Perhaps you should try some spelling variations:
hanh doi » thanh doi, hanh noi, hang doi
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
cam thuc » am thuc, nam thuc, cam thu
so sach » bo sach, co sach, hoc sach
doi cua » dai cua, hoi cua
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
mang xa » lang xa, mang may, dang xay
so sanh » do sanh
ve cam » ve cham, ve cac, va cam

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) OR (so sanh)) v ((mang xa) or (nang x)) hoi. hieu ve cam thuc dan hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) v ((mang xa) OR (nang x)) hoi. hieu ve cam thuc dan hanh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) OR (so sanh)) v ((mang xa) or (nang x)) hoi. hieu ve cam thuc dan hanh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((so sach) OR (so sanh)) v ((mang xa) or (nang x)) hoi. hieu ve cam thuc dan hanh doi cua tre*.