Perhaps you should try some spelling variations:
tinh tai » trinh tai, tinh thai, tinh hai
dang mau » dong mau, dang van, dang su
hieu ve » hieu va, hieu van
cuc tre » duc tre, cuu tre, cuc thue
luc may » truc may, phuc may
cac luc » cau luc, coc luc, cac nuoc
tu sach » thu sach, su sach, te sach
mau hoi » cau hoi, mai hoi, mau ho
ky dang » ky nang, ky danh
vu sach » vu bach, su sach, vu khach
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac

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 (vu sach)) ky dang mau hoi. hieu ve cac luc may tinh tai ((cuc tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu sach)) ky dang mau hoi. hieu ve cac luc may tinh tai ((cuc tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (vu sach)) ky dang mau hoi. hieu ve cac luc may tinh tai ((cuc tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu sach)) ky dang mau hoi. hieu ve cac luc may tinh tai ((cuc tre) OR (cua tre))*.