Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
tai cua » thai cua, tai cuc, tri cua
cham lo » cham o, cam lo, cham soc
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
ty tang » tay tang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, ma hoa, me hoi
cam o » cham o, cam lo, ca o

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach ty tang ((ma hoi) or (xa hoi)). hieu ve ((cham lo) or (cam o)) van hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ty tang ((ma hoi) OR (xa hoi)). hieu ve ((cham lo) OR (cam o)) van hanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: thuat sach ty tang ((ma hoi) or (xa hoi)). hieu ve ((cham lo) or (cam o)) van hanh tai cua tre*.