Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
benh da » benh dai, benh va, benh do
benh di » benh dai, ben di, benh do
cuc ban » cua ban, cac ban, cuu ban
cam cuc » cam xuc, cham cuu, pham cuc
van cam » van nam, van lam, van cau
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
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: thu sach ky ((nang xa) or (nang ma)) hoi. hieu van cam cuc ban ((benh di) OR (benh da)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang xa) OR (nang ma)) hoi. hieu van cam cuc ban ((benh di) OR (benh da)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang xa) or (nang ma)) hoi. hieu van cam cuc ban ((benh di) OR (benh da)) cua tre*".