Perhaps you should try some spelling variations:
doanh thong » doanh thuong, doanh tong, doanh trong
nghien cua » nghien cuu, nghiep cua, nghiep vua
hoa doanh » toan doanh, hoa dan
thong hoc » thuong hoc, tuong hoc, thong hoa
mach hoc » cach hoc, dich hoc, anh hoc
cong hoa » dong hoa, dong hoc, hang hoa
cac nhan » cac nha, cam nhan, dac nhan
tu mach » tu cach, tu manh, tu hach
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: tu mach hoc tap, nghien cua cong hoa doanh thong hoc ma hoi ((cac nhan) or (ca nhan)) dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu mach hoc tap, nghien cua cong hoa doanh thong hoc ma hoi ((cac nhan) OR (ca nhan)) dan.
• Adding a wildcard symbol may retrieve word variants: tu mach hoc tap, nghien cua cong hoa doanh thong hoc ma hoi ((cac nhan) or (ca nhan)) dan*.