Perhaps you should try some spelling variations:
hanh doi » thanh doi, hanh noi, hang doi
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
cam thuc » am thuc, nam thuc, cam thu
co sach » cuon 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
bo sach » hoc sach
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: ((co sach) OR (bo sach)) v ((mang xa) or (nang x)) hoi. hieu ve cam thuc van hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((co sach) OR (bo sach)) v ((mang xa) OR (nang x)) hoi. hieu ve cam thuc van hanh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((co sach) OR (bo sach)) v ((mang xa) or (nang x)) hoi. hieu ve cam thuc van hanh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((co sach) OR (bo sach)) v ((mang xa) or (nang x)) hoi. hieu ve cam thuc van hanh doi cua tre*.