Perhaps you should try some spelling variations:
than quoc » han quoc, tran quoc, toan quoc
thanh hoi » thanh hoai, thanh hoa, thanh hai
sach thi » sach tai, sach thieu, sach tham
sach thu » sach thue, sach thieu, sach tham
hoang ha » hoang hai, hong ha, hoang nham
hieu van » hieu va, thien van, lieu va
van than » van thanh, van thang, van tuan
ha hoi » hoa hoi, ha noi, xa hoi
cua tu » cua tuc, cua su, cua cu
gia » giao

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)) hoang ha hoi. hieu van than quoc gia thanh hoi ((cua te) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach thi) OR (sach thu)) hoang ha hoi. hieu van than quoc gia thanh hoi ((cua te) OR (cua tu)).
• Adding a wildcard symbol may retrieve word variants: te ((sach thi) or (sach thu)) hoang ha hoi. hieu van than quoc gia thanh hoi ((cua te) or (cua tu))*.