Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
va trinh » van trinh, va tinh, lap trinh
doi cua » dai cua, hoi cua
doc cua » hoc cua, do cua, goc cua
cac duc » cac du, cao duc, cac dac
su sach » so sach, vu sach
kv nang » ky nang, ki nang, ke nang
v nang » va nang, vu nang, van nang

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 (kv nang)) xa hoi. hieu vien cac duc va trinh ((doc cua) OR (doi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (kv nang)) xa hoi. hieu vien cac duc va trinh ((doc cua) OR (doi cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) or (kv nang)) xa hoi. hieu vien cac duc va trinh ((doc cua) OR (doi cua)) tre*".