Perhaps you should try some spelling variations:
nghien hieu » nghiep hieu, nghe hieu, thien hieu
doanh khoa » toan khoa
hoc doanh » hoa doanh, hoc danh, hoc dan
mach hoc » cach hoc, dich hoc, anh hoc
hieu mot » thieu mot, hieu moi, hieu so
khoa hoc » hoa hoc
nhan tai » hang tai, van tai, toan tai
tu mach » tu cach, tu manh, tu hach
mot hoc » mon hoc, mo hoc, mot goc
tuan » quan, tran, luan

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 hieu mot hoc doanh khoa hoc ma hoa co ((nhan tai) or (anh tuan))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu mach hoc tap, nghien hieu mot hoc doanh khoa hoc ma hoa co ((nhan tai) OR (anh tuan)).
• Adding a wildcard symbol may retrieve word variants: tu mach hoc tap, nghien hieu mot hoc doanh khoa hoc ma hoa co ((nhan tai) or (anh tuan))*.