Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
hanh doi » thanh doi, hanh noi, hang doi
su sach » so sach, vu sach
nang xa » lang xa, nang ma, mang xa
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet

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 y ((nang xa) or (nang x)) hoi. hieu ve cham thuc van hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (nang x)) hoi. hieu ve cham thuc van hanh doi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (nang x)) hoi. hieu ve cham thuc van hanh doi cua tre*.