Perhaps you should try some spelling variations:
hieu thien » hieu hien, chieu chien, dieu khien
thien cac » hien cac, thien cau, thieu cac
su triet » su viet, su tien, ve triet
tinh doi » trinh doc, trinh do, tinh hoc
va triet » va thiet, va trien, ve triet
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cac tac » cac toc, cac bac, cac dac
nang xa » nang x, lang xa, nang ma
tinh di » trinh di, tinh da, tin di

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang xa hoi. hieu thien cac tac da ((tinh di) OR (tinh doi)) ((va triet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang xa hoi. hieu thien cac tac da ((tinh di) OR (tinh doi)) ((va triet) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang xa hoi. hieu thien cac tac da ((tinh di) OR (tinh doi)) ((va triet) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang xa hoi. hieu thien cac tac da ((tinh di) OR (tinh doi)) ((va triet) or (su triet))*.