Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
thu sach » tu sach, thuat sach, thuoc sach
ty nang » ty xang, ty hang, ly nang
hieu ve » hieu va, hieu van
cac tu » cac thu, cach tu, tac tu
va dau » va dao
dau vi » dau ve, dau va, dat vi
vi cua » vai cua, di cua

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

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