Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
thuc day » thuc dan, thuc vat
hanh vai » hanh vi, hanh va, hanh tai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat, trung va
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: tu sach ky nang xa hoi. hieu van cau ((truc va) or (thuc day)) hanh vai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu van cau ((truc va) OR (thuc day)) hanh vai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. hieu van cau ((truc va) or (thuc day)) hanh vai ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu van cau ((truc va) or (thuc day)) hanh vai ((cua tre) OR (cua triet))*.