Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
va tham » van tham, va cham, va thanh
sac van » san van, sat van, tac van
cac van » cac dan
hieu va » lieu va, hieu qua
vi cau » va cau, ve cau, di cau

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) or (thuoc sach)) ty nang xa hoi. hieu va tham ((sac van) OR (cac van)) hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) ty nang xa hoi. hieu va tham ((sac van) OR (cac van)) hanh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thuoc sach)) ty nang xa hoi. hieu va tham ((sac van) OR (cac van)) hanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuoc sach)) ty nang xa hoi. hieu va tham ((sac van) OR (cac van)) hanh vi cau tren*.