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 sao » nam giao
nam dao » nam dan, nam cao, nam da
cac xuc » cam xuc, cac nuoc, chat xuc
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
cu tren » tu tren, dua tren
ma hoi » mai hoi, xa hoi, ma hoa
va cu » va cau, va chu, va su

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) OR (nam sao)) va cu 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) OR (nam sao)) va cu 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) OR (nam sao)) va cu tren".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky nang ma hoi. hieu hieu cac xuc ((nam dao) OR (nam sao)) va cu tren*.