Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
nang xa » lang xa, nang ma, mang xa
xuc van » duc van, luc van, vuc van
sach tu » sach thu, cach tu, sach ty
vi cua » vai cua, di cua
ve cac » va cac
cua su » qua su

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

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