Perhaps you should try some spelling variations:
nuoc sach » nguoi sach, cuoc cach, cuon sach
phuc van » phuc va, chuc van, khuc van
hoc sach » hoc sinh, hoc cac, hoc anh
thuc van » thuc vat, thuc dan, thuc va
hanh di » hanh vi, hanh de, hang di
hieu ve » hieu va, hieu van
di cua » dai cua, doi cua, de cua
ve cau » ke cau, va cau, ve cac
nang o » nang co, nang ho, nang ro
cua te » cua tu
o hai » co hai, so hai, o lai

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 hai. hieu ve cau ((phuc van) OR (thuc 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 hai. hieu ve cau ((phuc van) OR (thuc 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 hai. hieu ve cau ((phuc van) OR (thuc van)) hanh di cua te".
• Adding a wildcard symbol may retrieve word variants: ((nuoc sach) or (hoc sach)) ky nang o hai. hieu ve cau ((phuc van) OR (thuc van)) hanh di cua te*.