Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
thanh vi » hanh vi, thanh va, thanh ve
sach ky » sach y, sach ty, sach kem
mai hoi » mai khoi, dai hoi, lai hoi
van cau » van dau, van hau, van chat
cau dat » cai dat, cau hat, chap dat
sac ky » cac ky, sai ky
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ky) or (sac ky)) sang mai hoi. hieu van cau dat va thanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sac ky)) sang mai hoi. hieu van cau dat va thanh vi cua vat.
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sac ky)) sang mai hoi. hieu van cau dat va thanh vi cua vat*.