Perhaps you should try some spelling variations:
dua tren » dung tren
hieu va » lieu va, hieu qua
lua tre » cua tre, luy tre, luat tri
sach ly » sach y, sach lo, sach ty
tu sach » thu sach, su sach, te sach
hieu ve » hieu van
ly nang » ky nang, ly hang, ly vang
cac xuc » cam xuc, cac nuoc, chat xuc
xuc va » duc va, tuc va, luc va
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va

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 ly nang x ho. ((hieu ve) or (hieu va)) cac xuc va dan vi ((lua tre) OR (dua tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ly nang x ho. ((hieu ve) OR (hieu va)) cac xuc va dan vi ((lua tre) OR (dua tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ly nang x ho. ((hieu ve) or (hieu va)) cac xuc va dan vi ((lua tre) OR (dua tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ly nang x ho. ((hieu ve) or (hieu va)) cac xuc va dan vi ((lua tre) OR (dua tren))*.