Perhaps you should try some spelling variations:
thieu nien » thien nhien
hieu viec » nhieu viec, hieu ve, sieu viet
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
hanh di » hanh vi, hanh de, hang di
dau van » dao van, dam van, dau va
cac dau » cac dan, cac du, cac dai
di cua » dai cua, doi cua, de cua
y tang » ky tang, 6 tang, 5 tang
ma hoi » mai hoi, xa hoi, ma hoa
7 tang » 6 tang
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 tang) OR (7 tang)) ma hoi. ((hieu viec) or (thieu nien)) cac dau van hanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y tang) OR (7 tang)) ma hoi. ((hieu viec) OR (thieu nien)) cac dau van hanh di cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y tang) OR (7 tang)) ma hoi. ((hieu viec) or (thieu nien)) cac dau van hanh di cua te*".