Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
minh di » minh ai, minh de, minh duc
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
hac du » cac du, han du, hoc du
hac de » hoc de, tac de, hat de
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: thu sach y nang x ho. hieu van ((hac du) or (hac de)) van minh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang x ho. hieu van ((hac du) OR (hac de)) van minh di cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach y nang x ho. hieu van ((hac du) or (hac de)) van minh di cua tre*.