Perhaps you should try some spelling variations:
gian lan » gian lang, gian dan, giang van
te sach » toc sach
hieu va » lieu va, hieu qua
lan cua » lang cua, ban cua, lai cua
va gian » va gianh, van gian, va giai
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, sach thu
hieu ve » hieu van
ty sang » ty xang, ty hang, duy sang

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ty sang ((xa hoi) or (ma hoa)). ((hieu ve) OR (hieu va)) cao duc va gian lan cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty sang ((xa hoi) OR (ma hoa)). ((hieu ve) OR (hieu va)) cao duc va gian lan cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty sang ((xa hoi) or (ma hoa)). ((hieu ve) OR (hieu va)) cao duc va gian lan cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ty sang ((xa hoi) or (ma hoa)). ((hieu ve) OR (hieu va)) cao duc va gian lan cua tre*.