Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
diem cau » dieu can
cam thuc » am thuc, nam thuc, cam thu
lang ha » long ha
hieu ve » hieu va, hieu van
lang xa » dang xay, lang van
thuc va » thuc vat, thuc dan, thuc day
va tinh » may tinh
sach o » sach lo, sac o, sach y
di cau » da cau
ve cam » ve cham, ve cac, va cam

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

• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach o ((lang xa) OR (lang ha)) hoi. hieu ve cam thuc va tinh ((di cau) OR (diem cau)) treo~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach o ((lang xa) or (lang ha)) hoi. hieu ve cam thuc va tinh ((di cau) OR (diem cau)) treo~".
• Adding a wildcard symbol may retrieve word variants: thu sach o ((lang xa) or (lang ha)) hoi. hieu ve cam thuc va tinh ((di cau) OR (diem cau)) treo*.