Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
toc sach » hoc sach, doc sach, thuoc sach
hanh lai » hanh lam, hanh tai, thanh lap
van hanh » van thanh, ban hanh, van anh
vien cac » vien bach, vien dai, vien da
lai cua » dai cua, hai cua, lai chau
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
cua tre » cua te, cuu tre, cua triet
cac vo » cac co, cac vi, cac bo

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ky ((nang xa) or (lang xa)) hoi. hieu vien cac vo van hanh lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky ((nang xa) OR (lang xa)) hoi. hieu vien cac vo van hanh lai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky ((nang xa) or (lang xa)) hoi. hieu vien cac vo van hanh lai cua tre*.