Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
te sach » toc sach
cham tu » pham tu, cam tu, chai tu
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
tay hoi » tay ho, tao hoi, tay thai
xay hoi » xa hoi, cay phoi, gay thoi
sach o » sach lo, sac o, sach y
tu ban » thu ban, te ban
o dang » xo dang, do dang, so dang
vi cua » vai cua, di cua

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 o dang ((xay hoi) OR (tay hoi)). hieu ve cham tu ban thanh ((vi cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach o dang ((xay hoi) OR (tay hoi)). hieu ve cham tu ban thanh ((vi cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach o dang ((xay hoi) OR (tay hoi)). hieu ve cham tu ban thanh ((vi cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: te sach o dang ((xay hoi) OR (tay hoi)). hieu ve cham tu ban thanh ((vi cua) or (dai cua)) tre*.