Perhaps you should try some spelling variations:
nang tri » nang tai, lang tri, nang thi
sach ky » sac ky, sach y, sach kem
sach ty » sach y, sach tu, sach thu
van bac » van ban, van hac, dan bac
van bao » van ban, van dao
va nang » van nang, da nang, cam nang
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ky) or (sach ty)) nang x hoi. thien ((van bac) OR (van bao)) nuoc va nang tri cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sach ty)) nang x hoi. thien ((van bac) OR (van bao)) nuoc va nang tri cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sach ty)) nang x hoi. thien ((van bac) OR (van bao)) nuoc va nang tri cua tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sach ty)) nang x hoi. thien ((van bac) OR (van bao)) nuoc va nang tri cua tre*.