Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
hai chau » lai chau, ha chau, hat chau
sach thu » sach thue, sach thieu, sach tham
day danh » day manh, dai danh, dao danh
hieu van » hieu va, thien van, lieu va
thuc day » thuc dan, thuc vat
hai chu » hoi chu, hai chi, hai phu
sach ty » sach y, sach tu, xach tay
sang ma » tang ma, nang ma, sang tao
van cam » van nam, van lam, van cau
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: su ((sach ty) OR (sach thu)) sang ma hoi. hieu van cam thuc day danh ((hai chu) or (hai chau)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach thu)) sang ma hoi. hieu van cam thuc day danh ((hai chu) OR (hai chau)) treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach thu)) sang ma hoi. hieu van cam thuc day danh ((hai chu) or (hai chau)) treo".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach thu)) sang ma hoi. hieu van cam thuc day danh ((hai chu) or (hai chau)) treo*.