Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghe thu
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, cac khoi
nhan van » nhan dan, nhan va, phan van
tu sach » thu sach, su sach, te sach
doi tac » dong tac
hoc mai » hoc ma, hoc dai, hoc bai
khoi va » hoi va, khi va, choi va
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) OR (nghien cuu)) cong hoc thanh hoa hoc mai khoi va nhan van~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach doi tac, ((nghien thu) OR (nghien cuu)) cong hoc thanh hoa hoc mai khoi va nhan van".
• Adding a wildcard symbol may retrieve word variants: tu sach doi tac, ((nghien thu) OR (nghien cuu)) cong hoc thanh hoa hoc mai khoi va nhan van*.