Perhaps you should try some spelling variations:
sach thue » sach thu, sach thieu, sach tham
va triet » va thiet, va trien, ve triet
cach tu » cach thuc
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
dinh di » dinh du, dinh vi, danh di
luc va » duc va, tuc va
loc va » hoc va
di va » dai va, di vao, doi va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach thue) or (cach tu)) lang xa hoi. hieu va cac ((luc va) OR (loc va)) dinh di va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach thue) OR (cach tu)) lang xa hoi. hieu va cac ((luc va) OR (loc va)) dinh di va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach thue) or (cach tu)) lang xa hoi. hieu va cac ((luc va) OR (loc va)) dinh di va triet".
• Adding a wildcard symbol may retrieve word variants: thu ((sach thue) or (cach tu)) lang xa hoi. hieu va cac ((luc va) OR (loc va)) dinh di va triet*.