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