Perhaps you should try some spelling variations:
hanh hai » thanh hai, nhanh hai, hanh tai
hang hai » hoang hai, hang tai, thanh hai
kho tang » cao tang
cam quoc » cac quoc, cao quoc, nam quoc
quoc ban » quoc bao, quoc lan, quoc quan
cua tre » cua te, cuu tre, cua triet
ky tang » ky nang, ky dang, ky trong
hieu ve » hieu va, hieu van
su sac » su sach, su cac, su xac
ve cam » ve cham, ve cac, va cam

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 ve cam quoc ban ((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 ve cam quoc ban ((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 ve cam quoc ban ((hanh hai) or (hang hai)) cua tre*.