Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi nang » thi cong, ki nang, thi hanh
su sach » so sach, vu sach
cam tuc » cam xuc, nam thuc, dam thuc
va hanh » van hanh, va thanh, va danh
cam tu » cam thu, nam tu, dam tu
x hoi » xa hoi, o hoi, x ho

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: su sach thi nang x hoi. hieu qua ((cam tuc) OR (cam tu)) va hanh ((vi luu) OR (vi lua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thi nang x hoi. hieu qua ((cam tuc) OR (cam tu)) va hanh ((vi luu) or (vi lua)) tre~".
• Adding a wildcard symbol may retrieve word variants: su sach thi nang x hoi. hieu qua ((cam tuc) OR (cam tu)) va hanh ((vi luu) or (vi lua)) tre*.