Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
thuc ban » thuoc ban, thuc dan, thu ban
truc ban » truc dan, truc van, truoc bang
hang oi » hang doi, hang loi, hang di
su sach » vu sach
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
so sach » so sanh, bo sach, co sach
v nang » va nang, vu nang, van nang
ve cac » va cac, vien cac
oi su » ki su, vi su

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