Perhaps you should try some spelling variations:
vanh dai » van dai, vanh tai, lanh dao
te sach » toc sach
sach ty » sach y, sach tu, sach thu
dai cuu » dai cua, dai huu
va vanh » va van, va danh, va hanh
cac tac » cac toc, cac bac, cac dac
cuu tre » cua tre, cau tren, cau treo
cac tuc » cac toc, cac nuoc, cac cuoc
hieu va » lieu va, hieu qua
ty nang » ky nang, ty xang, ty hang
cac tu » cac thu, cach tu, cac du
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: te sach ty nang o hoi. hieu va ((((cac tuc) OR (cac tac))) or (cac tu)) va vanh dai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang o hoi. hieu va ((((cac tuc) OR (cac tac))) OR (cac tu)) va vanh dai cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang o hoi. hieu va ((((cac tuc) OR (cac tac))) or (cac tu)) va vanh dai cuu tre*".