Perhaps you should try some spelling variations:
sai cua » dai cua, hai cua, lai cua
dan sai » danh sai, doan sai, dan tai
cac hoc » cach hoc, cac hop, bac hoc
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach kem
hieu ve » hieu van
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, sach thu
va dan » ca dan, va dao, va dau
cua te » cua tu

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 ky) or (sach ty)) lang xa hoi. ((hieu ve) OR (hieu va)) cac hoc va dan sai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach ty)) lang xa hoi. ((hieu ve) OR (hieu va)) cac hoc va dan sai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach ty)) lang xa hoi. ((hieu ve) OR (hieu va)) cac hoc va dan sai cua te".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach ty)) lang xa hoi. ((hieu ve) OR (hieu va)) cac hoc va dan sai cua te*.