Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang noi » nang doc
hieu van » hieu va, thien van, lieu va
thuc van » thuc vat, thuc dan, thuc va
so triet » su triet, so thiet, bo triet
van anh » van thanh, tuan anh, van minh
anh dai » vanh dai, anh bai, anh dat
nang o » nang co, nang ho, nang ro
van am » van nam, van lam, van dam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ky ((nang o) or (nang noi)) hoc. hieu van am thuc van anh dai so triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky ((nang o) OR (nang noi)) hoc. hieu van am thuc van anh dai so triet.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky ((nang o) or (nang noi)) hoc. hieu van am thuc van anh dai so triet*.