Perhaps you should try some spelling variations:
nuoc sach » nguoi sach, cuoc cach, cuon sach
hoc sach » hoc sinh, hoc cac, hoc anh
thuc van » thuc vat, thuc dan, thuc va
hieu van » hieu va, thien van, lieu va
chuc van » chu van, chuc va, chuc can
hanh di » hanh vi, hanh de, hang di
van cau » van dau, van hau, van chat
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, x ho

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 x hoi. hieu van cau ((chuc van) or (thuc van)) hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((nuoc sach) OR (hoc sach)) ky nang x hoi. hieu van cau ((chuc van) OR (thuc van)) hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((nuoc sach) OR (hoc sach)) ky nang x hoi. hieu van cau ((chuc van) or (thuc van)) hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((nuoc sach) OR (hoc sach)) ky nang x hoi. hieu van cau ((chuc van) or (thuc van)) hanh di cua tre*.