Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
ban danh » ban doanh, ban hanh, ban dan
han danh » van danh, phan dang, nhan dang
te sach » toc sach
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
sang ma » tang ma, nang ma, sang tao
hieu ve » hieu va, hieu van
ve tham » va tham, ve cham, vi tham
cua tre » cua te, cuu tre, cua triet
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: te sach ky sang ma hoi. hieu ve tham thuc ((ban danh) or (han danh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky sang ma hoi. hieu ve tham thuc ((ban danh) OR (han danh)) dai cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ky sang ma hoi. hieu ve tham thuc ((ban danh) or (han danh)) dai cua tre*.