Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van dinh » van minh, van dich, xuan dinh
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, nang ma
va dinh » va kinh, va tinh, vu dinh
duc cau » duc hau, duc mau, duc cac
y nang » ky nang, ly nang, v nang
va cam » va cham, va cao, va cai

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 y nang xa hoi. lieu ((va cam) or (va cac)) luc ((va dinh) OR (van dinh)) duc cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang xa hoi. lieu ((va cam) OR (va cac)) luc ((va dinh) OR (van dinh)) duc cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang xa hoi. lieu ((va cam) or (va cac)) luc ((va dinh) OR (van dinh)) duc cau tren".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang xa hoi. lieu ((va cam) or (va cac)) luc ((va dinh) OR (van dinh)) duc cau tren*.