Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
lieu van » lieu va, hieu van, sieu van
ty nang » ky nang, ty xang, ty hang
sach ty » sach y, sach tu, sach thu
nam xuc » cam xuc, nam xua, nam thuc
va hanh » van hanh, va thanh, va danh
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, dua tren
su sach » so sach, vu sach
xuc va » duc va, tuc va, luc 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: su sach ty nang ((o hoi) or (xa hoi)). lieu van nam xuc va hanh de ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ((o hoi) OR (xa hoi)). lieu van nam xuc va hanh de ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ((o hoi) or (xa hoi)). lieu van nam xuc va hanh de ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ((o hoi) or (xa hoi)). lieu van nam xuc va hanh de ((cua tre) OR (cua triet))*.