Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
thien van » thi van
hoc sach » hoc sinh, hoc cac, hoc anh
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, lieu va
hieu ve » hieu va
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
y nang » ky nang, ly nang, v nang
va cau » van cau, va cac, va dau
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach y nang x hoi. ((((hieu van) OR (hieu ve))) or (thien van)) cham thuc va hanh va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach y nang x hoi. ((((hieu van) OR (hieu ve))) OR (thien van)) cham thuc va hanh va cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach y nang x hoi. ((((hieu van) OR (hieu ve))) or (thien van)) cham thuc va hanh va cau tren*".