Perhaps you should try some spelling variations:
mach hoc » cach hoc, dich hoc, anh hoc
cuu long » cuu cong, cuu tong, cuu nang
so doanh » so danh, su doanh, hoa doanh
toan hoc » toan khoa, van hoc, tin hoc
gian dan » gian lang
su mach » su sach
long so » long soc, cong so, dong so
va gian » va gianh, van gian, va giai
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: su mach hoc tap, nghien cuu long so doanh ((toan hoc) or (hoa hoc)) ma hoi va gian dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su mach hoc tap, nghien cuu long so doanh ((toan hoc) OR (hoa hoc)) ma hoi va gian dan.
• Adding a wildcard symbol may retrieve word variants: su mach hoc tap, nghien cuu long so doanh ((toan hoc) or (hoa hoc)) ma hoi va gian dan*.