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

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 vi ((cua tre) OR (cua te))~.
• 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 vi ((cua tre) OR (cua te)).
• 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 vi ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: toc sach ky danh ma hoa. hieu van cam ((thuc va) or (thuc day)) hanh vi ((cua tre) OR (cua te))*.