Perhaps you should try some spelling variations:
van nang » van quang, van ban, van dong
nang dai » nang dau, nang tai, lang dai
cua viet » hoa viet, cua vat, cua dieu
qua cham » qua hai, qua cac, va cham
sach van » sach han, sach va, bach van
hanh vai » hanh vi, hanh va, hanh tai
so sach » so sanh, bo sach, co sach
ca viet » va viet, co viet, hoa viet
thuc va » thuc vat, thuc dan, thuc day
truc va » thuc vat, trung va
dai hoi » dai hoc, dai hai, dai moi

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach van nang dai hoi. hieu qua cham ((truc va) OR (thuc va)) hanh vai ((cua viet) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach van nang dai hoi. hieu qua cham ((truc va) OR (thuc va)) hanh vai ((cua viet) OR (ca viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach van nang dai hoi. hieu qua cham ((truc va) OR (thuc va)) hanh vai ((cua viet) or (ca viet))".
• Adding a wildcard symbol may retrieve word variants: so sach van nang dai hoi. hieu qua cham ((truc va) OR (thuc va)) hanh vai ((cua viet) or (ca viet))*.