Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
sach thu » sach thue, sach thieu, sach tham
nam truc » nam truoc, nam thuc, nam trung
thu hang » thi hang, thuc hanh, thu huong
hieu ve » hieu va, hieu van
hang xa » hoang xa, hang va, hang ca
va hang » van hang, va lang, va hanh
va nang » van nang, da nang, cam nang
su sach » so sach, vu sach
hai su » hai vu, lai su, hai so

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 thu hang xa hoi. ((hieu ve) or (hieu qua)) nam truc ((va hang) OR (va nang)) hai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thu hang xa hoi. ((hieu ve) OR (hieu qua)) nam truc ((va hang) OR (va nang)) hai su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thu hang xa hoi. ((hieu ve) or (hieu qua)) nam truc ((va hang) OR (va nang)) hai su triet".
• Adding a wildcard symbol may retrieve word variants: su sach thu hang xa hoi. ((hieu ve) or (hieu qua)) nam truc ((va hang) OR (va nang)) hai su triet*.