Perhaps you should try some spelling variations:
cam truc » cau truc, nam truc, lam truoc
nang tai » hang tai, tang tai, nang cao
hanh lai » hanh lam, hanh tai, thanh lap
sang tai » hang tai, sang tao, tang tai
cua tre » cua te, cuu tre, cua triet
lai cua » dai cua, hai cua, lai chau
hieu ve » hieu van
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
hieu va » lieu va, hieu qua
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky ((nang tai) or (sang tai)) roi. ((hieu ve) OR (hieu va)) cam truc va hanh lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky ((nang tai) OR (sang tai)) roi. ((hieu ve) OR (hieu va)) cam truc va hanh lai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky ((nang tai) or (sang tai)) roi. ((hieu ve) OR (hieu va)) cam truc va hanh lai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sac ky ((nang tai) or (sang tai)) roi. ((hieu ve) OR (hieu va)) cam truc va hanh lai cua tre*.