Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
cam thuc » am thuc, nam thuc, cam thu
thanh va » thanh van, hanh va, thanh ha
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
va cua » va chua, via cua, ca cua

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 ky ((nang ma) or (tang ma)) hoi. hieu ve cam thuc vat thanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang ma) OR (tang ma)) hoi. hieu ve cam thuc vat thanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang ma) or (tang ma)) hoi. hieu ve cam thuc vat thanh va cua tre*.