Perhaps you should try some spelling variations:
tu tieng » luc tieng, tu tuong, tu trong
dau truc » cau truc, dai truc, doan truc
dua tren » dung tren
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
tu sach » su sach, te sach, tu cach
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
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 (thu sach)) ky 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 (thu sach)) ky 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 (thu sach)) ky nang xa hoi. hieu va dau truc van hanh vi ((dua tren) or (tu tieng))*.