Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
ky lang » ky nang, ky dang, ky tang
lang ha » long ha
hieu va » lieu va, hieu qua
va toan » van toan, bai toan, tap toan
toan le » tuan le, toan ly, toan ke
va hanh » va thanh, va danh, ban hanh
luu tre » luu tru, cuu tre, luy tre
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
ha hoi » hoa hoi, ha noi, xa hoi
vi luu » vi lua

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 lang ha hoi. hieu va toan le ((va hanh) or (van hanh)) vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky lang ha hoi. hieu va toan le ((va hanh) OR (van hanh)) vi luu tre.
• Adding a wildcard symbol may retrieve word variants: te sac ky lang ha hoi. hieu va toan le ((va hanh) or (van hanh)) vi luu tre*.