Perhaps you should try some spelling variations:
loai tren » la tren, thai tren
hieu van » hieu va, thien van, lieu va
nam duoc » nam thuoc, da duoc, dat duoc
duoc van » duoc va, duc van, duoc ban
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
cua tre » cua te, cuu tre, cua triet

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 ky tang xa hoi. hieu van nam duoc van hanh vi ((loai tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky tang xa hoi. hieu van nam duoc van hanh vi ((loai tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: te sach ky tang xa hoi. hieu van nam duoc van hanh vi ((loai tren) or (cua tre))*.