Perhaps you should try some spelling variations:
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, tu cach
luc van » luoc van, luu van, duc van
cac luc » cau luc, coc luc, cac nuoc
hieu va » lieu va, hieu qua
sang ma » tang ma, sang tao, mang may
te sach » toc sach
nang ma » tang ma, nang cao, mang may
cua tu » cua tuc, cua su, cua cu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (te sach)) y ((nang ma) OR (sang ma)) hoi. hieu va cac luc van hanh dai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) y ((nang ma) OR (sang ma)) hoi. hieu va cac luc van hanh dai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) y ((nang ma) OR (sang ma)) hoi. hieu va cac luc van hanh dai cua tu".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) y ((nang ma) OR (sang ma)) hoi. hieu va cac luc van hanh dai cua tu*.