Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
doan thi » dan thi, doanh tai, hoang thi
lang van » dang van, hoang van, giang van
tang van » dang van, hoang van, trong van
cam thuc » am thuc, nam thuc, cam thu
tu cach » tu cac
thi cua » thai cua, thi cuc, tri cua
va doan » va doanh, van doan, va dan
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (thu sach)) ky ((lang van) or (tang van)) hoi. hieu ve cam thuc va doan thi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (thu sach)) ky ((lang van) OR (tang van)) hoi. hieu ve cam thuc va doan thi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (thu sach)) ky ((lang van) or (tang van)) hoi. hieu ve cam thuc va doan thi cua tre*.