Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hieu van » thien van, lieu va, hieu ve
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
cam thuc » am thuc, nam thuc, cam thu
vai cua » dai cua, hai cua, lai cua
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
ly hang » ly quang
ty hang » ty xang, thi hang, thu hang

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 ((ty hang) OR (ly hang)) xa hoi. ((hieu va) or (hieu van)) cam thuc van hanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty hang) OR (ly hang)) xa hoi. ((hieu va) OR (hieu van)) cam thuc van hanh vai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty hang) OR (ly hang)) xa hoi. ((hieu va) or (hieu van)) cam thuc van hanh vai cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty hang) OR (ly hang)) xa hoi. ((hieu va) or (hieu van)) cam thuc van hanh vai cua viet*.