Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
duc van » duc va, duc manh, duc phan
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
anh de » anh d, anh ve, anh du
x hoi » xa hoi, o hoi, x ho

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 hoi. hieu van tham ((duc van) or (duc tan)) ((anh de) or (hanh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang x hoi. hieu van tham ((duc van) OR (duc tan)) ((anh de) OR (hanh de)) cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach y nang x hoi. hieu van tham ((duc van) or (duc tan)) ((anh de) or (hanh de)) cua tre*.