Perhaps you should try some spelling variations:
tu sang » thu sang, tu san, tu lang
vai cua » dai cua, hai cua, lai cua
dan vai » dan va, dan tai, dan vat
cac xuc » cam xuc, cac nuoc, chat xuc
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau
ke va » te va
ky va » ly va, my va, ky la
nuoc » quoc, duoc, ngoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sang ((ky va) OR (ke va)) xa hoi. hieu ve ((cac xuc) or (hoc nuoc)) va dan vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sang ((ky va) OR (ke va)) xa hoi. hieu ve ((cac xuc) OR (hoc nuoc)) va dan vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sang ((ky va) OR (ke va)) xa hoi. hieu ve ((cac xuc) or (hoc nuoc)) va dan vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sang ((ky va) OR (ke va)) xa hoi. hieu ve ((cac xuc) or (hoc nuoc)) va dan vai cua tre*.