A.三次文献 B.零次文献 C.二次文献 D.一次文献
A.Search fields B.Subjects C.Species D.Article types
A.序列数据库 B.结构数据库 C.图谱数据库 D.突变数据库 E.文献数据库
A.color and blind B.(color or colour)and blind C.colo?r and blind D.colour and blind
A.’heart attack’ B.’hip near/3 prosthesis’ C.’sleep disorder’/exp/mj/dm_dt,dm_th D.fluorouracil/dd_ae,dd_it,dd_to