Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
van hanh » van thanh, ban hanh, van anh
tuc van » thuc van, truc van, tuc va
su sach » so sach, vu sach
ky dang » ky danh
cac tuc » cac toc, cac tu, cac tac
vai va » mai va, hai va, lai va
dai va » mai va

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

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