Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » thien van, lieu va, hieu ve
tham soc » cham soc, tham nuoc, thai son
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va thanh, va danh
te sach » toc sach
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
soc va » hoc va, loc va, doc va

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 van) OR (hieu va)) tham soc va hanh vi ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky lang xa hoi. ((hieu van) OR (hieu va)) tham soc va hanh vi ((cua tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky lang xa hoi. ((hieu van) OR (hieu va)) tham soc va hanh vi ((cua tre) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: te sach ky lang xa hoi. ((hieu van) OR (hieu va)) tham soc va hanh vi ((cua tre) or (cau tren))*.