Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
thi cua » thai cua, thi cuc, tri cua
dan thi » dang thi, tran thi, dinh thi
cac tac » cac toc, cac bac, cac dac
cac tuc » cac toc, cac tu, cac nuoc
va nang » van nang, da nang, cam nang
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau
v nang » vu nang, van nang, voi nang

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 ((v nang) or (va nang)) xa hoi. hieu qua ((cac tuc) or (cac tac)) va dan thi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((v nang) OR (va nang)) xa hoi. hieu qua ((cac tuc) OR (cac tac)) va dan thi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ((v nang) or (va nang)) xa hoi. hieu qua ((cac tuc) or (cac tac)) va dan thi cua tre*.