Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
viec cac » vien cac, viec cua, viec lam
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
va thanh » gia thanh, ban thanh, va tinh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
doi cua » dai cua, hoi cua, dong cua
vi cua » vai cua, di cua
x hoi » o hoi, x ho, 5 hoi

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 ty nang ((x hoi) OR (xa hoi)). hieu viec cac nuoc va thanh ((vi cua) or (doi cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((x hoi) OR (xa hoi)). hieu viec cac nuoc va thanh ((vi cua) OR (doi cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((x hoi) OR (xa hoi)). hieu viec cac nuoc va thanh ((vi cua) or (doi cua)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((x hoi) OR (xa hoi)). hieu viec cac nuoc va thanh ((vi cua) or (doi cua)) triet*.