Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
nang dai » nang dau, nang tai, lang dai
danh vai » danh sai, danh va, doanh van
cam thuc » am thuc, nam thuc, can thuc
cua viet » ca viet, hoa viet, cua vat
va nang » van nang, da nang, cam nang
dai moi » doi moi, dai hoi
so sanh » do sanh
cam thu » nam thu, cac thu, ca thu
va danh » va dinh, va dan, va hanh
vai cua » dai cua, hai cua, lai cua
hieu ve » hieu va, hieu van

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc sach) or (so sanh)) va nang dai moi. hieu ve ((cam thuc) or (cam thu)) va danh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (so sanh)) va nang dai moi. hieu ve ((cam thuc) OR (cam thu)) va danh vai cua viet.
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (so sanh)) va nang dai moi. hieu ve ((cam thuc) or (cam thu)) va danh vai cua viet*.