Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
viec dat » vien dai, vien da, viec lam
sach thu » sach thue, sach thieu, sach tham
toc sach » hoc sach, doc sach, thuoc sach
dang mau » dong mau, dang van, dang su
dang ma » dang mam, dang mat, tang ma
xuc van » duc van, luc van, xuc ban
vuc van » duc van, luc van, thuc van
o viet » so viet, hoc viet
vi o » vi mo, vi do, voi o

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach thu ((dang ma) or (dang mau)) hoi. hieu viec dat ((xuc van) OR (vuc van)) hanh vi o viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thu ((dang ma) OR (dang mau)) hoi. hieu viec dat ((xuc van) OR (vuc van)) hanh vi o viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach thu ((dang ma) or (dang mau)) hoi. hieu viec dat ((xuc van) OR (vuc van)) hanh vi o viet".
• Adding a wildcard symbol may retrieve word variants: toc sach thu ((dang ma) or (dang mau)) hoi. hieu viec dat ((xuc van) OR (vuc van)) hanh vi o viet*.