Perhaps you should try some spelling variations:
hieu luc » hieu luat, hieu qua
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
nhan luc » nang luc
te sach » toc sach
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
hau luc » hau loc, cau luc, than luc
nang xa » nang x, lang xa, nang ma
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
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 xa hoi. hieu van ((((hau luc) OR (hieu luc))) or (nhan luc)) van hanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach v nang xa hoi. hieu van ((((hau luc) OR (hieu luc))) OR (nhan luc)) van hanh de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach v nang xa hoi. hieu van ((((hau luc) OR (hieu luc))) or (nhan luc)) van hanh de cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach v nang xa hoi. hieu van ((((hau luc) OR (hieu luc))) or (nhan luc)) van hanh de cua tre*.