Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
hieu va » hieu qua
cac tac » cac toc, cac bac, cac dac
van mat » van dat, van man, van mao
mat cua » ma cua, manh cua, mang cua
cua tre » cua te, cuu tre, cua triet
tac va » tac da, tac xa, tuc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky ((nang xa) OR (nang ma)) hoi. ((hieu va) or (lieu va)) cac tac va van mat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang ma)) hoi. ((hieu va) OR (lieu va)) cac tac va van mat cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) OR (nang ma)) hoi. ((hieu va) or (lieu va)) cac tac va van mat cua tre*".