Perhaps you should try some spelling variations:
thanh vi » thanh va, thanh ve, nhanh vi
te sach » toc sach
cac thu » cach thuc, cac thoi
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
lang xa » dang xay, lang van
lang ha » long ha
cu tren » tu tren, dua tren
ve cac » va cac, vien cac
thu va » thuc va, thue va, tu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky ((lang xa) or (lang ha)) hoi. hieu ve cac thu va ((thanh vi) OR (hanh vi)) cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((lang xa) OR (lang ha)) hoi. hieu ve cac thu va ((thanh vi) OR (hanh vi)) cu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((lang xa) or (lang ha)) hoi. hieu ve cac thu va ((thanh vi) OR (hanh vi)) cu tren".
• Adding a wildcard symbol may retrieve word variants: te sach ky ((lang xa) or (lang ha)) hoi. hieu ve cac thu va ((thanh vi) OR (hanh vi)) cu tren*.