Perhaps you should try some spelling variations:
thieu hang » thieu khang, thieu quang, thi hang
tham thuc » nham thuc, pham thuc, tam thuc
va triet » va thiet, va trien, cua triet
han thai » han tai, ban thai, van thai
ve triet » va trien, su triet
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
va han » va phan, van han, va hanh
co hoi » co hoc, co loi

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 hang ((co hoi) or (xa hoi)). hieu va tham thuc va han thai ((va triet) OR (ve triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thieu hang ((co hoi) OR (xa hoi)). hieu va tham thuc va han thai ((va triet) OR (ve triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thieu hang ((co hoi) or (xa hoi)). hieu va tham thuc va han thai ((va triet) OR (ve triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach thieu hang ((co hoi) or (xa hoi)). hieu va tham thuc va han thai ((va triet) OR (ve triet))*.