Perhaps you should try some spelling variations:
cac viet » cach viet, bac viet, ca viet
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
cam tuc » cam xuc, cam tu, dam thuc
tai cac » tai cuc
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ky tang » ky nang, ky dang, kho tang
ma hoi » mai hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky tang ((ma hoi) or (xa hoi)). hieu ve ((cam tuc) or (nam thuc)) van hanh tai cac viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang ((ma hoi) OR (xa hoi)). hieu ve ((cam tuc) OR (nam thuc)) van hanh tai cac viet.
• Adding a wildcard symbol may retrieve word variants: su sach ky tang ((ma hoi) or (xa hoi)). hieu ve ((cam tuc) or (nam thuc)) van hanh tai cac viet*.