Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
va nang » van nang, da nang, cam nang
hieu va » lieu va, hieu qua
hau luc » hau loc, cau luc, nhan luc
luc van » luoc van, luu van, duc van
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
v nang » vu nang, van nang, voi nang
va hau » van hau, va chau, vat hau
de cua » le cua, te cua, dieu 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 ((v nang) or (va nang)) xa hoi. hieu va hau luc van hanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((v nang) OR (va nang)) xa hoi. hieu va hau luc van hanh de cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ((v nang) or (va nang)) xa hoi. hieu va hau luc van hanh de cua tre*.