Perhaps you should try some spelling variations:
thanh dong » thanh duong, thanh cong, hanh dong
hoc thanh » hoc nhanh, hoan thanh, hoc phan
dong duoc » dong quoc, dong duong, trong duoc
van thanh » ban thanh, van tuan
sach hoi » sach doi, sach moi, cach thoi
duoc mai » duoc ma, duoc dai, duoc hai
tu sach » thu sach, su sach, te sach
hoi tap » hoi dap, hoc tap, hoi tai
cuu mon » cuu mo, cuu mot, cuu cong
mon hoc » toan hoc, dong hoc
mai hoi » mai khoi, dai hoi, lai hoi
va phan » van phan, va phat, va phap

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 hoi tap, nghien cuu mon hoc thanh dong duoc mai hoi ((va phan) or (van thanh)) van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoi tap, nghien cuu mon hoc thanh dong duoc mai hoi ((va phan) OR (van thanh)) van.
• Adding a wildcard symbol may retrieve word variants: tu sach hoi tap, nghien cuu mon hoc thanh dong duoc mai hoi ((va phan) or (van thanh)) van*.