Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
nang mai » nang ma, nang tai, lang mai
hieu van » hieu va, thien van, lieu va
hang di » hang doi, hang vi, hang dien
thuc va » thuc vat, thuc dan, thuc day
truc va » thuc vat, trung va
su sach » so sach, vu sach
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va
y nang » ky nang, ly nang, v nang
di cua » dai cua, doi cua, de 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 y nang mai hoi. ((hieu ve) or (hieu van)) cam ((truc va) or (thuc va)) hang di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang mai hoi. ((hieu ve) OR (hieu van)) cam ((truc va) OR (thuc va)) hang di cua viet.
• Adding a wildcard symbol may retrieve word variants: su sach y nang mai hoi. ((hieu ve) or (hieu van)) cam ((truc va) or (thuc va)) hang di cua viet*.