Perhaps you should try some spelling variations:
va thieu » va thiet, va hieu, van hieu
tinh vai » tinh va, tinh hai, tinh bai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
va tinh » may tinh
va tieu » van tieu, vay tieu, va dieu
hieu va » lieu va, hieu qua
dai hoi » dai hoc, dai hai, dai moi
mai hoi » mai khoi, lai hoi, mai doi
xuc va » duc va, tuc va, luc va
va cam » va cham, va cac, va cao

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 ((mai hoi) or (dai hoi)). hieu va cam xuc va tinh vai ((va thieu) or (va tieu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((mai hoi) OR (dai hoi)). hieu va cam xuc va tinh vai ((va thieu) OR (va tieu)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((mai hoi) or (dai hoi)). hieu va cam xuc va tinh vai ((va thieu) or (va tieu))*.