Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
dum tren » dua tren, duc tren, dung tren
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, me hoi
va cam » va cham, va cac, va cao
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
vi dum » vi du

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach y nang ((ma hoi) OR (ma hoa)). lieu va cam ((xuc va) or (luc va)) hanh vi dum tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach y nang ((ma hoi) OR (ma hoa)). lieu va cam ((xuc va) OR (luc va)) hanh vi dum tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach y nang ((ma hoi) OR (ma hoa)). lieu va cam ((xuc va) or (luc va)) hanh vi dum tren".
• Adding a wildcard symbol may retrieve word variants: thuat sach y nang ((ma hoi) OR (ma hoa)). lieu va cam ((xuc va) or (luc va)) hanh vi dum tren*.