Perhaps you should try some spelling variations:
phan duc » pham duc, phan tu, phan dau
hieu van » hieu va, thien van, lieu va
phan luc » nhan luc, phan suc, than luc
te sach » toc sach
cua tre » cua te, cuu tre, cua triet
cao hoc » co hoc, cho hoc, chat hoc
y nang » ky nang, ly nang, v nang
anh vi » anh va, anh ve, anh vu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang cao hoc. hieu van ((phan luc) OR (phan duc)) van ((anh vi) or (hanh vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang cao hoc. hieu van ((phan luc) OR (phan duc)) van ((anh vi) OR (hanh vi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang cao hoc. hieu van ((phan luc) OR (phan duc)) van ((anh vi) or (hanh vi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach y nang cao hoc. hieu van ((phan luc) OR (phan duc)) van ((anh vi) or (hanh vi)) cua tre*.