Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
vai cua » dai cua, hai cua, lai cua
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa
ve cam » ve cham, ve cac, va cam

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 ((ma hoa) or (mai hoi)). hieu ve cam ((luc va) OR (tuc va)) thanh vai cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((ma hoa) OR (mai hoi)). hieu ve cam ((luc va) OR (tuc va)) thanh vai cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((ma hoa) or (mai hoi)). hieu ve cam ((luc va) OR (tuc va)) thanh vai cua vat".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((ma hoa) or (mai hoi)). hieu ve cam ((luc va) OR (tuc va)) thanh vai cua vat*.