Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
dinh vai » dinh van, dinh vi, dinh va
hieu va » lieu va, hieu qua
cu tren » tu tren, dua tren
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
vai cu » vai cua, van cu
va cam » va cham, va cac, va cao
so va » so van, so vat, su va
o va » do va, co va, bo va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) OR (thuoc sach)) ky lang xa hoi. hieu va cam ((o va) or (so va)) dinh vai cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) ky lang xa hoi. hieu va cam ((o va) OR (so va)) dinh vai cu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (thuoc sach)) ky lang xa hoi. hieu va cam ((o va) or (so va)) dinh vai cu tren".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (thuoc sach)) ky lang xa hoi. hieu va cam ((o va) or (so va)) dinh vai cu tren*.