Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
va danh » va dinh, va dan, va hanh
sach ky » sac ky, sach y, sach ty
hieu le » hieu ve, hieu he, hieu ly
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
le dat » le dan, de dat, le dac
vi cuu » vinh cuu
vi luu » vi lua
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 ky ((nang ma) OR (tang ma)) hoi. hieu le dat nuoc va danh ((vi cuu) or (vi luu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((nang ma) OR (tang ma)) hoi. hieu le dat nuoc va danh ((vi cuu) OR (vi luu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((nang ma) OR (tang ma)) hoi. hieu le dat nuoc va danh ((vi cuu) or (vi luu)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((nang ma) OR (tang ma)) hoi. hieu le dat nuoc va danh ((vi cuu) or (vi luu)) tre*.