Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dua tren » dung tren
va triet » va thiet, va trien, ve triet
te sach » toc sach
nang ma » tang ma, sang ma, nang cao
nam tuc » nam thuc, nam truc, nam tu
y nang » ky nang, ly nang, v nang
tuc va » thuc va, truc va, tuc xa
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
cua tu » cua tuc, cua su, cua cu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ma hoa. hieu van nam tuc va dan vi ((((dua tren) OR (cua tu))) OR (va triet))~.
• Adding a wildcard symbol may retrieve word variants: te sach y nang ma hoa. hieu van nam tuc va dan vi ((((dua tren) or (cua tu))) or (va triet))*.