Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dang xay » dang van, van xay
danh doi » danh di, thanh doi, dung doi
sach ky » sac ky, sach y, sach ty
van cac » van cau, van bac, dan cac
van hac » van hoc, van ha, van hai
lang xa » lang ha, lang van
truc va » thuc va, thuc vat, trung va
va danh » va dinh, va dan, va hanh
doi cua » dai cua, hoi cua
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 ((lang xa) OR (dang xay)) hoi. hieu ((van cac) or (van hac)) truc va danh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((lang xa) OR (dang xay)) hoi. hieu ((van cac) OR (van hac)) truc va danh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((lang xa) OR (dang xay)) hoi. hieu ((van cac) or (van hac)) truc va danh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((lang xa) OR (dang xay)) hoi. hieu ((van cac) or (van hac)) truc va danh doi cua tre*.