Perhaps you should try some spelling variations:
danh viet » anh viet, ninh viet, nang viet
doc sach » hoc sach, toc sach, nuoc sach
thuc day » thuc dan
viet cua » viec cua, viet ca, viet qua
tang ma » mang may, tang van
va tham » van tham, va cham, va thanh
cua tre » cua te, cuu tre, cua triet
y tang » ky tang, 6 tang, 7 tang
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach y tang ma hoi. lieu va tham ((thuc vat) or (thuc day)) danh viet cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach y tang ma hoi. lieu va tham ((thuc vat) OR (thuc day)) danh viet cua tre.
• Adding a wildcard symbol may retrieve word variants: doc sach y tang ma hoi. lieu va tham ((thuc vat) or (thuc day)) danh viet cua tre*.