Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
tinh ve » trinh ve, tinh ven, dinh ve
va tinh » may tinh
cac duc » cac du, cao duc, cac dac
te sach » toc sach
sach ky » sac ky, sach y, sach ty
tay hoi » tay ho, tao hoi, tay thai
xay hoi » xa hoi, cay phoi, gay thoi
ky dang » ky nang, ky danh
hieu ve » hieu va
ve su » va su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky dang ((xay hoi) or (tay hoi)). ((hieu ve) OR (hieu van)) cac duc va tinh ve su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky dang ((xay hoi) OR (tay hoi)). ((hieu ve) OR (hieu van)) cac duc va tinh ve su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky dang ((xay hoi) or (tay hoi)). ((hieu ve) OR (hieu van)) cac duc va tinh ve su triet".
• Adding a wildcard symbol may retrieve word variants: te sach ky dang ((xay hoi) or (tay hoi)). ((hieu ve) OR (hieu van)) cac duc va tinh ve su triet*.