Perhaps you should try some spelling variations:
thanh vien » nhan vien, thanh van
thanh ve » hanh ve, thanh va, thanh van
sach ky » sach y, sach ty, sach kem
cac tuc » cac toc, cac tu, cac tac
qua cac » cua cac
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, truc va, tuc xa
sac ky » cac ky, sai ky

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