Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cam thuc » nam thuc, cam thu, can thuc
day hanh » day nhanh, day thanh, dao hanh
su sach » so sach
vu sach » vu bach, vu khach
ly nang » ky nang, ly hang, ly vang
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 x ho. hieu van ((cam thuc) or (am 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 x ho. hieu van ((cam thuc) OR (am thuc)) day hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) ly nang x ho. hieu van ((cam thuc) or (am thuc)) day hanh vi cua tre*.