Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » hieu va, thien van, lieu va
thanh do » thanh de, thanh pho, thanh hoa
phan lap » phan dau
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
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 y ((nang xa) OR (nang ma)) hoi. hieu van nam thuc day ((phan lap) or (thanh do)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach y ((nang xa) OR (nang ma)) hoi. hieu van nam thuc day ((phan lap) OR (thanh do)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach y ((nang xa) OR (nang ma)) hoi. hieu van nam thuc day ((phan lap) or (thanh do)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach y ((nang xa) OR (nang ma)) hoi. hieu van nam thuc day ((phan lap) or (thanh do)) cua tre*.