Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
hieu cua » hieu qua, dieu cua, bieu cua
van hanh » ban hanh, van anh, van ban
dang xay » dang van, van xay
sach ty » sach y, sach tu, sach thu
te sach » toc sach
mang xa » lang xa, mang may, mang cua
cac tu » cac thu, cach tu, cac du
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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 sach ty ((mang xa) OR (dang xay)) hoi. hieu cua cac tu ((van hanh) OR (van thanh)) vi cua tu~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty ((mang xa) OR (dang xay)) hoi. hieu cua cac tu ((van hanh) or (van thanh)) vi cua tu~".
• Adding a wildcard symbol may retrieve word variants: te sach ty ((mang xa) OR (dang xay)) hoi. hieu cua cac tu ((van hanh) or (van thanh)) vi cua tu*.