Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hien cac » thien cac, vien cac, hieu cac
van hanh » van thanh, ban hanh, van anh
vai cua » dai cua, hai cua, lai cua
va hanh » va thanh, va danh, ban hanh
su sach » so sach, vu sach
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
cac lo » cac lop, cac co, cac bo
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 y ((nang xa) OR (lang xa)) hoi. hieu hien cac lo ((va hanh) or (van hanh)) vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (lang xa)) hoi. hieu hien cac lo ((va hanh) OR (van hanh)) vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) OR (lang xa)) hoi. hieu hien cac lo ((va hanh) or (van hanh)) vai cua te".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) OR (lang xa)) hoi. hieu hien cac lo ((va hanh) or (van hanh)) vai cua te*.