Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach tham
hoang xa » hoang ha, hoang va, hoang xuan
cua viet » ca viet, hoa viet, cua vat
hieu ve » hieu van
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
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: tu ((sach thi) or (sach thieu)) hoang xa hoi. ((hieu ve) OR (hieu va)) am thuc va hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thi) OR (sach thieu)) hoang xa hoi. ((hieu ve) OR (hieu va)) am thuc va hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach thi) or (sach thieu)) hoang xa hoi. ((hieu ve) OR (hieu va)) am thuc va hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach thi) or (sach thieu)) hoang xa hoi. ((hieu ve) OR (hieu va)) am thuc va hanh vi cua viet*.