Perhaps you should try some spelling variations:
dam thuc » am thuc, dan thuc, dai thuc
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
te sach » toc sach
tai cuu » tai cuc, tai buu, tai cua
cuu tre » cua tre, cau tren, cau treo
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ty ((nang ma) or (nang x)) hoi. hieu ve ((dam thuc) or (nam thuc)) van hanh tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty ((nang ma) OR (nang x)) hoi. hieu ve ((dam thuc) OR (nam thuc)) van hanh tai cuu tre.
• Adding a wildcard symbol may retrieve word variants: te sach ty ((nang ma) or (nang x)) hoi. hieu ve ((dam thuc) or (nam thuc)) van hanh tai cuu tre*.