Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dau tren » dau tien, dat tren, dau tieng
cau treo » cau theo, cau tren, cau triet
tang van » dang van, hoang van, trong van
van hoi » van hoa, van hoc, van hoe
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
ky tang » ky nang, ky dang, kho tang
cam duc » cam xuc, cao duc, pham duc
ve cam » ve cham, ve cac, va cam

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky tang van hoi. hieu ve cam duc va hanh vi ((cua tre) or (((dau tren) or (cau treo))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky tang van hoi. hieu ve cam duc va hanh vi ((cua tre) OR (((dau tren) OR (cau treo)))).
• Adding a wildcard symbol may retrieve word variants: toc sach ky tang van hoi. hieu ve cam duc va hanh vi ((cua tre) or (((dau tren) or (cau treo))))*.