Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
vat thanh » dat thanh, gat thanh, tat thanh
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
cua viet » ca viet, hoa viet, cua vat
hoc sac » hoc sach, hoc cac, hoc mac
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sac ky nang ((ma hoi) or (ma hoa)). hieu van nam thuc vat thanh dai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sac ky nang ((ma hoi) OR (ma hoa)). hieu van nam thuc vat thanh dai cua viet.
• Adding a wildcard symbol may retrieve word variants: hoc sac ky nang ((ma hoi) or (ma hoa)). hieu van nam thuc vat thanh dai cua viet*.