Perhaps you should try some spelling variations:
hach toan » thanh toan, manh toan
sach hoi » sach doi, sach moi, cach thoi
cuu cong » cua cong, thu cong, cac cong
khoa hoc » hoa hoc
so sach » so sanh, bo sach, co sach
hoi tap » hoi dap, hoc tap, hoi tai
va phan » van phan, va phat, va phap
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: so sach hoi tap, nghien cuu cong ((hach toan) or (cac khoan)) khoa hoc ma hoi va phan tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach hoi tap, nghien cuu cong ((hach toan) OR (cac khoan)) khoa hoc ma hoi va phan tu.
• Adding a wildcard symbol may retrieve word variants: so sach hoi tap, nghien cuu cong ((hach toan) or (cac khoan)) khoa hoc ma hoi va phan tu*.