Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
va triet » va thiet, va trien, ve triet
nang doc » nang luc
vien cac » vien bach, vien dai, vien da
ky dang » ky nang, ky danh
cac tuc » cac toc, cac tu, cac tac
ky lang » ky nang, ky tang, tay lang
tu sach » thu sach, su sach, te sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ky lang) OR (ky dang)) xa hoi. hieu vien cac tuc xa ((nang noi) or (nang doc)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky dang)) xa hoi. hieu vien cac tuc xa ((nang noi) OR (nang doc)) va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) OR (ky dang)) xa hoi. hieu vien cac tuc xa ((nang noi) or (nang doc)) va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) OR (ky dang)) xa hoi. hieu vien cac tuc xa ((nang noi) or (nang doc)) va triet*.