Perhaps you should try some spelling variations:
hoi doanh » hoa doanh, voi doanh, doi doanh
sach doi » sach hoi, sach moi, sach dao
khoa hoc » hoa hoc
nhan dan » phan dau, gian dan, nhan tai
vu sach » vu bach, su sach, vu khach
doi tap » doi tac, doi dap, doi tai
mon hoc » toan hoc, dong hoc
mo hoc » co hoc
hoc xa » hoc ma

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach doi tap, nghien cuu ((mo hoc) or (mon hoc)) toan khoa hoc xa hoi doanh nhan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach doi tap, nghien cuu ((mo hoc) OR (mon hoc)) toan khoa hoc xa hoi doanh nhan dan.
• Adding a wildcard symbol may retrieve word variants: vu sach doi tap, nghien cuu ((mo hoc) or (mon hoc)) toan khoa hoc xa hoi doanh nhan dan*.