Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
cac dac » cac dan, cac dai, cac bac
cua tre » cua te, cua triet, dua tren
van vat » van chat, nhan vat
cuu tre » cau tren, cau treo
cac tac » cac toc, cac bac, cac tai
hieu va » lieu va, hieu qua
y nang » ky nang, ly nang, v nang
nang o » nang co, nang ho, nang ro
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: tu sach y nang o hoi. hieu va ((cac tac) OR (cac dac)) va van vat ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang o hoi. hieu va ((cac tac) OR (cac dac)) va van vat ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang o hoi. hieu va ((cac tac) OR (cac dac)) va van vat ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang o hoi. hieu va ((cac tac) OR (cac dac)) va van vat ((cua tre) or (cuu tre))*.