Perhaps you should try some spelling variations:
hieu hieu » hien hieu, hieu hien, thien hieu
hieu cac » hieu luc, hieu va, hieu van
toc sach » hoc sach, doc sach, thuoc sach
nam dao » nam dan, nam sao, nam cao
xuc nam » duc nam, xuc cam, cuc nam
cac xuc » cam xuc, cac nuoc, chat xuc
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
va cu » va cau, va chu, va tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (toc sach)) ky nang ma hoi. hieu hieu cac xuc nam dao ((va cu) OR (va su)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) ky nang ma hoi. hieu hieu cac xuc nam dao ((va cu) OR (va su)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (toc sach)) ky nang ma hoi. hieu hieu cac xuc nam dao ((va cu) OR (va su)) tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky nang ma hoi. hieu hieu cac xuc nam dao ((va cu) OR (va su)) tren*.