Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
thanh di » thanh doi, thanh de, thanh do
su sach » so sach, vu 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 van
hieu va » lieu va, hieu qua
cau loc » hau loc, cau hoc, cau luc
loc va » hoc va, luc va
di cua » dai cua, doi cua, de 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 sang ma hoa. ((hieu ve) or (hieu va)) cau loc va thanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang ma hoa. ((hieu ve) OR (hieu va)) cau loc va thanh di cua vat.
• Adding a wildcard symbol may retrieve word variants: su sach ky sang ma hoa. ((hieu ve) or (hieu va)) cau loc va thanh di cua vat*.