Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach va » sach xa, sach ha, sach dao
va dinh » van dinh, va kinh, va tinh
va danh » va dan, va hanh, dia danh
cham so » cham soc, cham o, ham so
hieu su » hieu sau, tieu su, hieu so
hieu vu » hieu va, hieu ve, dieu vu
nang xa » nang x, lang xa, nang ma
va nang » van nang, da nang, cam nang
cuu tre » cua tre, cau tren, cau treo
di cuu » di cau, di cua, dinh cuu

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 va nang xa hoi. ((hieu vu) or (hieu su)) cham so ((va danh) OR (va dinh)) di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach va nang xa hoi. ((hieu vu) OR (hieu su)) cham so ((va danh) OR (va dinh)) di cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach va nang xa hoi. ((hieu vu) or (hieu su)) cham so ((va danh) OR (va dinh)) di cuu tre".
• Adding a wildcard symbol may retrieve word variants: toc sach va nang xa hoi. ((hieu vu) or (hieu su)) cham so ((va danh) OR (va dinh)) di cuu tre*.