Perhaps you should try some spelling variations:
va triet » va trien, ve triet, cua triet
dang xay » dang van, van xay
su sach » so sach, vu sach
cau loc » hau loc, cau hoc, cau luc
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
qua cau » quan cau, qua cac, qua ca
lang xa » lang ha, lang van
loc va » hoc va, luc va
thiet » thieu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((lang xa) OR (dang xay)) hoi. hieu qua cau loc va danh vi ((va triet) OR (va thiet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((lang xa) or (dang xay)) hoi. hieu qua cau loc va danh vi ((va triet) OR (va thiet))~".
• Adding a wildcard symbol may retrieve word variants: su sach y ((lang xa) or (dang xay)) hoi. hieu qua cau loc va danh vi ((va triet) OR (va thiet))*.