Perhaps you should try some spelling variations:
va hanh » van hanh, va thanh, va danh
hieu ve » hieu va, hieu van
cac loc » cac lop, cac toc, cac hoc
nang ma » tang ma, sang ma, nang cao
lang xa » lang ha, dang xay, lang van
ve cac » va cac, vien cac
sai ky » sac ky
loc va » hoc va, luc va
di cuu » di cua, dinh cuu
di cau » da cau, diem cau
te sai » te tai, te bai, te lai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sai ky ((nang ma) OR (lang xa)) hoi. hieu ve cac loc va hanh ((di cuu) OR (di cau)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sai ky ((nang ma) or (lang xa)) hoi. hieu ve cac loc va hanh ((di cuu) OR (di cau)) tre~".
• Adding a wildcard symbol may retrieve word variants: te sai ky ((nang ma) or (lang xa)) hoi. hieu ve cac loc va hanh ((di cuu) OR (di cau)) tre*.