Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh doi » thanh doi, hanh noi, hang doi
te sach » toc sach
sach ty » sach y, sach tu, sach thu
cho hoc » khoa hoc
hieu ve » hieu va, hieu van
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
doi cua » dai cua, hoi cua
cua cau » cua cac, cua chu, cua cay
ve cac » va cac, vien 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 xang ((cho hoc) or (co hoc)). hieu ve cac luc van hanh doi cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty xang ((cho hoc) OR (co hoc)). hieu ve cac luc van hanh doi cua cau*.