Perhaps you should try some spelling variations:
doanh khoa » toan khoa
hoc doanh » hoa doanh, hoc danh, hoc dan
sach hoc » cach hoc, sach hoi, mach hoc
khoa hoc » hoa hoc
nhan dan » gian dan, nhan tai
phan dau » phan tu, hang dau
tu sach » thu sach, su sach, te sach
mo hoc » mon 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: tu sach hoc tap, nghien cuu mo hoc doanh khoa hoc xa hoi va ((nhan dan) OR (phan dau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach hoc tap, nghien cuu mo hoc doanh khoa hoc xa hoi va ((nhan dan) OR (phan dau))".
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien cuu mo hoc doanh khoa hoc xa hoi va ((nhan dan) OR (phan dau))*.