Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
hanh tai » thanh tai, hang tai, han tai
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
hoa hoi » khoa hoi, hoa hoc, hoa doi
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
ky lang » ky nang, ky dang, ky tang
tu sach » thu sach, su sach, te sach
ha hoi » ha noi, xa hoi, va hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky lang ((ha hoi) or (hoa hoi)). hieu van nam thuc va hanh tai ((cua triet) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang ((ha hoi) OR (hoa hoi)). hieu van nam thuc va hanh tai ((cua triet) OR (va triet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang ((ha hoi) or (hoa hoi)). hieu van nam thuc va hanh tai ((cua triet) or (va triet))*.