Perhaps you should try some spelling variations:
sach thien » sach thieu, sach tien, cach thien
thien nang » thien bang, thien dang, trien nang
thien van » thi van
hieu van » hieu va, lieu va, hieu ve
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, nam thuc
nang xa » nang x, lang xa, nang ma
ca tren » cau tren, cu tren, la tren
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach thien nang xa hoi. ((hieu van) OR (thien van)) cam tuc va hanh va ((cua tre) or (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thien nang xa hoi. ((hieu van) OR (thien van)) cam tuc va hanh va ((cua tre) OR (ca tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thien nang xa hoi. ((hieu van) OR (thien van)) cam tuc va hanh va ((cua tre) or (ca tren))".
• Adding a wildcard symbol may retrieve word variants: su sach thien nang xa hoi. ((hieu van) OR (thien van)) cam tuc va hanh va ((cua tre) or (ca tren))*.