Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
hieu van » hieu va, thien van, lieu va
va dinh » van dinh, va kinh, va tinh
thuc va » thuc vat, thuc dan, thuc day
van cau » van dau, van hau, van chat
sac ky » cac ky, sai ky
di cuu » di cua, dinh cuu
di cau » da cau, diem cau
vu sac » vu sach, vu san, va sac
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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

• If you are trying to use Boolean operators, they must be ALL CAPS: vu sac ky nang ((x hoi) OR (o hoi)). hieu van cau thuc va dinh ((di cuu) OR (di cau)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sac ky nang ((x hoi) OR (o hoi)). hieu van cau thuc va dinh ((di cuu) or (di cau)) tre~".
• Adding a wildcard symbol may retrieve word variants: vu sac ky nang ((x hoi) OR (o hoi)). hieu van cau thuc va dinh ((di cuu) or (di cau)) tre*.