Perhaps you should try some spelling variations:
cach dung » sach dung, cach mang, tac dung
thanh hoa » thanh pho
thanh loi » thanh hai, thanh lap
cach dua » cach cua, cac du, cach de
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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 ky nang x hoi. hieu ve ((cach dua) OR (cach dung)) ban ((thanh loi) or (thanh hoa)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu ve ((cach dua) OR (cach dung)) ban ((thanh loi) OR (thanh hoa)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. hieu ve ((cach dua) OR (cach dung)) ban ((thanh loi) or (thanh hoa)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. hieu ve ((cach dua) OR (cach dung)) ban ((thanh loi) or (thanh hoa)) cua tre*.