Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
hanh di » hanh vi, hanh de, hang di
sach tu » sach thu, cach tu, sach ty
cua tuc » cua duc, cua tu, cua thuoc
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
ha duc » ha dac, xa duc, hoa duoc
ho duc » hoc duc, do duc, hong duc
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: te sach tu ((nang ma) or (tang ma)) hoi. hieu qua ((ha duc) OR (ho duc)) van hanh di cua tuc~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach tu ((nang ma) OR (tang ma)) hoi. hieu qua ((ha duc) OR (ho duc)) van hanh di cua tuc*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach tu ((nang ma) or (tang ma)) hoi. hieu qua ((ha duc) OR (ho duc)) van hanh di cua tuc*".