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, va nang, vu dang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cam luc » cam xuc, cau luc
sach vu » sach va, sach tu, sach uu
hanh de » hanh ve, hanh kem
cua tu » cua tuc, cua su, cua te
cua cu » cua chu, cua cau, cua su

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

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