Perhaps you should try some spelling variations:
loai tren » la tren, thai tren
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
ky lang » ky dang, ky tang, tay lang
van lam » van nam
lam luc » lao luc, lam duoc
luc van » luoc van, luu van, duc van
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) OR (ky nang)) xa hoi. hieu 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) OR (ky nang)) xa hoi. hieu van lam luc van hanh vi ((loai tren) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ky lang) OR (ky nang)) xa hoi. hieu van lam luc van hanh vi ((loai tren) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: te sach ((ky lang) OR (ky nang)) xa hoi. hieu van lam luc van hanh vi ((loai tren) or (cua tre))*.