Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
va trien » va truyen, va thiet, va tuyen
van hanh » van thanh, ban hanh, van ban
vien cac » vien bach, vien dai, vien da
cac toi » cac thoi
ty nang » ky nang, ty hang, ly nang
van anh » van thanh, tuan anh, van minh
su sach » so sach, vu sach
vi va » vi van, vai va, vu 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 ((ty nang) OR (ty xang)) xa hoi. hieu vien cac toi ((van hanh) or (van anh)) vi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty nang) OR (ty xang)) xa hoi. hieu vien cac toi ((van hanh) OR (van anh)) vi va trien*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) OR (ty xang)) xa hoi. hieu vien cac toi ((van hanh) or (van anh)) vi va trien*".