Perhaps you should try some spelling variations:
khoa hoi » khoan hoi, khoa hoc, khoa doi
thuc dan » thuc hanh, hoc dan, thuc vat
dan hanh » dang hanh, dan khanh, dan thanh
hanh tai » thanh tai, hang tai, han tai
cua viet » ca viet, hoa viet, cua vat
ky lang » ky nang, ky dang, ky tang
hoa hoi » hoa hoc, hoa doi, hoc hoi
hieu le » hieu ve, hieu he, hieu ly
tai cua » thai cua, tai cuc, tri cua
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
a thuc » am thuc, va thuc, ha thuc
le a » le va, le ta, le ha

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky lang ((hoa hoi) or (khoa hoi)). hieu le a thuc dan hanh tai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky lang ((hoa hoi) OR (khoa hoi)). hieu le a thuc dan hanh tai cua viet.
• Adding a wildcard symbol may retrieve word variants: te sac ky lang ((hoa hoi) or (khoa hoi)). hieu le a thuc dan hanh tai cua viet*.