Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
su sach » so sach, vu sach
ly nang » ky nang, ly vang, ly quang
ly hang » ly quang
hieu va » lieu va, hieu qua
va hang » van hang, va nang, va lang
hang vi » hang va, hanh vi, hang di
cua tre » cua te, cuu tre, dua tren

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

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