Perhaps you should try some spelling variations:
sach thien » sach thieu, sach tien, cach thien
thien nang » thien bang, thien dang, trien nang
dua tren » dung tren
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
van cau » van dau, van hau, van chat
van cam » van nam, van lam, van dam
nang xa » nang x, lang xa, nang ma
cuu tre » cua tre, cau tren, cau treo
xuc va » duc va, tuc va, luc va

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) or (van cau)) xuc va hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thien nang xa hoi. hieu ((van cam) OR (van cau)) xuc va hanh vi ((dua tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach thien nang xa hoi. hieu ((van cam) or (van cau)) xuc va hanh vi ((dua tren) or (cuu tre))*.