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

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)) hoi. lieu va dau tuc van hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((nang ma) OR (lang xa)) hoi. lieu va dau tuc van hanh doi cua tre*.