Perhaps you should try some spelling variations:
sach thi » sach tai, sach thieu, sach tham
sach thu » sach thue, sach thieu, sach tham
hang doi » hang loi, huong doi, hang tai
doi hoc » doi hoac, dai hoc, hoi hoc
cac luc » cau luc, cac nuoc, cac cuoc
va hang » van hang, va nang, va lang
hang di » hang vi, hang dien, hang dich
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua

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