Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
van khang » van khanh, van thanh, van quang
vien cac » vien bach, vien dai, vien da
cac truc » cau truc, cac tru, cac trung
su sach » so sach, vu sach
su tien » su kien, su hien, tu tieng
va nang » van nang, da nang, cam nang
v nang » vu nang, van nang, voi nang
x hoi » xa hoi, o hoi, x ho
di su » doi su, ki su, da su

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 ((v nang) OR (va nang)) x hoi. hieu vien cac truc ((van khang) or (tran quang)) di su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (va nang)) x hoi. hieu vien cac truc ((van khang) OR (tran quang)) di su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) OR (va nang)) x hoi. hieu vien cac truc ((van khang) or (tran quang)) di su tien".
• Adding a wildcard symbol may retrieve word variants: su sach ((v nang) OR (va nang)) x hoi. hieu vien cac truc ((van khang) or (tran quang)) di su tien*.