Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
sach ty » sach tu, sach thu, xach tay
hanh di » hanh vi, hanh de, hang di
tuc van » thuc van, truc van, tuc va
dau tuc » dau tu, dao tuc, cau truc
cuu tre » cua tre, cau tren, cau treo
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
va dau » va dao
di cuu » di cau, di cua, dinh cuu

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) OR (sach y)) ((nang xa) or (nang ma)) hoi. lieu va dau tuc van hanh di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach y)) ((nang xa) OR (nang ma)) hoi. lieu va dau tuc van hanh di cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach y)) ((nang xa) or (nang ma)) hoi. lieu va dau tuc van hanh di cuu tre*".