Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hanh vai » hanh vi, hanh va, hanh tai
vai cua » dai cua, hai cua, lai cua
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ty hang » ly hang, ty xang, thi hang
ty sang » ty xang, duy sang, thu sang
tuc va » thuc va, truc va, duc va
ve cam » ve cham, ve cac, va cam

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