Perhaps you should try some spelling variations:
nang mai » nang ma, nang tai, lang mai
mai khoi » mai khoa, tai khoa, cac khoi
cua viet » ca viet, hoa viet, cua dieu
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
truc va » thuc va, trung va
hang di » hang doi, hang vi, hang dien
y nang » ky nang, ly nang, v nang

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 khoi. hieu ve cham ((truc va) or (thuc vat)) hang di ((cua viet) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang mai khoi. hieu ve cham ((truc va) OR (thuc vat)) hang di ((cua viet) OR (cua vat)).
• Adding a wildcard symbol may retrieve word variants: su sach y nang mai khoi. hieu ve cham ((truc va) or (thuc vat)) hang di ((cua viet) or (cua vat))*.