Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
hieu hien » bieu hien, dieu hien, chieu chien
hieu vien » hieu viec, thieu nien, hieu tieng
cau tren » cu tren, dau tren, ca tren
thanh vi » hanh vi, thanh va, thanh ve
tu sach » thu sach, te sach, tu cach
lang xa » lang ha, dang xay, lang van
ty lang » tay lang, ty xang, ty hang
su sach » so sach, vu sach
cac tu » cac thu, cach tu, cac du
tu van » tu va
vi cau » va cau, ve cau, di cau

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: ((tu sach) OR (su sach)) ty lang xa hoi. ((hieu vien) OR (hieu hien)) cac tu van thanh vi cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) ty lang xa hoi. ((hieu vien) or (hieu hien)) cac tu van thanh vi cau tren~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) ty lang xa hoi. ((hieu vien) or (hieu hien)) cac tu van thanh vi cau tren*.