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21.
The cytological status of plantlets regenerated from shoot apical meristems of Pisum sativum was investigated. Chromosome counts in root apices of in vitro regenerated plants showed a preponderance of diploid cells. Moreover, the karyotypes of root-tips from plants derived from culture and from normal plants were basically the same. Topics such as the treatment of chromosomal armlength data, simple statistical comparison of samples derived from normal and regenerated plants are discussed. 相似文献
22.
Influence of tillage practices and nutrient management on crack parameters in a Vertisol of central India 总被引:5,自引:0,他引:5
K. K. Bandyopadhyay M. Mohanty D. K. Painuli A. K. Misra K. M. Hati K. G. Mandal P. K. Ghosh R. S. Chaudhary C. L. Acharya 《Soil & Tillage Research》2003,71(2):133-142
The frequency, size and rate of development of cracks influence the transport of water, nutrients and gases in the soil profile and plant growth processes in Vertisols. Despite their importance, studies on characterising cracks in Vertisols of India are limited. This study attempts to evaluate the influence of different tillage practices, nutrient management and cropping systems on cracking behaviour of a Vertisol in central India. The length, depth, width, area and volume of cracks were recorded after the harvest of the wet season crops, i.e. soybean (Glycine max L.) and rice (Oryza sativa L.) from three ongoing tillage experiments with three different cropping systems, i.e. soybean–wheat (Triticum aestivum L.), soybean–linseed (Linum usitatissimum L.) and rice–wheat. The results revealed that all the crack parameters were significantly negatively correlated with the water content of the 0–15 cm soil layer and, crack width and crack volume were significantly positively correlated with the bulk density of the 0–15 cm soil layer. Gravimetric water content and bulk density of the 0–15 cm soil layer together explained 79% variation in the crack volume. The crack volume was significantly negatively correlated (r=0.86,P=0.01) with the root length density of the previous soybean crop. Rice grown under puddled condition significantly enhanced different crack parameters viz., length, depth, width, surface area and volume of the cracks over nonpuddled direct seeded rice. Sub-soiling practised in soybean under the soybean–linseed system significantly reduced the width, depth, length and surface area of cracks by 12.5, 10, 5 and 12%, respectively, over conventional tillage. No tillage practised in soybean under soybean–wheat system resulted in significant increase in width, depth and volume of the cracks but decrease in length and surface area of cracks over conventional tillage and mould board tillage practice. Application of manure reduced the magnitude of different crack parameters in soybean–linseed cropping system. Thus cracking in Vertisols can be favourably managed by the selection of proper tillage practice, cropping system and organic manure amendments. 相似文献
23.
Most materials freeze when cooled to sufficiently low temperature. We find that magnetic dipoles randomly distributed in a solid matrix condense into a spin liquid with spectral properties on cooling that are the diametric opposite of those for conventional glasses. Measurements of the nonlinear magnetic dynamics in the low-temperature liquid reveal the presence of coherent spin oscillations composed of hundreds of spins with lifetimes of up to 10 seconds. These excitations can be labeled by frequency and manipulated by the magnetic fields from a loop of wire and can permit the encoding of information at multiple frequencies simultaneously. 相似文献
24.
25.
Garzione CN Hoke GD Libarkin JC Withers S MacFadden B Eiler J Ghosh P Mulch A 《Science (New York, N.Y.)》2008,320(5881):1304-1307
The surface uplift of mountain belts is generally assumed to reflect progressive shortening and crustal thickening, leading to their gradual rise. Recent studies of the Andes indicate that their elevation remained relatively stable for long periods (tens of millions of years), separated by rapid (1 to 4 million years) changes of 1.5 kilometers or more. Periodic punctuated surface uplift of mountain belts probably reflects the rapid removal of unstable, dense lower lithosphere after long-term thickening of the crust and lithospheric mantle. 相似文献
26.
Fang W Vega-Rodríguez J Ghosh AK Jacobs-Lorena M Kang A St Leger RJ 《Science (New York, N.Y.)》2011,331(6020):1074-1077
Metarhizium anisopliae infects mosquitoes through the cuticle and proliferates in the hemolymph. To allow M. anisopliae to combat malaria in mosquitoes with advanced malaria infections, we produced recombinant strains expressing molecules that target sporozoites as they travel through the hemolymph to the salivary glands. Eleven days after a Plasmodium-infected blood meal, mosquitoes were treated with M. anisopliae expressing salivary gland and midgut peptide 1 (SM1), which blocks attachment of sporozoites to salivary glands; a single-chain antibody that agglutinates sporozoites; or scorpine, which is an antimicrobial toxin. These reduced sporozoite counts by 71%, 85%, and 90%, respectively. M. anisopliae expressing scorpine and an [SM1](8):scorpine fusion protein reduced sporozoite counts by 98%, suggesting that Metarhizium-mediated inhibition of Plasmodium development could be a powerful weapon for combating malaria. 相似文献
27.
S. Kundu Ranjan Bhattacharyya Ved Prakash B.N. Ghosh H.S. Gupta 《Soil & Tillage Research》2007,92(1-2):87-95
Soil organic matter (SOM) contributes to the productivity and physical properties of soils. Although crop productivity is sustained mainly through the application of organic manure in the Indian Himalayas, no information is available on the effects of long-term manure addition along with mineral fertilizers on C sequestration and the contribution of total C input towards soil organic C (SOC) storage. We analyzed results of a long-term experiment, initiated in 1973 on a sandy loam soil under rainfed conditions to determine the influence of different combinations of NPK fertilizer and fertilizer + farmyard manure (FYM) at 10 Mg ha−1 on SOC content and its changes in the 0–45 cm soil depth. Concentration of SOC increased 40 and 70% in the NPK + FYM-treated plots as compared to NPK (43.1 Mg C ha−1) and unfertilized control plots (35.5 Mg C ha−1), respectively. Average annual contribution of C input from soybean (Glycine max (L.) Merr.) was 29% and that from wheat (Triticum aestivum L. Emend. Flori and Paol) was 24% of the harvestable above-ground biomass yield. Annual gross C input and annual rate of total SOC enrichment were 4852 and 900 kg C ha−1, respectively, for the plots under NPK + FYM. It was estimated that 19% of the gross C input contributed towards the increase in SOC content. C loss from native SOM during 30 years averaged 61 kg C ha−1 yr−1. The estimated quantity of biomass C required to maintain equilibrium SOM content was 321 kg ha−1 yr−1. The total annual C input by the soybean–wheat rotation in the plots under unfertilized control was 890 kg ha−1 yr−1. Thus, increase in SOC concentration under long-term (30 years) rainfed soybean–wheat cropping was due to the fact that annual C input by the system was higher than the required amount to maintaining equilibrium SOM content. 相似文献
28.
Developing fruits of jujube, Ziziphus mauritiana Lam., contain 2 cytokinin-like compounds, the activities of which were tested by the soybean callus test. One of them appeared to be zeatin, and this was confirmed by its behaviour in paper and column chromatography, coupled with various physicochemical tests. 相似文献
29.
S S Ghosh 《Research in veterinary science》1989,47(2):280-282
The efficacy of four vaccines in preventing Salmonella virchow infection in poultry was assessed by determining survivors after challenge, bacteriological status of tissues and excretion through stool and eggs following artificial infection in vaccinated and control birds. The study indicated that formol killed oil-adjuvant vaccine conferred the highest degree of immunity followed by gel and Freund's complete adjuvant vaccines. 相似文献
30.
S. Gandhi Doss S. P. Chakraborti S. Roychowdhuri N. K. Das K. Vijayan P. D. Ghosh 《Euphytica》2012,185(2):215-225
Sericulture is an agro-based industry, which heavily depends on mulberry (Morus spp.) for its sustainability, as mulberry leaf is the only available feed for the silkworm Bombyx mori L. Sericulture, in West Bengal and other subtropical regions in India, suffers from lack of adequate quantity of quality
mulberry leaf during the colder months, the best season for rearing the high yielding bivoltine silkworm hybrids. In order
to develop mulberry varieties, which can sustain normal growth during these colder months to yield better, efforts have been
made in different research institutes in India. The present report is part of such an effort in which accessions in germplasm
bank were screened for better growth, leaf retention and leaf yield contributing associated traits. Twenty three selected
parents were crossed, 3,500 seeds were sown, 2,700 seedlings were transplanted to progeny row trail, selected 210 hybrids
were evaluated under primary yield trial and finally nine hybrids along with a control variety were studied in detail for
all leaf yield contributing traits under final yield trial. Stability analysis was adopted to identify hybrids, which can
yield stably across seasons. The hybrids CT-44 and CT-11 out yielding the control by 17.17 and 7.11% were selected as these
hybrids yield 7.93 and 8.15 mt/ha leaf respectively during the colder months (February) for their direct use as cultivars
in West Bengal and other subtropical areas of India to sustain bivoltine sericulture to produce quality and gradable silk
fibers. 相似文献