Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
mang xa » lang xa, mang may, dang xay
hanh di » hanh vi, hanh de, hang di
sach ty » sach y, sach tu, sach thu
dau tuc » dau tu, dao tuc, cau truc
tuc van » thuc van, truc van, tuc va
cua tu » cua tuc, cua cu, cua te
va dau » va dao
cua su » qua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((mang xa) or (nang x)) hoi. lieu va dau tuc van hanh di ((cua tu) OR (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((mang xa) OR (nang x)) hoi. lieu va dau tuc van hanh di ((cua tu) OR (cua su))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((mang xa) or (nang x)) hoi. lieu va dau tuc van hanh di ((cua tu) OR (cua su))*".