Perhaps you should try some spelling variations:
nuoc sach » nguoi sach, hoc sach, cuoc cach
van khang » van khanh, van thanh, van quang
van thang » van thanh, van hang, van than
cau thuc » cau truc, cuu thuc, can thuc
cua tre » cua te, cuu tre, cua triet
hieu ke » hieu kem, chieu ke, hieu ky
kv nang » ky nang, ki nang, ke nang
v nang » va nang, vu nang, van nang
di cua » dai cua, doi cua, de cua
ke cau » ket cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: nuoc sach ((v nang) or (kv nang)) xa hoi. hieu ke cau thuc ((van thang) OR (van khang)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nuoc sach ((v nang) OR (kv nang)) xa hoi. hieu ke cau thuc ((van thang) OR (van khang)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "nuoc sach ((v nang) or (kv nang)) xa hoi. hieu ke cau thuc ((van thang) OR (van khang)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: nuoc sach ((v nang) or (kv nang)) xa hoi. hieu ke cau thuc ((van thang) OR (van khang)) di cua tre*.