Perhaps you should try some spelling variations:
dua tren » dung tren
ty nang » ky nang, ty xang, ty hang
mai hoi » mai khoi, dai hoi, lai hoi
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
han dai » phan dai, nhan dai, han tai
dai dua » dai cua, dai sua, dai luan
tu sach » thu sach, su sach, te sach
ma hoi » xa hoi, ma hoa, me hoi
ve cam » ve cham, ve cac, va cam
xuc va » tuc va, luc va, xac va

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 ty nang ((ma hoi) or (mai hoi)). hieu ve cam ((xuc va) or (duc va)) han dai dua tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((ma hoi) OR (mai hoi)). hieu ve cam ((xuc va) OR (duc va)) han dai dua tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((ma hoi) or (mai hoi)). hieu ve cam ((xuc va) or (duc va)) han dai dua tren*.