Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
hieu ve » hieu va, hieu van
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
cuu tre » cau tren, cau treo
ve cam » ve cham, ve cac, va cam
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: ((te sach) OR (toc sach)) ky tang xa hoi. hieu ve cam xuc va hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky tang xa hoi. hieu ve cam xuc va hanh vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky tang xa hoi. hieu ve cam xuc va hanh vi ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky tang xa hoi. hieu ve cam xuc va hanh vi ((cua tre) or (cuu tre))*.