Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
cao nang » cao dang, cam nang, cao tang
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
tham luc » than luc, tham nuoc, tham thuc
vu nang » vuc nang, va nang, vu dang
va hang » van hang, va nang, va lang
hang di » hang doi, hang vi, hang dien
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((vu nang) or (cao nang)) xa hoi. hieu van tham luc va hang di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((vu nang) OR (cao nang)) xa hoi. hieu van tham luc va hang di cua tre.
• Adding a wildcard symbol may retrieve word variants: hoc sach ((vu nang) or (cao nang)) xa hoi. hieu van tham luc va hang di cua tre*.