Perhaps you should try some spelling variations:
nang khoa » hang khoa, dang khoa, nang hoa
khoa hoi » khoan hoi, khoa hoc, khoa doi
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
nam sau » nam sao, nam suu, bam sau
vu sach » vu bach, su sach, vu khach
cac duc » cac du, cao duc, cac dac
co sach » bo sach, cuon sach, hoc sach
van cac » van hac, van cau, van bac
nam su » nam suu, nam so, nam tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sach) or (co sach)) ky nang khoa hoi. hieu van cac duc va hanh ((nam su) OR (nam sau)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (co sach)) ky nang khoa hoi. hieu van cac duc va hanh ((nam su) OR (nam sau)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) or (co sach)) ky nang khoa hoi. hieu van cac duc va hanh ((nam su) OR (nam sau)) triet".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) or (co sach)) ky nang khoa hoi. hieu van cac duc va hanh ((nam su) OR (nam sau)) triet*.