Perhaps you should try some spelling variations:
nghien huy » nghien cuu, nguyen huy, nghiep quy
doanh khoa » toan khoa
hoc doanh » hoa doanh, hoc danh, hoc dan
mach hoc » cach hoc, dich hoc, anh hoc
khoa hoc » hoa hoc
nhan tai » hang tai, van tai, toan tai
van tuan » van quan, van ban, anh tuan
tu mach » tu cach, tu manh, tu hach
huy mot » huu mot, chua mot, huoc mot
mot hoc » mon hoc, mo hoc, mot goc

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