Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
hanh hai » thanh hai, nhanh hai, hang hai
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
cac duc » cac du, cao duc, cac nuoc
cac dac » cac dan, cac dai, cac bac
su hai » su tai
hai ky » thai ky, hoi ky, hai ly

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

• Performing a fuzzy search may retrieve terms with similar spellings: su hai ky tang xa hoi. hieu ve ((cac duc) or (cac dac)) van hanh hai ((cua tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su hai ky tang xa hoi. hieu ve ((cac duc) OR (cac dac)) van hanh hai ((cua tre) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: su hai ky tang xa hoi. hieu ve ((cac duc) or (cac dac)) van hanh hai ((cua tre) or (su triet))*.