Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cau tren » cu tren, dau tren, ca tren
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, dua tren
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty xang, ty hang
hieu ve » hieu va, hieu van
cam duc » cam xuc, cao duc, pham duc
ve cam » ve cham, ve cac, va cam
nang o » nang co, nang ho, nang ro
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: tu sach ty nang o hoi. hieu ve cam duc va hanh vi ((((cua tre) or (cua triet))) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang o hoi. hieu ve cam duc va hanh vi ((((cua tre) OR (cua triet))) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang o hoi. hieu ve cam duc va hanh vi ((((cua tre) or (cua triet))) or (cau tren))*.