Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
thu sach » tu sach, thuat sach, thuoc sach
vien cac » vien bach, vien dai, vien da
nang ro » nang co, nang ra, nang rong
sach ty » sach y, sach tu, sach thu
nang ho » nang hoc, nang co, tang ho
cac thu » cach thuc, cac thoi
cua tre » cua te, cuu tre, cua triet
thu va » thuc va, thue va, tu va
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty ((nang ho) or (nang ro)) hoi. hieu vien cac thu va dan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((nang ho) OR (nang ro)) hoi. hieu vien cac thu va dan vi cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach ty ((nang ho) or (nang ro)) hoi. hieu vien cac thu va dan vi cua tre*.