Perhaps you should try some spelling variations:
tu tieng » luc tieng, tu tuong, tu trong
thanh ve » hanh ve, thanh va, thanh vien
sach vu » sach va, sach tu, sach uu
duc van » duc va, duc tan, duc manh
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
vu nang » vuc nang, va nang, vu dang
luc van » luoc van, luu van, vuc van
va cau » van cau, va cac, va dau
luc va » duc va, tuc va, loc va
x hoi » xa hoi, o hoi, x ho
ve tu » ve thu, va tu, ve su

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 vu nang x hoi. hieu va cau ((((luc van) OR (luc va))) or (duc van)) thanh ve tu tieng~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang x hoi. hieu va cau ((((luc van) OR (luc va))) OR (duc van)) thanh ve tu tieng.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang x hoi. hieu va cau ((((luc van) OR (luc va))) or (duc van)) thanh ve tu tieng".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang x hoi. hieu va cau ((((luc van) OR (luc va))) or (duc van)) thanh ve tu tieng*.