Perhaps you should try some spelling variations:
sach tay » xach tay, sach hay, sach nay
tay tang » tay lang, tay trung, tay quang
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
tang xa » trang xa, tang ma, lang xa
va hang » van hang, va nang, va lang
hang vi » hang va, hanh vi, hang di
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren

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 tay tang xa hoi. hieu van ((pham duc) OR (cam xuc)) va hang vi ((cuu tre) OR (cua tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach tay tang xa hoi. hieu van ((pham duc) or (cam xuc)) va hang vi ((cuu tre) OR (cua tre))~".
• Adding a wildcard symbol may retrieve word variants: su sach tay tang xa hoi. hieu van ((pham duc) or (cam xuc)) va hang vi ((cuu tre) OR (cua tre))*.