Perhaps you should try some spelling variations:
hang hai » hoang hai, hang tai, thanh hai
hanh tai » thanh tai, hang tai, han tai
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, cao duc, pham duc
duc ban » duc tan, duc van, dua ban
tang xa » trang xa, tang ma, lang xa
hieu ve » hieu va
ky tang » ky nang, ky dang, kho tang
sac ky » cac ky, sai ky
su sac » su sach, su cac, su xac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky tang xa hoi. ((hieu ve) OR (hieu van)) cam duc ban ((hanh tai) or (hang hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky tang xa hoi. ((hieu ve) OR (hieu van)) cam duc ban ((hanh tai) OR (hang hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky tang xa hoi. ((hieu ve) OR (hieu van)) cam duc ban ((hanh tai) or (hang hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sac ky tang xa hoi. ((hieu ve) OR (hieu van)) cam duc ban ((hanh tai) or (hang hai)) cua tre*.