Perhaps you should try some spelling variations:
hien hanh » dieu hanh
hien bach » vien bach, thien hach, dien sach
va triet » va thiet, ve triet, cua triet
va trien » va truyen, va thiet, va tuyen
sach ky » sac ky, sach y, sach ty
tuoc va » thuoc va, nuoc va, duoc va
su sach » so sach, vu sach
va dan » ca dan, va dao, va dau
dan du » dan dau, danh du, dan su
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang o hoi. hieu ((hien bach) or (hien hanh)) tuoc va dan du ((va triet) OR (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang o hoi. hieu ((hien bach) OR (hien hanh)) tuoc va dan du ((va triet) OR (va trien))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang o hoi. hieu ((hien bach) or (hien hanh)) tuoc va dan du ((va triet) OR (va trien))*".