Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
van pham » san pham, van phan, van phat
cua viet » ca viet, hoa viet, cua vat
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
hieu van » hieu va, thien van, lieu va
nang ma » tang ma, sang ma, nang cao
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, ma hoa
tu sac » tu sach, tu cac, tu san

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

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