Perhaps you should try some spelling variations:
nghien cac » nghiep cach, nghien cuu, nghiep cay
thanh hoa » thanh pho
mach hoc » cach hoc, dich hoc, anh hoc
cac cong » cua cong
co thanh » cho thanh, o thanh, co tranh
toan ban » van ban
su mach » su sach
cong co » dong co, cong cu, cong so
van tai » von tai, van tuan
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su mach hoc tap, nghien cac cong co thanh hoa hoc ma hoi va ((van tai) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su mach hoc tap, nghien cac cong co thanh hoa hoc ma hoi va ((van tai) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: su mach hoc tap, nghien cac cong co thanh hoa hoc ma hoi va ((van tai) or (toan ban))*.