Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
ban hanh » ban hang
cua viet » ca viet, cua vat, cua dieu
hanh vai » hanh vi, hanh va, hanh tai
thuc ban » thuoc ban, thuc dan, thu ban
va nham » va cham, va tham, va nha
may hoi » may thoi, tay hoi, mai hoi
hieu va » lieu va, hieu qua
sac ky » cac ky

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sai ky)) mang may hoi. hieu va nham thuc ban hanh vai ((cua viet) OR (hoa viet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sac ky) or (sai ky)) mang may hoi. hieu va nham thuc ban hanh vai ((cua viet) OR (hoa viet))~".
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (sai ky)) mang may hoi. hieu va nham thuc ban hanh vai ((cua viet) OR (hoa viet))*.