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
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
cac lop » cac hop, cac loai
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
lop va » lap va, hop va, nop va
va cua » va chua, via cua, ca 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 ky ((nang xa) or (nang x)) hoi. hieu vien cac lop va hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang xa) OR (nang x)) hoi. hieu vien cac lop va hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang xa) or (nang x)) hoi. hieu vien cac lop va hanh va cua tre*.