Perhaps you should try some spelling variations:
hang hai » hoang hai, hang tai, thanh hai
hanh hai » thanh hai, nhanh hai, hanh tai
kho tang » cao tang
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
xuc van » duc van, luc van, xuc ban
van cam » van nam, van lam, van cau
ky tang » ky nang, ky dang, ky trong
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) or (kho tang)) xa hoi. hieu van cam xuc van ((hanh hai) OR (hang hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ((ky tang) OR (kho tang)) xa hoi. hieu van cam xuc van ((hanh hai) OR (hang hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ((ky tang) or (kho tang)) xa hoi. hieu van cam xuc van ((hanh hai) OR (hang hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sac ((ky tang) or (kho tang)) xa hoi. hieu van cam xuc van ((hanh hai) OR (hang hai)) cua tre*.