Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
toan phan » thanh phan, toan ban, hoa phan
cong coc » cong cuoc, cong cac, cong co
hai toan » bai toan, hai tan, hach toan
phan van » pham van, thanh van, luan van
tu sach » thu sach, su sach, te sach
hoi tap » hoi dap, hoc tap, hoi tai
hoc tai » hoc dai, hoc tap, hoc bai
cuu mon » cuu mo, cuu mot, cuu cong
mon ban » mong ban, mon bao, con ban
coc ma » hoc ma, co ma, coc ha
ma hai » ta hai, va hai, xa hai

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) or (hoc tai)), nghien cuu mon ban thanh cong coc ma hai toan phan van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((hoi tap) OR (hoc tai)), nghien cuu mon ban thanh cong coc ma hai toan phan van.
• Adding a wildcard symbol may retrieve word variants: tu sach ((hoi tap) or (hoc tai)), nghien cuu mon ban thanh cong coc ma hai toan phan van*.