Perhaps you should try some spelling variations:
cua triet » su triet, va triet
cua viet » ca viet, hoa viet, cua vat
danh day » danh dau, dan day, doanh dao
duoc va » nuoc va, duc va, duoc ma
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
va chat » van chat, va phat, cao chat
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
doc va » hoc va, duc va, loc va

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 va chat ((doc va) OR (duoc va)) danh day ((cua triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu va chat ((doc va) OR (duoc va)) danh day ((cua triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. hieu va chat ((doc va) OR (duoc va)) danh day ((cua triet) or (cua viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu va chat ((doc va) OR (duoc va)) danh day ((cua triet) or (cua viet))*.