Perhaps you should try some spelling variations:
thuyet tach » thuyet mach, thuyet hach, thuyet xac
hoc thuyet » hoc chuyen
khong cong » thong cong, khong cang, chong cong
tinh cua » trinh cua, tinh chat, tranh cua
sinh cua » manh cua, dinh cuu, sinh va
cong san » cong tac
than ban » thanh ban, than man, nhuan ban
toan ban » van ban

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thuyet tach - hanh ((tinh cua) OR (sinh cua)) khong cong san ((than ban) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thuyet tach - hanh ((tinh cua) OR (sinh cua)) khong cong san ((than ban) or (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: hoc thuyet tach - hanh ((tinh cua) OR (sinh cua)) khong cong san ((than ban) or (toan ban))*.