Perhaps you should try some spelling variations:
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
te sach » toc sach
hac duc » hoc duc, ha duc, thach duc
sach ty » sach y, sach tu, sach thu
hieu va » lieu va, hieu qua
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
cua tuc » cua duc, cua tu, cua thuoc
va hac » van hac, va khac, va cac

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 ty ((sang ma) OR (nang ma)) hoi. hieu va hac duc ((van hanh) or (ban hanh)) dai cua tuc~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty ((sang ma) OR (nang ma)) hoi. hieu va hac duc ((van hanh) OR (ban hanh)) dai cua tuc*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty ((sang ma) OR (nang ma)) hoi. hieu va hac duc ((van hanh) or (ban hanh)) dai cua tuc*".