Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cam thuc » nam thuc, cam thu, can thuc
da thanh » dao thanh, dat thanh, dam thanh
thanh va » thanh van, hanh va, thanh ha
sach ty » sach tu, sach thu, xach tay
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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 y)) nang xa hoi. hieu van ((cam thuc) or (am thuc)) da thanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach ty) OR (sach y)) nang xa hoi. hieu van ((cam thuc) OR (am thuc)) da thanh va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach ty) OR (sach y)) nang xa hoi. hieu van ((cam thuc) or (am thuc)) da thanh va cua tre*".