Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
thuc day » thuc dan, thuc vat
day hanh » day nhanh, day thanh, dao hanh
su sach » so sach
vu sach » vu bach, vu khach
ly nang » ly hang, ly vang, 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) OR (vu sach)) ((ly nang) or (ky nang)) x ho. hieu van cham thuc day hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) ((ly nang) OR (ky nang)) x ho. hieu van cham thuc day hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (vu sach)) ((ly nang) or (ky nang)) x ho. hieu van cham thuc day hanh vi cua tre*".