Perhaps you should try some spelling variations:
kky nang » ki nang, kha nang, ke nang
te sach » toc sach
vat cua » mat cua, bat cua, dat cua
van vat » van chat, nhan vat
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
tac va » tac da, tuc va, tac ha
tac xa » tuc xa, tac da
o hoc » co hoc, mo hoc, so hoc

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 ((ky nang) or (kky nang)) o hoc. hieu va cac ((tac va) OR (tac xa)) van vat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ky nang) OR (kky nang)) o hoc. hieu va cac ((tac va) OR (tac xa)) van vat cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ky nang) or (kky nang)) o hoc. hieu va cac ((tac va) OR (tac xa)) van vat cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ((ky nang) or (kky nang)) o hoc. hieu va cac ((tac va) OR (tac xa)) van vat cua tre*.