Perhaps you should try some spelling variations:
tan hanh » tan thanh, tang hanh, toan hanh
te sach » toc sach
doi cua » dai cua, hoi cua
cac duc » cac du, cao duc, cac dac
sach lo » sach dao, sach doi, sach hoi
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
ve cac » va cac, vien cac
di cua » dai cua, de cua, do cua

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 lo ((nang cao) or (tang ma)) hoi. hieu ve cac duc tan hanh ((di cua) OR (doi cua)) tuc~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach lo ((nang cao) OR (tang ma)) hoi. hieu ve cac duc tan hanh ((di cua) OR (doi cua)) tuc*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach lo ((nang cao) or (tang ma)) hoi. hieu ve cac duc tan hanh ((di cua) OR (doi cua)) tuc*".