Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
van danh » van doanh, van anh, van hanh
dan danh » han danh, ban danh, dai danh
hoc sac » hoc sach, hoc cac, hoc mac
ca tren » cau tren, cu tren, la tren
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
sac ky » cac ky, sai ky
va cau » van cau, va cac, va dau
va ca » va cac, va cao, va cai

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sac ky ((nang xa) or (lang xa)) hoi. hieu va cau thuc ((dan danh) OR (van danh)) va ca tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sac ky ((nang xa) OR (lang xa)) hoi. hieu va cau thuc ((dan danh) OR (van danh)) va ca tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sac ky ((nang xa) or (lang xa)) hoi. hieu va cau thuc ((dan danh) OR (van danh)) va ca tren".
• Adding a wildcard symbol may retrieve word variants: hoc sac ky ((nang xa) or (lang xa)) hoi. hieu va cau thuc ((dan danh) OR (van danh)) va ca tren*.