Perhaps you should try some spelling variations:
sach hoi » sach doi, sach moi, cach thoi
cau thuc » cau truc, cuu thuc, can thuc
vat hanh » vat thanh, van hanh, va hanh
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
sach o » sach lo, sac o, sach y
va cau » van cau, va cac, va dau
ve cua » le cua, de cua, ve cum
te cua » tue cua, le 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: thu ((sach o) or (sach hoi)) lang xa hoi. hieu va cau thuc vat hanh ((ve cua) or (te cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach o) OR (sach hoi)) lang xa hoi. hieu va cau thuc vat hanh ((ve cua) OR (te cua)) te.
• Adding a wildcard symbol may retrieve word variants: thu ((sach o) or (sach hoi)) lang xa hoi. hieu va cau thuc vat hanh ((ve cua) or (te cua)) te*.