| abstract |
The present application relates to a modified nucleic acid structure, as represented in general formula (I), and pharmaceutically acceptable salts or solvates thereof, the higher order structures of double helix, triple helix, and quadruple helix of the nucleic acid structure, the preparation method therefor, and the use thereof in preparing medications against viruses. R 1 -R 4 ，m 1 ，m 2 ，X，Y, and B 1 -B 5 are as defined in the description. |