Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
cac thuc » cach thuc, cac thu, can thuc
dan hang » ban hang, van hang, dat hang
thuc dan » thuc hanh, hoc dan, thuc vat
toc sach » hoc sach, doc sach, thuoc sach
so sanh » do sanh
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
hang di » hang doi, hang vi, hang dien
ma hoi » mai hoi, xa hoi, ma hoa
ve cac » va cac, vien cac
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 (toc sach))) or (so sanh)) ky nang ma hoi. hieu ve cac thuc dan hang di cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((te sach) OR (toc sach))) OR (so sanh)) ky nang ma hoi. hieu ve cac thuc dan hang di cau tren.
• Adding a wildcard symbol may retrieve word variants: ((((te sach) or (toc sach))) or (so sanh)) ky nang ma hoi. hieu ve cac thuc dan hang di cau tren*.