Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
toc sach » hoc sach, doc sach, thuoc sach
dang mat » dang vat, dang mau, dung mat
sach thu » sach thue, sach thieu, sach tham
viec dat » vien dai, vien da, viec lam
dang ma » dang mau, dang mam, tang ma
dat xuc » dat nuoc, dat duoc, chat xuc
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
o viet » so viet, hoc viet
va o » va co, va do, va mo

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