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

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