Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
ban thanh » ban hanh, ban hang
sach moi » sach hoi, bach mai, sach bai
sach doi » sach hoi, sach dao, sach bai
cong hoc » dong hoc, cong hoa, cong coc
dan hoan » van hoan, dan hoat, dan toan
hoan hoc » hoa hoc, toan hoc, hoang hoa
hoi ban » hoi dan, hoi bai, doi ban
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach moi) or (sach doi)) tap, nghien thu cong hoc dan hoan hoc ma hoi ban thanh san~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach moi) OR (sach doi)) tap, nghien thu cong hoc dan hoan hoc ma hoi ban thanh san.
• Adding a wildcard symbol may retrieve word variants: su ((sach moi) or (sach doi)) tap, nghien thu cong hoc dan hoan hoc ma hoi ban thanh san*.