Perhaps you should try some spelling variations:
tu tieng » luc tieng, tu tuong, tu trong
dua tren » dung tren
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
dau truc » cau truc, dai truc, doan truc
tu sach » thu sach, su sach, tu cach
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
te sach » toc sach
y nang » ky nang, ly nang, v nang
va dau » va dao

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) y nang xa hoi. hieu va dau truc van hanh vi ((dua tren) OR (tu tieng))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (te sach)) y nang xa hoi. hieu va dau truc van hanh vi ((dua tren) or (tu tieng))~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (te sach)) y nang xa hoi. hieu va dau truc van hanh vi ((dua tren) or (tu tieng))*.