Perhaps you should try some spelling variations:
nghien huu » nghien cuu, nguyen huu, nhiem huu
ngan nang » ngan hang, ngan bang, nganh nong
mach hoc » cach hoc, dich hoc, anh hoc
sach hoi » sach doi, sach moi, cach thoi
hoa ngan » hoa ngon, hoa nhan, toan ngan
nang hoc » nang doc, nang luc, dong hoc
cac phan » cac nhan, cao phan, cap phan
phan van » pham van, thanh van, luan van
son hoa » so hoa, mon hoa, son ha
hoi cac » hoc cac, voi cac, hoa cac
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 ((mach hoc) or (sach hoi)) tap, nghien huu son hoa ngan nang hoc xa hoi cac phan van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((mach hoc) OR (sach hoi)) tap, nghien huu son hoa ngan nang hoc xa hoi cac phan van.
• Adding a wildcard symbol may retrieve word variants: tu ((mach hoc) or (sach hoi)) tap, nghien huu son hoa ngan nang hoc xa hoi cac phan van*.