Perhaps you should try some spelling variations:
thieu quang » hieu quang, thien quan, trien quang
cua viet » ca viet, hoa viet, cua vat
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
va cham » va chat, va tham
tu sach » thu sach, su sach, te sach
dai hoi » dai hoc, dai hai
dai moi » doi moi
vi cua » vai cua, di cua
ve cac » va cac, vien cac

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 thieu quang ((dai moi) OR (dai hoi)). hieu ((ve cac) or (va cham)) thuc va hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thieu quang ((dai moi) OR (dai hoi)). hieu ((ve cac) OR (va cham)) thuc va hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thieu quang ((dai moi) OR (dai hoi)). hieu ((ve cac) or (va cham)) thuc va hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach thieu quang ((dai moi) OR (dai hoi)). hieu ((ve cac) or (va cham)) thuc va hanh vi cua viet*.