Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
tham thuc » nham thuc, tam thuc, thai thuc
cua viet » ca viet, hoa viet, cua vat
dang may » mang may, dang xay, dung may
hanh vai » hanh vi, hanh va, hanh tai
ban hanh » ban hang
vai cua » dai cua, hai cua, lai cua
hieu va » hieu qua
may hoi » may thoi, tay hoi, mai hoi
ky dang » ky nang, ky danh
sac ky » cac ky, sai ky
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 dang may hoi. ((hieu va) or (lieu va)) ((tham thuc) OR (pham thuc)) ban hanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky dang may hoi. ((hieu va) OR (lieu va)) ((tham thuc) OR (pham thuc)) ban hanh vai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky dang may hoi. ((hieu va) or (lieu va)) ((tham thuc) OR (pham thuc)) ban hanh vai cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sac ky dang may hoi. ((hieu va) or (lieu va)) ((tham thuc) OR (pham thuc)) ban hanh vai cua viet*.