Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
hieu su » hieu sau, tieu su, hieu so
danh di » danh du, xanh di, danh dien
va danh » va dinh, va dan, va hanh
cham so » cham soc, cham o, ham so
cuu tre » cua tre, cau tren, cau treo
hieu vu » hieu va, hieu ve, dieu vu
nang xa » nang x, lang xa, nang ma
v nang » va nang, vu nang, van nang
di cuu » di cau, di cua, dinh cuu
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) OR (thuoc sach)) v nang xa hoi. ((hieu vu) or (hieu su)) cham so va danh di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) v nang xa hoi. ((hieu vu) OR (hieu su)) cham so va danh di cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (thuoc sach)) v nang xa hoi. ((hieu vu) or (hieu su)) cham so va danh di cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (thuoc sach)) v nang xa hoi. ((hieu vu) or (hieu su)) cham so va danh di cuu tre*.