Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
thuoc van » thuoc va, thuc van, thuoc ban
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
va triet » va trien, ve triet, cua triet
co sach » bo sach, cuon sach, hoc sach
sang ma » tang ma, nang ma, sang tao
hanh va » hang va, hanh vi
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach y ((nang cao) or (sang ma)) hoi. hieu van nam thuoc van hanh va ((va triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach y ((nang cao) OR (sang ma)) hoi. hieu van nam thuoc van hanh va ((va triet) OR (va thiet)).
• Adding a wildcard symbol may retrieve word variants: co sach y ((nang cao) or (sang ma)) hoi. hieu van nam thuoc van hanh va ((va triet) or (va thiet))*.