Perhaps you should try some spelling variations:
cay mang » cach mang, cay cong, day manh
dat tren » dat trong, dua tren
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
xuc van » duc van, luc van, xuc ban
vuc van » duc van, luc van, thuc van
va cau » van cau, va cac, va dau
vi dat » voi dat, vi dai, va dat

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((cay mang) OR (cay mac)) xa hoi. hieu va cau ((xuc van) or (vuc van)) hanh vi dat tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((cay mang) OR (cay mac)) xa hoi. hieu va cau ((xuc van) OR (vuc van)) hanh vi dat tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((cay mang) OR (cay mac)) xa hoi. hieu va cau ((xuc van) or (vuc van)) hanh vi dat tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ((cay mang) OR (cay mac)) xa hoi. hieu va cau ((xuc van) or (vuc van)) hanh vi dat tren*.