Perhaps you should try some spelling variations:
sach doi » sach hoi, sach moi, sach dao
doi nang » dai nang, hoi nang, voi nang
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
cua viet » ca viet, hoa viet, cua vat
su sach » so sach, vu sach
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
vi cua » vai cua, di cua
x hoi » o hoi, x ho, 5 hoi

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 doi nang ((x hoi) or (xa hoi)). hieu van nam thuc va hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach doi nang ((x hoi) OR (xa hoi)). hieu van nam thuc va hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: su sach doi nang ((x hoi) or (xa hoi)). hieu van nam thuc va hanh vi cua viet*.