Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
so sach » so sanh, bo sach, co sach
lang xa » lang ha, dang xay, lang van
hieu ve » hieu van
hieu va » lieu va, hieu qua
truc va » thuc va, trung va
y lang » o lang, _ lang, tay lang
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y lang xa hoi. ((hieu ve) OR (hieu va)) cam ((truc va) or (thuc vat)) hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y lang xa hoi. ((hieu ve) OR (hieu va)) cam ((truc va) OR (thuc vat)) hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y lang xa hoi. ((hieu ve) OR (hieu va)) cam ((truc va) or (thuc vat)) hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: so sach y lang xa hoi. ((hieu ve) OR (hieu va)) cam ((truc va) or (thuc vat)) hanh vi cua viet*.