Perhaps you should try some spelling variations:
cau quoc » cac quoc, cao quoc, han quoc
hanh hai » thanh hai, nhanh hai, hang hai
cao tang » cao dang
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
quoc ban » quoc bao, quoc lan, quoc quan
su sach » so sach, vu sach
cua tre » cuu tre, cua triet, dua tren
van cau » van dau, van hau, van chat
ky tang » ky nang, ky dang, kho tang
cua te » cua tu

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) or (cao tang)) xa hoi. hieu van cau quoc ban hanh hai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky tang) OR (cao tang)) xa hoi. hieu van cau quoc ban hanh hai ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su sach ((ky tang) or (cao tang)) xa hoi. hieu van cau quoc ban hanh hai ((cua tre) or (cua te))*.