Perhaps you should try some spelling variations:
van phan » van phong, van thanh, luan phan
phan duc » pham duc, phan tu, phan dau
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
lai cua » dai cua, hai cua, lai chau
va danh » va dinh, va dan, va hanh
cao hoi » cau hoi, co hoi, cao hoc
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ty nang cao hoi. hieu van phan duc ((va thanh) or (va danh)) lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ty nang cao hoi. hieu van phan duc ((va thanh) OR (va danh)) lai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ty nang cao hoi. hieu van phan duc ((va thanh) or (va danh)) lai cua tre*.