Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
thuc day » thuc dan, thuc vat
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
truc va » thuc va, thuc vat, trung va
ly nang » ky nang, ly hang, ly vang
su sach » so sach, vu sach
v nang » va nang, vu nang, van nang
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 (v nang)) xa hoi. hieu van cham ((truc va) or (thuc day)) hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ly nang) OR (v nang)) xa hoi. hieu van cham ((truc va) OR (thuc day)) hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: su sach ((ly nang) or (v nang)) xa hoi. hieu van cham ((truc va) or (thuc day)) hanh vi cua viet*.