Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » thien van, lieu va
cau thuc » cau truc, cuu thuc, can thuc
cau tren » cu tren, dau tren, ca tren
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
y nang » ky nang, ly nang, v nang
vi cau » va cau, ve cau, di cau
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: thu sach y nang x hoi. ((((hieu ve) or (hieu van))) or (hieu va)) cau thuc va hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang x hoi. ((((hieu ve) OR (hieu van))) OR (hieu va)) cau thuc va hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: thu sach y nang x hoi. ((((hieu ve) or (hieu van))) or (hieu va)) cau thuc va hanh vi cau tren*.