Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu van
hieu va » lieu va, hieu qua
cuu tac » cuu dac, cuu cac, cuu xac
va tich » va tinh, va dich
y nang » ky nang, ly nang, v nang
tac va » tac da, tac xa, tuc va
va cua » va chua, via cua, ma cua
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach y nang xa hoi. ((hieu ve) or (hieu va)) cuu tac va tich ((va cua) OR (ca cua)) tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach y nang xa hoi. ((hieu ve) OR (hieu va)) cuu tac va tich ((va cua) OR (ca cua)) tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach y nang xa hoi. ((hieu ve) or (hieu va)) cuu tac va tich ((va cua) OR (ca cua)) tu".
• Adding a wildcard symbol may retrieve word variants: thuoc sach y nang xa hoi. ((hieu ve) or (hieu va)) cuu tac va tich ((va cua) OR (ca cua)) tu*.