Perhaps you should try some spelling variations:
cao quoc » cao thuoc, han quoc, cua quoc
cac quoc » cac nuoc, cac cuoc, han quoc
thanh va » thanh van, hanh va, thanh ha
su triet » su viet, su tien, ve triet
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
gia » giao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (su sach)) ky nang xa hoi. hieu ve ((cao quoc) OR (cac quoc)) gia thanh va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang xa hoi. hieu ve ((cao quoc) OR (cac quoc)) gia thanh va su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky nang xa hoi. hieu ve ((cao quoc) OR (cac quoc)) gia thanh va su triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang xa hoi. hieu ve ((cao quoc) OR (cac quoc)) gia thanh va su triet*.