Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
sach thi » sach thu, sach tai, sach thieu
thanh di » thanh de, thanh do, thanh dinh
te sach » toc sach
hieu va » lieu va, hieu qua
hang ca » hang va, nang cao, hang tai
hang xa » hoang xa, hang va, lang xa
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
cam tu » cam thu, nam tu, dam tu

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 thi ((hang xa) or (hang ca)) hoi. hieu va cam tu va ((thanh di) OR (thanh doi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach thi ((hang xa) OR (hang ca)) hoi. hieu va cam tu va ((thanh di) OR (thanh doi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach thi ((hang xa) or (hang ca)) hoi. hieu va cam tu va ((thanh di) OR (thanh doi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach thi ((hang xa) or (hang ca)) hoi. hieu va cam tu va ((thanh di) OR (thanh doi)) cua tre*.