Perhaps you should try some spelling variations:
duc tren » duoc tren, dua tren, duc tien
hieu va » lieu va, hieu qua
sach ly » sach y, sach lo, sach ty
te sach » toc sach
hieu ve » hieu van
ly nang » ky nang, ly hang, ly vang
cac xuc » cam xuc, cac nuoc, chat xuc
va dan » ca dan, va dau, va dap
va dao » ca dao
vi duc » vu duc, oi duc, ve duc

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