Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thuc day » thuc dan, thuc vat
hanh vai » hanh vi, hanh tai, hanh van
hieu van » hieu va, thien van, lieu va
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan
van cam » van nam, van lam, van cau
danh ma » anh ma, danh ca, hanh ma
ky danh » ky anh, ky dang

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky danh ma hoa. hieu van cam ((thuc va) or (thuc day)) ((hanh vai) OR (hanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky danh ma hoa. hieu van cam ((thuc va) OR (thuc day)) ((hanh vai) OR (hanh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky danh ma hoa. hieu van cam ((thuc va) or (thuc day)) ((hanh vai) OR (hanh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky danh ma hoa. hieu van cam ((thuc va) or (thuc day)) ((hanh vai) OR (hanh va)) cua tre*.