Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
hoc thanh » hoc nhanh, hoan thanh, hoc phan
thanh hoa » thanh pho
sach doi » sach hoi, sach moi, sach dao
cong hoc » dong hoc, cong hoa, cong coc
mai khoi » mai khoa, tai khoa, dai khoa
cac khoi » cac thoi, cac khoan, cach thoi
nhan van » nhan dan, nhan va, phan van
tu sach » thu sach, su sach, te sach
doi tac » dong tac
va nhan » van nhan, ca nhan, va phan

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach doi tac, nghien thu cong hoc thanh hoa hoc ((mai khoi) or (cac khoi)) va nhan van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach doi tac, nghien thu cong hoc thanh hoa hoc ((mai khoi) OR (cac khoi)) va nhan van.
• Adding a wildcard symbol may retrieve word variants: tu sach doi tac, nghien thu cong hoc thanh hoa hoc ((mai khoi) or (cac khoi)) va nhan van*.