Perhaps you should try some spelling variations:
thien van » thi van
loai tren » la tren, thai tren
van hanh » van thanh, ban hanh, van anh
luc van » luoc van, luu van, duc van
lam luc » lao luc, lam duoc
te sach » toc sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
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 lang xa hoi. ((hieu va) or (thien van)) lam luc van hanh vi ((loai tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky lang xa hoi. ((hieu va) OR (thien van)) lam luc van hanh vi ((loai tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: te sach ky lang xa hoi. ((hieu va) or (thien van)) lam luc van hanh vi ((loai tren) or (cua tre))*.