Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cac thuc » cach thuc, cac thu, can thuc
danh vai » danh sai, danh va, doanh van
so sach » so sanh, bo sach, co sach
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
van cac » van hac, van cau, van bac
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet

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 y ((nang xa) or (nang ma)) hoi. hieu van cac thuc va danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((nang xa) OR (nang ma)) hoi. hieu van cac thuc va danh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach y ((nang xa) or (nang ma)) hoi. hieu van cac thuc va danh vai cua tre*.