Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
su sach » so sach, vu sach
va hanh » van hanh, va danh, ban hanh
cac thu » cach thuc, cac thoi
van cac » van hac, van cau, van bac
ly vang » ly hang, ly van, ly quang
ly nang » ky nang, ly hang, ly quang
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((ly nang) or (ly vang)) x ho. hieu van cac thu ((va hanh) OR (va thanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ly nang) OR (ly vang)) x ho. hieu van cac thu ((va hanh) OR (va thanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ly nang) or (ly vang)) x ho. hieu van cac thu ((va hanh) OR (va thanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((ly nang) or (ly vang)) x ho. hieu van cac thu ((va hanh) OR (va thanh)) vi cua tre*.