Perhaps you should try some spelling variations:
dieu hien » dieu khien, dieu kien, bieu hien
hieu hien » bieu hien, chieu chien, dieu khien
dinh vai » dinh van, dinh vi, dinh va
van dinh » van minh, van dich, va dinh
su sach » so sach, vu sach
bao van » dao van, cao van, hao van
nang xa » nang x, nang ma, mang xa
vai cua » dai cua, hai cua, lai cua
lang xa » lang ha, dang xay, lang van
sach ky » sac ky, sach y, sach ty
cac bao » cach bao, cac bai, cac ban
cua te » cua tu

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 ky ((nang xa) or (lang xa)) hoi. ((hieu hien) OR (dieu hien)) cac bao van dinh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (lang xa)) hoi. ((hieu hien) OR (dieu hien)) cac bao van dinh vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (lang xa)) hoi. ((hieu hien) OR (dieu hien)) cac bao van dinh vai cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (lang xa)) hoi. ((hieu hien) OR (dieu hien)) cac bao van dinh vai cua te*.