Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, cay thuc
can thuc » dan thuc, van thuc, cay thuc
so sach » bo sach, co sach, hoc sach
so sanh » do sanh
lang xa » lang ha, dang xay, lang van
va hanh » van hanh, va thanh, va danh
v lang » va lang, o lang, _ lang
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (so sanh)) v lang xa hoi. hieu qua ((cac thuc) OR (can thuc)) va hanh vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) v lang xa hoi. hieu qua ((cac thuc) OR (can thuc)) va hanh vi cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) or (so sanh)) v lang xa hoi. hieu qua ((cac thuc) OR (can thuc)) va hanh vi cua tu".
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (so sanh)) v lang xa hoi. hieu qua ((cac thuc) OR (can thuc)) va hanh vi cua tu*.