Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
han danh » van danh, phan dang, nhan dang
ban danh » ban doanh, ban hanh, ban dan
ve tham » va tham, ve cham, vi tham
hieu ve » hieu va, hieu van
sach ky » sach y, sach ty, sach kem
sang ma » tang ma, nang ma, sang tao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky

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) OR (sac 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) OR (sac ky)) sang ma hoi. hieu ve tham thuc ((ban danh) OR (han danh)) dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) OR (sac 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) OR (sac ky)) sang ma hoi. hieu ve tham thuc ((ban danh) or (han danh)) dai cua tre*.