Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
va nang » van nang, da nang, cam nang
cam luc » cam xuc, cau luc
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, dua tren
hieu va » lieu va, hieu qua
nang o » nang co, nang ho, nang ro
va cam » va cham, va cac, va cao
luc va » duc va, tuc va, loc va
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (hoc sach)) va nang o hoi. hieu va cam luc va hanh di ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) va nang o hoi. hieu va cam luc va hanh di ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sach)) va nang o hoi. hieu va cam luc va hanh di ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) va nang o hoi. hieu va cam luc va hanh di ((cua tre) OR (cua triet))*.