Perhaps you should try some spelling variations:
hoc doanh » hoa doanh, hoc danh, hoc dan
doanh hoa » doanh khoa, doanh hoan, danh hoa
mach hoc » cach hoc, dich hoc, anh hoc
cuu long » cuu cong, cuu tong, cuu nang
long hoc » dong hoc, long soc, long thuoc
nhan dan » gian dan, nhan tai
phan dau » phan tu, hang dau
su mach » su sach
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 hoc doanh hoa hoc ma hoi va ((nhan dan) OR (phan dau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su mach hoc tap, nghien cuu long hoc doanh hoa hoc ma hoi va ((nhan dan) OR (phan dau))".
• Adding a wildcard symbol may retrieve word variants: su mach hoc tap, nghien cuu long hoc doanh hoa hoc ma hoi va ((nhan dan) OR (phan dau))*.