Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, nang ma
hieu vu » hieu va, hieu ve, dieu vu
hieu su » hieu sau, tieu su, hieu so
cham so » cham soc, cham o, ham so
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
di cau » da cau, diem cau
so va » so van, so vat, su va

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 v nang xa hoi. ((hieu vu) or (hieu su)) cham so va danh di cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v nang xa hoi. ((hieu vu) OR (hieu su)) cham so va danh di cau tren.
• Adding a wildcard symbol may retrieve word variants: toc sach v nang xa hoi. ((hieu vu) or (hieu su)) cham so va danh di cau tren*.