Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
duc ban » duc tan, duc van, duc man
dua ban » dia ban, cua ban, qua ban
so viet » hoc viet
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
sach 2 » sach y
2 nang » v nang
x hoi » xa hoi, o hoi, x ho

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 2 nang x hoi. hieu ve cac ((duc ban) or (dua ban)) hanh vi ((su viet) OR (so viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach 2 nang x hoi. hieu ve cac ((duc ban) OR (dua ban)) hanh vi ((su viet) OR (so viet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach 2 nang x hoi. hieu ve cac ((duc ban) or (dua ban)) hanh vi ((su viet) OR (so viet))*".