Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
khang di » hang di, khang vi, khang voi
truc van » thuc van, truc ban, truc dan
truc va » thuc va, thuc vat, trung va
su sach » so sach
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
vu sach » vu bach, vu khach
v nang » va nang, vu nang, van nang
ve cac » va cac, vien cac
di su » doi su, ki su, da 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 (vu sach)) v nang xa hoi. hieu ve cac ((truc van) or (truc va)) khang di su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) v nang xa hoi. hieu ve cac ((truc van) OR (truc va)) khang di su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (vu sach)) v nang xa hoi. hieu ve cac ((truc van) or (truc va)) khang di su triet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (vu sach)) v nang xa hoi. hieu ve cac ((truc van) or (truc va)) khang di su triet*.