Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
hanh vai » hanh vi, hanh va, hanh tai
vien cam » vien cac, vien cao, vien nam
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
cam luc » cam xuc, cau luc
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
va cai » va cac, va bai, va dai
luc va » duc va, tuc va, loc va
va cay » va cac, va cao, va cau
tu sac » tu sach, tu cac, tu san

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky ((va cay) or (va cai)) phoi. hieu vien cam luc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((va cay) OR (va cai)) phoi. hieu vien cam luc va hanh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((va cay) or (va cai)) phoi. hieu vien cam luc va hanh vai cua tre*.