Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh doi » thanh doi, hanh noi, hang doi
sach ty » sach y, sach thu, xach tay
sach tu » sach thu, cach tu, sach uu
nang xa » nang x, lang xa, nang ma
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) or (sach tu)) nang 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) OR (sach tu)) nang xa hoi. lieu va dau tuc van hanh doi cua tre*.