Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
cam thuc » am thuc, nam thuc, cam thu
thanh va » thanh van, hanh va, thanh ha
thanh ve » hanh ve, thanh vien, thanh van
hieu van » hieu va, thien van, lieu va
thuc va » thuc vat, thuc dan, thuc day
van cam » van nam, van lam, van cau
sach ly » sach y, sach lo, sach ty
hang ma » hang ca, tang ma, nang ma
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: thuoc sach ly ((hang ma) OR (hang va)) hoa. hieu van cam thuc va ((thanh ve) or (thanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ly ((hang ma) OR (hang va)) hoa. hieu van cam thuc va ((thanh ve) OR (thanh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ly ((hang ma) OR (hang va)) hoa. hieu van cam thuc va ((thanh ve) or (thanh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ly ((hang ma) OR (hang va)) hoa. hieu van cam thuc va ((thanh ve) or (thanh va)) cua tre*.