrum JP  Manis JP  Alt FW 《Nature》2005,438(7067):508-511
Antibodies, which are produced by B-lineage cells, consist of immunoglobulin heavy (IgH) and light (IgL) chains that have amino-terminal variable regions and carboxy-terminal constant regions. In response to antigens, B cells undergo two types of genomic alterations to increase antibody diversity. Affinity for antigen can be increased by introduction of point mutations into IgH and IgL variable regions by somatic hypermutation. In addition, antibody effector functions can be altered by changing the expressed IgH constant region exons through IgH class switch recombination (CSR). Somatic hypermutation and CSR both require the B-cell-specific activation-induced cytidine deaminase protein (AID), which initiates these reactions through its single-stranded (ss)DNA-specific cytidine deaminase activity. In biochemical assays, replication protein A (RPA), a ssDNA-binding protein, associates with phosphorylated AID from activated B cells and enhances AID activity on transcribed double-stranded (ds)DNA containing somatic hypermutation or CSR target sequences. This AID-RPA association, which requires phosphorylation, may provide a mechanism for allowing AID to access dsDNA targets in activated B cells. Here we show that AID from B cells is phosphorylated on a consensus protein kinase A (PKA) site and that PKA is the physiological AID kinase. Thus, AID from non-lymphoid cells can be functionally phosphorylated by recombinant PKA to allow interaction with RPA and promote deamination of transcribed dsDNA substrates. Moreover, mutation of the major PKA phosphorylation site of AID preserves ssDNA deamination activity, but markedly reduces RPA-dependent dsDNA deamination activity and severely impairs the ability of AID to effect CSR in vivo. We conclude that PKA has a critical role in post-translational regulation of AID activity in B cells.  相似文献   
24.
Specificity and reversibility of interferon ganglioside interaction.   总被引:6,自引:0,他引:6  
F Besancon  H Ankel  S Basu 《Nature》1976,259(5544):576-578
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25.
Résumé Changement de capacité de production antibiotique chez mutants nouveaux deStreptomyces nigrifaciens.

Thanks are due to PrincipalS. Sinha of Agra College, Agra, for providing all facilities and to C.S.I.R., New Delhi, for award of research followship to S.G.  相似文献   
26.
Zusammenfassung Isolierung und Charakterisierung verschiedener Stoffe aus der indischen PflanzeAbroma augusta Linn.  相似文献   
27.
Summary From the seeds of safflower (Carthamus tinctorius Linn.), infected with Fusarium oxysporum f. sp. carthami, 3 toxic compounds have been isolated in quatities sufficient to cause mycotoxicosis on prolonged ingestion. 2 of these have been identified as diacetoxyscirpenol and T-2 toxin, while the third one has also been partially characterized as a 12, 13-epoxytrichothecene. Additionally, the incidence of secondary fusarial infection of healthy seeds due to contamination with the infected ones has been reported for the first time.  相似文献   
28.
Basu P 《Nature》2007,450(7169):580-581
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