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 » phan dau, gian dan, nhan tai
su mach » su sach
mai hoi » mai khoi, dai hoi, lai hoi
va nhan » van nhan, ca nhan, va phan

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 hoa) or (mai hoi)) va nhan dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su mach hoc tap, nghien cuu long hoc doanh hoa hoc ((ma hoa) OR (mai hoi)) va nhan dan.
• Adding a wildcard symbol may retrieve word variants: su mach hoc tap, nghien cuu long hoc doanh hoa hoc ((ma hoa) or (mai hoi)) va nhan dan*.