Perhaps you should try some spelling variations:
thanh dat » thanh hai, thanh van, thanh ha
nang noi » nang doc
noi khoa » ngoai khoa, hoc khoa, tai khoa
cac tuc » cac toc, cac tu, cac tac
hieu ve » hieu va, hieu van
sach ty » sach y, sach thu, xach tay
sach tu » sach thu, cach tu, sach uu
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach ty) or (sach tu)) nang noi khoa. hieu ve cac tuc va ((thanh dat) or (thanh san)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach ty) OR (sach tu)) nang noi khoa. hieu ve cac tuc va ((thanh dat) OR (thanh san)) cua tre.
• Adding a wildcard symbol may retrieve word variants: so ((sach ty) or (sach tu)) nang noi khoa. hieu ve cac tuc va ((thanh dat) or (thanh san)) cua tre*.