Perhaps you should try some spelling variations:
bao thanh » ban thanh, dao thanh, bac thanh
hieu van » hieu va, thien van, lieu va
cau quoc » cac quoc, cao quoc, han quoc
quoc bao » quoc oai, hoc bao, quoc va
su sach » so sach, vu sach
ky tang » ky nang, ky dang, kho tang
van cau » van dau, van hau, van chat
cua tre » cuu tre, cua triet, dua tren
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 dang)) xa hoi. hieu van cau quoc bao thanh san ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky tang) OR (cao dang)) xa hoi. hieu van cau quoc bao thanh san ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su sach ((ky tang) or (cao dang)) xa hoi. hieu van cau quoc bao thanh san ((cua tre) or (cua te))*.