Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
danh dai » danh dau, danh di, danh sai
thuc day » thuc dan, thuc vat
van chat » cao chat
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
thuc va » thuc vat, thuc dan
nang xa » nang x, nang ma, 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 (lang xa)) hoi. hieu van chat ((thuc va) OR (thuc day)) danh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang xa) OR (lang xa)) hoi. hieu van chat ((thuc va) OR (thuc day)) danh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang xa) or (lang xa)) hoi. hieu van chat ((thuc va) OR (thuc day)) danh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang xa) or (lang xa)) hoi. hieu van chat ((thuc va) OR (thuc day)) danh dai cua tre*.