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
hoc dai » hoc dan
dai hoi » dai hoc, dai hai, dai moi
hoi dan » hoa dan, hoc dan, hoi dap
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 hoi dan ((nhan va) OR (nhan tai))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te mach hoc tap, nghien cua cong hoc toan khoa hoc dai hoi 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 hoi dan ((nhan va) OR (nhan tai))*.