Perhaps you should try some spelling variations:
cuon sach » duong sach, cuoc cach, co sach
hoc sach » hoc sinh, hoc cac, hoc anh
van hanh » van thanh, ban hanh, van anh
phuc van » thuc van, phuc va, chuc van
hanh di » hanh vi, hanh de, hang di
ke cau » ket cau
di cua » dai cua, doi cua, de cua
ve cau » va cau, ve cac, le cau
nang o » nang co, nang ho, nang ro
cua te » cua tu
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: ((cuon sach) or (hoc sach)) ky nang o hoi. hieu ((ve cau) OR (ke cau)) phuc van hanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((cuon sach) OR (hoc sach)) ky nang o hoi. hieu ((ve cau) OR (ke cau)) phuc van hanh di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((cuon sach) or (hoc sach)) ky nang o hoi. hieu ((ve cau) OR (ke cau)) phuc van hanh di cua te".
• Adding a wildcard symbol may retrieve word variants: ((cuon sach) or (hoc sach)) ky nang o hoi. hieu ((ve cau) OR (ke cau)) phuc van hanh di cua te*.