Perhaps you should try some spelling variations:
chat duc » chat xuc, chat doc, chet duoc
hanh lai » hanh lam, hanh tai, thanh lap
tu sach » thu sach, su sach, te sach
cua tre » cuu tre, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
mai hoi » mai khoi, dai hoi, lai hoi
ky dang » ky nang, ky danh
ky tang » ky nang, kho tang, ky trong
cua te » cua tu

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 tang) or (ky dang)) mai hoi. hieu ve chat duc va hanh lai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky tang) OR (ky dang)) mai hoi. hieu ve chat duc va hanh lai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky tang) or (ky dang)) mai hoi. hieu ve chat duc va hanh lai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky tang) or (ky dang)) mai hoi. hieu ve chat duc va hanh lai ((cua tre) OR (cua te))*.