Perhaps you should try some spelling variations:
nang hoa » nang hoat, hang hoa, nang hoc
hieu van » hieu va, thien van, lieu va
vat hanh » vat thanh, van hanh, va hanh
su triet » su viet, su tien, ve triet
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
hoa hoi » khoa hoi, hoa hoc, hoa doi
hieu ve » hieu va
hanh va » hang va, hanh vi
thuc » thu

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) or (su sach)) ky nang hoa hoi. ((hieu ve) or (hieu van)) am thuc vat hanh va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang hoa hoi. ((hieu ve) OR (hieu van)) am thuc vat hanh va su triet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang hoa hoi. ((hieu ve) or (hieu van)) am thuc vat hanh va su triet*.