Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hanh vai » hanh vi, hanh va, hanh tai
nang cau » nang cao, hang cau, nang dau
cam tuc » cam xuc, cam tu, nam thuc
cua tre » cua te, cuu tre, dua tren
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach ty, sach kem
hieu va » lieu va, hieu qua
tuc va » thuc va, truc va, tuc xa
va cam » va cham, va cac, va cao

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

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