Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
dua ban » dia ban, cua ban, qua ban
duc van » duc va, duc tan, duc manh
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
v nang » va nang, vu nang, van nang
x hoi » xa hoi, o hoi, x ho
vi su » va su, ve su, ki su

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)) v nang x hoi. hieu ve cac ((duc van) or (dua ban)) hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) v nang x hoi. hieu ve cac ((duc van) OR (dua ban)) hanh vi su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) v nang x hoi. hieu ve cac ((duc van) or (dua ban)) hanh vi su triet*".