Perhaps you should try some spelling variations:
cua triet » cua viet, va triet
hieu san » hieu van, hieu sau, chieu sang
van hanh » van thanh, ban hanh, van ban
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
van anh » van thanh, tuan anh, van minh
ma hoi » mai hoi, xa hoi, ma hoa
pham » phan

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 ma hoi. hieu san pham duc ((van hanh) or (van anh)) di ((cua triet) OR (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. hieu san pham duc ((van hanh) OR (van anh)) di ((cua triet) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoi. hieu san pham duc ((van hanh) or (van anh)) di ((cua triet) OR (su triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. hieu san pham duc ((van hanh) or (van anh)) di ((cua triet) OR (su triet))*.