Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
benh da » benh dai, benh va, benh do
benh di » benh dai, ben di, benh do
cao duc » dao duc, cao suc, giao duc
cau duc » cau luc, chu duc, cau truc
nang xa » nang x, lang xa, nang ma
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 hoi. hieu van ((cau duc) OR (cao duc)) 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 hoi. hieu van ((cau duc) OR (cao duc)) 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 hoi. hieu van ((cau duc) OR (cao duc)) ban ((benh di) or (benh da)) cua tre*".