Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
cam thuc » am thuc, nam thuc, cam thu
so sanh » do sanh
ky lang » ky nang, ky tang, tay lang
ky dang » ky nang, ky danh
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hang » van hang, va nang, va lang
hang di » hang doi, hang vi, hang dien
te sach » toc sach
ve cam » ve cham, ve cac, va cam
di cau » da cau, diem cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (so sanh)) ((ky lang) OR (ky dang)) xa hoi. hieu ve cam thuc va hang di cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (so sanh)) ((ky lang) OR (ky dang)) xa hoi. hieu ve cam thuc va hang di cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (so sanh)) ((ky lang) OR (ky dang)) xa hoi. hieu ve cam thuc va hang di cau tren".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (so sanh)) ((ky lang) OR (ky dang)) xa hoi. hieu ve cam thuc va hang di cau tren*.