Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
hieu ly » hieu ky, lieu ly, dieu ly
nang ma » tang ma, sang ma, nang cao
hieu le » hieu ve, hieu he, tieu le
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
vi cuu » vi luu, vinh cuu
nuoc » quoc, duoc, ngoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y nang ma hoi. ((hieu le) OR (hieu ly)) dat nuoc ((va hanh) or (va danh)) vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y nang ma hoi. ((hieu le) OR (hieu ly)) dat nuoc ((va hanh) OR (va danh)) vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang ma hoi. ((hieu le) OR (hieu ly)) dat nuoc ((va hanh) or (va danh)) vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: so sach y nang ma hoi. ((hieu le) OR (hieu ly)) dat nuoc ((va hanh) or (va danh)) vi cuu tre*.