Perhaps you should try some spelling variations:
sach thue » sach thu, sach thieu, cach thuc
sach tham » sach nha
lang van » dang van, tang van, hoang van
do thai » do thi, toc thai
da thai » dao thai, ca thai, a thai
qua cac » cua cac
cac duc » cac du, cao duc, cac dac
van hoi » van hoa, van hoc, van hoe
cua tre » cua te, cuu tre, cua triet

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 thue) OR (sach tham)) lang van hoi. hieu qua cac duc va ((da thai) or (do thai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach thue) OR (sach tham)) lang van hoi. hieu qua cac duc va ((da thai) OR (do thai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach thue) OR (sach tham)) lang van hoi. hieu qua cac duc va ((da thai) or (do thai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach thue) OR (sach tham)) lang van hoi. hieu qua cac duc va ((da thai) or (do thai)) cua tre*.