Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thanh ha » thanh hoa, thanh hai, nhanh ha
va thanh » gia thanh, ban thanh, va tinh
cam thuc » am thuc, nam thuc, cam thu
su sach » so sach, vu sach
cua tre » cua te, cua triet, dua tren
thuc va » thuc vat, thuc dan, thuc day
van cam » van nam, van lam, van cau
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
cuu tre » cau tren, cau treo

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 xa) or (nang ma)) hoi. hieu van cam thuc va thanh ha ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (nang ma)) hoi. hieu van cam thuc va thanh ha ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) or (nang ma)) hoi. hieu van cam thuc va thanh ha ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (nang ma)) hoi. hieu van cam thuc va thanh ha ((cua tre) OR (cuu tre))*.