Perhaps you should try some spelling variations:
dang mai » dang hai, dang mau, dang bai
van hanh » van thanh, ban hanh, van anh
toc sac » toc sach, toc san, hoc sach
cam luc » cam xuc, cau luc
lai cua » dai cua, hai cua, lai chau
bai cua » ban cua, dai cua, bai ca
luc van » luoc van, luu van, duc van
hieu va » lieu va, hieu qua
hieu ve » hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ky dang » ky nang, ky danh
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sac ky dang mai hoi. ((hieu ve) OR (hieu va)) cam luc van hanh ((bai cua) or (lai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky dang mai hoi. ((hieu ve) OR (hieu va)) cam luc van hanh ((bai cua) OR (lai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sac ky dang mai hoi. ((hieu ve) OR (hieu va)) cam luc van hanh ((bai cua) or (lai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sac ky dang mai hoi. ((hieu ve) OR (hieu va)) cam luc van hanh ((bai cua) or (lai cua)) tre*.