Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
qua pham » quan pham, quy pham, qua cham
tinh hai » tinh thai, tinh chat, trinh han
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
tang ma » mang may, tang van
lang xa » lang ha, dang xay, lang van
va tinh » may tinh
cua tre » cua te, cuu tre, dua tren

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 ty ((tang ma) or (lang xa)) hoi. hieu qua pham duc va tinh hai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((tang ma) OR (lang xa)) hoi. hieu qua pham duc va tinh hai ((cua tre) OR (cua triet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((tang ma) or (lang xa)) hoi. hieu qua pham duc va tinh hai ((cua tre) OR (cua triet))*".