Perhaps you should try some spelling variations:
thanh dan » thanh san, thanh van, thanh dat
mai khoi » mai khoa, tai khoa, cac khoi
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
mai doi » moi doi, mai hoi, mai duoc
vu pham » su pham, vu kham, v pham
y nang » ky nang, ly nang, v nang
dan su » dang su
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 y nang ((mai doi) or (mai khoi)). hieu ((vu pham) OR (vi pham)) quoc gia thanh dan su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((mai doi) OR (mai khoi)). hieu ((vu pham) OR (vi pham)) quoc gia thanh dan su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((mai doi) or (mai khoi)). hieu ((vu pham) OR (vi pham)) quoc gia thanh dan su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((mai doi) or (mai khoi)). hieu ((vu pham) OR (vi pham)) quoc gia thanh dan su triet*.