Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
vu khanh » vu thanh, van khanh, duy khanh
va hanh » van hanh, va thanh, va danh
hoc goc » hoc hoc, hoc nuoc, hoc duoc
tu sach » thu sach, su sach, te sach
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
goc va » hoc va, loc va, doc va
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: ((tu sach) or (vu khanh)) ky nang xa hoi. ((hieu ve) OR (hieu van)) hoc goc va hanh vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu khanh)) ky nang xa hoi. ((hieu ve) OR (hieu van)) hoc goc va hanh vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (vu khanh)) ky nang xa hoi. ((hieu ve) OR (hieu van)) hoc goc va hanh vi cua triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu khanh)) ky nang xa hoi. ((hieu ve) OR (hieu van)) hoc goc va hanh vi cua triet*.