Perhaps you should try some spelling variations:
sach thien » sach thieu, sach tien, cach thien
thien nang » thien bang, thien dang, trien nang
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
hanh va » hanh vi
tu sach » thu sach, su sach, te sach
cam tuc » cam xuc, cam tu, nam thuc
van cam » van nam, van lam, van cau
nang xa » nang x, lang xa, nang ma
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: tu sach thien nang xa hoi. hieu van cam tuc va ((hanh va) OR (hang va)) ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thien nang xa hoi. hieu van cam tuc va ((hanh va) OR (hang va)) ((cua tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thien nang xa hoi. hieu van cam tuc va ((hanh va) OR (hang va)) ((cua tre) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach thien nang xa hoi. hieu van cam tuc va ((hanh va) OR (hang va)) ((cua tre) or (cau tren))*.