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
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
vai cua » dai cua, lai cua, bai cua
hai cua » thai cua, dai cua, hoi cua
ve cac » va cac

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 ky nang xa hoi. hieu ((ve cac) OR (vien cac)) vo van hanh ((vai cua) or (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang xa hoi. hieu ((ve cac) OR (vien cac)) vo van hanh ((vai cua) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang xa hoi. hieu ((ve cac) OR (vien cac)) vo van hanh ((vai cua) or (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang xa hoi. hieu ((ve cac) OR (vien cac)) vo van hanh ((vai cua) or (hai cua)) tre*.