Perhaps you should try some spelling variations:
hang dau » hang va, hang tai
danh dau » lanh dao, danh tu, xang dau
te sach » toc sach
sach ky » sac ky, sach y, sach ty
su viet » so viet
hieu va » lieu va
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
tuc va » thuc va, truc va, tuc xa
co tuc » co thuc, co tu, co toc

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky dang xa hoi. ((hieu va) or (hieu qua)) co tuc va ((danh dau) OR (hang dau)) su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky dang xa hoi. ((hieu va) OR (hieu qua)) co tuc va ((danh dau) OR (hang dau)) su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky dang xa hoi. ((hieu va) or (hieu qua)) co tuc va ((danh dau) OR (hang dau)) su viet".
• Adding a wildcard symbol may retrieve word variants: te sach ky dang xa hoi. ((hieu va) or (hieu qua)) co tuc va ((danh dau) OR (hang dau)) su viet*.