Perhaps you should try some spelling variations:
dang xay » dang van, van xay
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
hanh di » hanh vi, hanh de, hang di
tuc van » thuc van, truc van, tuc va
dau tuc » dau tu, dao tuc, cau truc
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
lang xa » lang ha, lang van
cua tre » cua te, cuu tre, cua triet
va dau » va dao
di cua » dai cua, doi cua, de cua

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