Perhaps you should try some spelling variations:
thuat mach » thuat sach, thuat tach, thuyet mach
van thanh » van tuan
ban thanh » ban hanh, ban hang
mach hoc » cach hoc, dich hoc, anh hoc
bia khoa » da khoa
huu hoa » huu ho, huu hoi, uu hoa
hoc bia » hoc gia, hoc giao, hoc giai
hoc xa » hoc ma

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat mach hoc tap, nhiem huu hoa hoc bia khoa hoc xa hoi ((van thanh) or (ban thanh)) van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat mach hoc tap, nhiem huu hoa hoc bia khoa hoc xa hoi ((van thanh) OR (ban thanh)) van.
• Adding a wildcard symbol may retrieve word variants: thuat mach hoc tap, nhiem huu hoa hoc bia khoa hoc xa hoi ((van thanh) or (ban thanh)) van*.