Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
lang van » dang van, tang van, hoang van
can thuc » dan thuc, van thuc, san thuc
cay thuc » cay thuoc, day thuc, cach thuc
va lang » va nang, hoa lang
van hoe » van hoa, van hoc, van hieu
so sanh » do sanh
va hanh » van hanh, va thanh, va danh
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: ((hoc sach) or (so sanh)) va lang van hoe. hieu qua ((cay thuc) or (can thuc)) va hanh vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (so sanh)) va lang van hoe. hieu qua ((cay thuc) OR (can thuc)) va hanh vi cua tu.
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (so sanh)) va lang van hoe. hieu qua ((cay thuc) or (can thuc)) va hanh vi cua tu*.