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, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cac tac » cac toc, cac bac, cac tai
cac dac » cac dan, cac dai, cac bac
van vat » van chat, nhan vat
vat cua » mat cua, bat cua, dat cua
cua tre » cua te, cuu tre, cua triet

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 (lang xa)) hoi. hieu va ((cac tac) or (cac dac)) va van vat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (lang xa)) hoi. hieu va ((cac tac) OR (cac dac)) va van vat cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) OR (lang xa)) hoi. hieu va ((cac tac) or (cac dac)) va van vat cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) OR (lang xa)) hoi. hieu va ((cac tac) or (cac dac)) va van vat cua tre*.