Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hanh dai » hanh tai, hanh dao, vanh dai
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
hoc sach » hoc sinh, hoc cac, hoc anh
ky dang » ky nang, ky danh
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky tang, duy sang
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (hoc sach)) ((ky sang) or (ky dang)) mai hoi. hieu van nam thuc va hanh dai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (hoc sach)) ((ky sang) OR (ky dang)) mai hoi. hieu van nam thuc va hanh dai cua viet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (hoc sach)) ((ky sang) or (ky dang)) mai hoi. hieu van nam thuc va hanh dai cua viet*.