Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va hanh » van hanh, va thanh, va danh
vu nang » vuc nang, vu dang, v nang
hanh de » hanh ve, hanh kem
va nang » van nang, da nang, cam nang
hieu va » lieu va, hieu qua
cau luc » cau truc, cau phuc
de cua » le cua, te cua, dieu cua
cua te » cua tu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((vu nang) OR (va nang)) xa hoi. hieu va ((cau luc) OR (chau au)) va hanh de cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((vu nang) OR (va nang)) xa hoi. hieu va ((cau luc) or (chau au)) va hanh de cua te~".
• Adding a wildcard symbol may retrieve word variants: toc sach ((vu nang) OR (va nang)) xa hoi. hieu va ((cau luc) or (chau au)) va hanh de cua te*.