Perhaps you should try some spelling variations:
sang dai » sang tai, lang dai, sang mai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
dai hoi » dai hoc, dai hai, dai moi
hieu ve » hieu van
hieu va » lieu va, hieu qua
xuc va » tuc va, luc va, xac va
vi cua » vai cua, di cua
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 sang dai hoi. ((hieu ve) or (hieu va)) cam ((xuc va) or (duc va)) hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang dai hoi. ((hieu ve) OR (hieu va)) cam ((xuc va) OR (duc va)) hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: tu sach ky sang dai hoi. ((hieu ve) or (hieu va)) cam ((xuc va) or (duc va)) hanh vi cua te*.