Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
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 cac » van hac, van cau, van bac
doan vi » doan va, don vi, doan thi
cac tu » cac thu, cach tu, cac du
dan vi » don vi, dan va, gan vi

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 cac tu va ((dan vi) or (doan vi)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu van cac tu va ((dan vi) OR (doan vi)) cua triet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu van cac tu va ((dan vi) or (doan vi)) cua triet*.