Perhaps you should try some spelling variations:
cua triet » su triet, va triet
cua viet » ca viet, hoa viet, cua vat
vu khanh » vu thanh, van khanh, duy khanh
hoc goc » hoc hoc, hoc nuoc, hoc duoc
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve hoc » te hoc, va hoc, vi hoc
goc va » hoc va, loc va, doc va
ma hoi » mai hoi, xa hoi, ma hoa

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 ma hoi. hieu ve hoc goc va hanh vi ((cua triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu khanh)) ky nang ma hoi. hieu ve hoc goc va hanh vi ((cua triet) OR (cua viet)).
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu khanh)) ky nang ma hoi. hieu ve hoc goc va hanh vi ((cua triet) or (cua viet))*.