cccdnacovalent closed circular dnacovalently closed circular dna共价: covalence闭环: closed loop; closed cycledna: DNA = 1.deoxyribonucle ...共价闭环 dna: cccdna; covalently closed circular dna共价闭环DNA: cccdna; covalently closed circular dna下载手机词典可随时随地查词查翻译