Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
vu nang » vuc nang, va nang, vu dang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cao xuc » cam xuc, cao duc, chat xuc
sach vu » sach va, sach tu, sach uu
hanh ve » hanh vi, hanh va, hanh kem
cao suc » cao su, cao duc
ve su » va su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach vu nang xa hoi. hieu va ((cao xuc) or (cao suc)) van hanh ve su (kien OR tien)~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang xa hoi. hieu va ((cao xuc) OR (cao suc)) van hanh ve su (kien OR tien).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang xa hoi. hieu va ((cao xuc) or (cao suc)) van hanh ve su (kien OR tien)".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang xa hoi. hieu va ((cao xuc) or (cao suc)) van hanh ve su (kien OR tien)*.