Perhaps you should try some spelling variations:
truc van » truc va, thuc van, truc ban
hanh de » hanh kem
ky dang » ky nang, ky danh
dang ha » dong ha, dung ha, lang ha
hanh va » hang va, hanh vi
hieu va » lieu va, hieu qua
hanh ve » hanh vi, hanh kem
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
va cau » van cau, va cac, va dau
ha hoi » hoa hoi, ha noi, xa hoi
thiet » thieu

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

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