Perhaps you should try some spelling variations:
sach thien » sach thieu, cach thien, sach tren
sach tien » sach tren, sach thieu
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, nam thuc
van cam » van nam, van lam, van cau
ca tren » cau tren, cu tren, la tren
tuc va » thuc va, truc va, tuc xa
x hoi » xa hoi, o hoi, x ho

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