Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dua tren » dung tren
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
cam duc » cao duc, pham duc, nam duoc
hieu ve » hieu va, hieu van
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky tang xa hoi. hieu ve ((cam duc) OR (cam xuc)) van hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky tang xa hoi. hieu ve ((cam duc) OR (cam xuc)) van hanh vi ((dua tren) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky tang xa hoi. hieu ve ((cam duc) OR (cam xuc)) van hanh vi ((dua tren) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: thu sach ky tang xa hoi. hieu ve ((cam duc) OR (cam xuc)) van hanh vi ((dua tren) or (cuu tre))*.