Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
hanh vai » hanh vi, hanh va, hanh tai
sach ky » sac ky, sach y, sach ty
nam dua » nam da, nam mua, nam qua
cu tren » tu tren, dua tren
ma hoi » mai hoi, xa hoi, me hoi
vai cu » vai cua, van cu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang ((ma hoi) or (ma hoa)). hieu van ((nam dua) or (nam cua)) ban hanh vai cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((ma hoi) OR (ma hoa)). hieu van ((nam dua) OR (nam cua)) ban hanh vai cu tren.
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((ma hoi) or (ma hoa)). hieu van ((nam dua) or (nam cua)) ban hanh vai cu tren*.