Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
danh vai » danh sai, danh va, doanh van
hieu van » thien van, lieu va, hieu ve
dat tren » dat trong, dua tren
thi hong » thi cong, thi phuong, thi hanh
thi hang » thi hanh, thi nang, thi thanh
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
va danh » va dinh, va dan, va hanh
vai dat » cai dat, va dat, van dat

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((thi hang) OR (thi hong)) xa hoi. ((hieu va) OR (hieu van)) cam duc va danh vai dat tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((thi hang) OR (thi hong)) xa hoi. ((hieu va) or (hieu van)) cam duc va danh vai dat tren~".
• Adding a wildcard symbol may retrieve word variants: toc sach ((thi hang) OR (thi hong)) xa hoi. ((hieu va) or (hieu van)) cam duc va danh vai dat tren*.