Perhaps you should try some spelling variations:
nghien cua » nghien cuu, nghiep cua, nghiep vua
mach hoc » cach hoc, dich hoc, anh hoc
cong hoc » dong hoc, cong hoa, cong coc
hoc toan » hoc tan, hop toan, hoa toan
khoa hoc » hoa hoc
nhan tai » hang tai, van tai, toan tai
te mach » ke mach, te sach, tim mach
nhan va » nhan dan, nhan tao, phan van

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te mach hoc tap, nghien cua cong hoc toan khoa hoc dai hoc dan ((nhan va) or (nhan tai))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te mach hoc tap, nghien cua cong hoc toan khoa hoc dai hoc dan ((nhan va) OR (nhan tai)).
• Adding a wildcard symbol may retrieve word variants: te mach hoc tap, nghien cua cong hoc toan khoa hoc dai hoc dan ((nhan va) or (nhan tai))*.